The city of Nice seen from the surrounding hillside bathed in sunshine

Home Bike Reviews

KLX 250 The Little Bike That Could

Review Date 12 Mar 2019

By Bob Northern

The KLX pulls off a neat trick of looking like a full size bike (it is very tall) whilst weighing less than many 125cc machines. Some reviews will say the KLX is heavy at 131KG, but those reviews are comparing the KLX to hard-core offroad bikes. The KLX is a trail bike and in that company it is very lightweight, significantly lighter than the CRF250L which has now sprouted ABS to add a few extra KG.

Bob's KLX250 motorcycle set in a beach with steep rocky cliffs

The engine is well oversquare and the power characteristic is that of a tuned two stroke, it needs to rev, indeed given it’s small displacement it is surprisingly harsh at low RPM. In normal riding 5000 RPM is the lowest that can be used. Peak torque is at 7100 RPM and this combined with peak power at 7500RPM means the engine “comes on cam” in a pleasing way from 6500 RPM and pulls strongly through to 9500 RPM, when the power starts to tail off again.

It is essential to alter the inlet cam timing. For some reason Kawasaki have left the valve overlap the same as for the KLX300R, which is a screaming competition engine. On the KLX250 this means that the overlap is designed for an RPM which the engine never achieves due to the lower redline.

It is easy to add 10 degrees of inlet cam retard by removing the inlet cam sprocket, walking it round two teeth and re-attaching the sprocket using the other set of holes. In fact it’s suspiciously easy, one can almost imagine Kawasaki did it on purpose – maybe the bike won’t pass noise or emissions tests in its tuned up state, but the engineers left an easy back door for knowledgeable owners to unleash the full potential of the bike. The difference is like night and day, in standard trim the bike gains speed, in tuned form it actually pulls.

There is a further restriction in that the engine is limited to 6500 RPM in the top three gears. This is easily overcome by joining two wires together and then the engine will rev out in every gear.

On road performance in de-restricted form is punchy and enjoyable, within the restrictions of the speed limit there is a lot of fun to be had. In 5th gear peak torque is at 60 MPH so the bike loves hooning around twisty A and B roads. Out on the motorway the bike is less at home but it is certainly not lost. It’s quite happy to run along at 65 to 70 MPH with enough left to pull around middle lane hogs.

If I ever find myself frustrated that the bike won’t pull I just have to remind myself about the 7500 RPM peak power and change down a gear – it really needs to be revved to make power.

The six speed gearbox has a very wide set of ratios, there is more than a 3:1 difference between 1st and 6th gear. 1st gear is low enough for all standard green lane activities (some clutch slip required when it gets more technical) and 6th is an overdrive gear. In 6th gear 1000 RPM is 10 MPH. There is not enough torque to rev out in 6th gear, the bike will achieve a higher top speed in 5th than in 6th. On A and B roads 5th is the best gear, which covers 40 MPH to 70 MPH, peak torque coming in at 60 MPH, for the steepest climbs into the strongest headwinds 4th  gear is sometimes needed and in 4th peak torque is at 53 MPH.

Fuel economy is usually around 80 MPG depending on riding style. The fuel tank is tiny, holding only 7 litres, with a warning light that activates when there is 2.3l of fuel left. Given the economy available this typically means the fuel light comes on around 95 miles and then there is 35 to 40 miles of range left. I feel comfortable riding 110 miles between fill ups and I think that is fine given the type of bike the KLX is. 

The fuelling is perfect, no snatchiness no holes in the torque curve, Kawasaki really seem to have EFI sorted, the Keihin system used on the KLX250 is wonderful.

Handling is dominated by the supreme lack of mass, on knobbly or semi-knobbly tyres the KLX can get quite twitchy above 65 MPH, especially in a cross-wind. I have fitted a small windscreen which adds to the instability by acting as a sail which twists the bars in the wind. Cornering and braking are both immediate and quick, again due to the lack of mass. 

It is possible to ride the KLX in a very sloppy manner, it’s not really necessary to set up for a corner since speed can be scrubbed off mid bend without causing instability. Riding in the wet or the dry is largely the same, sharp corners in the wet hold no fear because the bike is so light there is virtually no danger of sliding out. 

The only worry about long term KLX ownership is that the next time I ride a “normal” bike I’ll end up in a ditch because I will be expecting it handle like the KLX handles. 

Off road performance is superb, 10” of suspension travel, fully adjustable shock and forks and light weight make green-lane riding a real pleasure. Keep the revs up and it will easily spin the back tyre to help with steep climbs on loose surfaces. 

Bob's KLX250 in a disused quarry

Having ridden a CRF250L on three occasions I suspect that the first-time rider would feel that the CRF was faster of the two, an illusion caused by the CRF having more torque available lower down the rev range. Get used to the KLX however, give it the thrashing it wants and the KLX will leave the CRF behind on road and off.

Comfort is a mixed bag. The bike is very tall with a good distance between the pegs and seat, which suits my long legs, but the seat is very narrow indeed. It’s in keeping with the dirt bike part of the KLX DNA but it does limit comfort to just an hour in the saddle before I find myself concentrating on my backside rather than the road ahead. 

I fitted a Sargent comfort seat, which has a wider seat base than standard. The seat is narrow at the front for off road riding but has a much wider rear section, on a long ride I slide back onto the wide section and it is bliss. 

The pillion pegs are mounted direct to the frame and they are quite high, pillions will need to be relatively small in stature, doubly so because the seat is not overly long. My 10 year daughter is quite happy back there but I suspect an adult would not be.

Luggage capability is poor as standard but a variety of racks are available, I fitted a cheap “Alpha Rider” item which adds very little bulk to the rear end yet provides a very secure and stable base to strap down my 35 litre airport bag. The rack also provides several much needed hand-hold points for manhandling the machine around.

Instrumentation is comprehensive for a trail bike. An LCD instrument gives RPM, speed, a clock, odometer and two trip-meters. Warning lights include fuel, temperature, neutral, high beam, indicators and EFI. Strangely there is no oil warning light, but the level is easy to check as there is a sight glass in the clutch cover. No oil should be used between changes.

Servicing is easy, the oil capacity is only 1.3 litres which I use as encouragement to change the oil every 1000 miles. The manual states 6000 miles but that seems like a very long time to leave oil in a hardworking engine. 

All the cycle parts and suspension are pretty standard stuff, changing the fork oil in USD forks is always more involved than for conventional forks but well within the remit of the home mechanic. Valve clearances are shim and bucket which brings the benefits of long service intervals but also the extra work required when the clearances do need to be changed. 

The air filter is washable and the fuel tank is no more difficult to remove than on a pre EFI machine, just one electrical connector, one fuel hose connector and two breather pipes.

Healtech make an interface which plugs into the diagnostic port under the saddle. Connected to a USB port on a laptop this enables full EFI diagnostics to be performed. It’s possible to read all sensor input values, run the fuel pump, activate the 2nd air solenoid, active the cooling fan and more. When I buy an EFI bike I always run a diagnostic to check for issues and in the case of one of my KLXs the Healtech revealed that the cooling fan was non-functioning. It had seized and blown the fuse. I assume a previous owner had made merry with the jet-wash and water had got into the bearings. A second-hand fan from an internet auction site cured the issue.

For those who don’t want to invest in an interface there is a basic diagnostic function built into the bike, by connecting a wire to ground the ECU will flash the EFI warning light to indicate fault codes.

The KLX250 was discontinued in the UK when Euro 4 came into force, but launched as a new model in USA in 2018 so parts supply is as good as for any current model. My KLX250 in its tuned state is enough bike for everything. It quite happily cruises for hundreds of miles on the motorways, carves through traffic, careens down green lanes. It’s light enough to ride in the snow and ice, it’s stone reliable, good on fuel, cheap to tax and insure, extremely easy to work on and massively involving and fun to ride.

We'd like to publish your motorcycle reviews, rides, guides or just entertaining tales here on Bikes And Travels. Contact

Reader's Comments

Keith m said :-
Nice review. I've always liked these but was always put off with the fact it only had a few more hp than a 125. Can't understand why it was potentially restricted as I think it's the same engine as in the z250sl which puts out about 25hp.
17/03/2019 10:05:13 UTC
Ren - The Ed said :-
The Z250SL is something around 27bhp. I have zero idea what the cam timing is though but I know Sharon's Z250SL goes very well considering it's humble capacity. I also consider it to be pretty grunty with power everywhere you need it. Journalist reviews say it's revvy but I've not found that at all.
18/03/2019 09:40:28 UTC
Bob said :-
I'd like to dyno the KLX now it's tuned - I suspect it's closer to the Z250SL now.
I mentioned the tendency to instability in the review, I don't want to overplay it as many lightweight trail bikes get a bit squirrely at high speed, but I wonder if that is why the bike is so restricted as standard.

In standard trim 65MPH is your lot because it won't rev above 6500RPM in 4th, 5th or 6th. I ran the KLX standard for a couple of months and it was OK but I was always having to make excuses for it and selecting routes which didn't include steep hills and overtaking wasn't an option. Now I can blast around anywhere and whip past dawdling cars on the A roads.
18/03/2019 07:45:03 UTC
Keith m said :-
What ever the reason it was clearly a conscious decision by Kawasaki to restrict this bike if it won't rev out in the top three gears. But it sounds like now after the mods it's the bike it should have been from the crate.
18/03/2019 10:34:17 UTC
Bob said :-
One thing I forgot to mention is that I've changed from O ring to non-O ring chain.
The difference in smoothness and performance is wonderful.
I have a Scottoiler which I usually have set to "Exxon Valdez" level, from the adjustments I've had to make I estimate the non-O ring chain will last probably 1/2 as long as the O ring version but since the non-O ring chain was 1/3 the price it works out better.
I had constant chain problems with the KLX when it was running O ring chain, lots of noise and graunching, all cured now.
26/03/2019 09:03:23 UTC
Wendy's Peters said :-
Where can o get my 2009 KLX250 de restricted.
I live near Portsmouth UK.
27/03/2019 07:22:08 UTC
Bob said :-
It's easy to do.
Link out the clutch switch and change the cam timing.
If you're not confident to do it yourself go to a non-main dealer motorcycle shop and get them to do it. I'd guess at a maximum of 2 hours labour for the work and no parts will be required. Use the attached image, if your chosen mechanic doesn't understand it then don't let them work on your bike.
Look up "Marcelino Cam Mod" - there is a lot of information out there.
Don't alter the exhaust timing. I've tried mine with the just the inlet altered and then with both inlet and exhaust altered and it's much better with just the inlet altered.
It will completely transform the bike.

28/03/2019 10:42:50 UTC
Glenn said :-
I'm questioning my CRF250l purchase now.
Nice in depth review.
28/03/2019 10:42:58 UTC
Bob said :-
To clarify, you drop the inlet sprocket off the cam and walk the chain 2 teeth around the sprocket so that the "IN" timing mark on the left disappears below the head and then pop the sprocket back on the cam.

You will then see that the threaded hole in the cam is now very nearly aligned with the "EX" marked hole in the sprocket (it was aligned with the "IN" marked hole before).

You then rotate the cam a tiny bit to properly align the threaded hole in the cam with the "EX" marked hole in the sprocket - this is where the 10 degree inlet retard comes from.

Finally, tighten the sprocket and torque down the bolts.

That is it. You will need to link out the clutch switch otherwise you won't be able enjoy the effects of the mod because the engine will not rev beyond 6500RPM.
28/03/2019 10:52:46 UTC
Bob said :-
Glenn, the CRF is a fine machine - I very nearly bought one (very nearly bought two actually), it was a test ride on a CRF250L which opened my eyes to the idea of running a 250 as my only bike, I'd always had 600 and 650 singles previously.
In the end I bought a KLX because it was cheap and I didn't know if my 250 experiment would work so I wanted to limit my investment.
I have to say that for normal road and green lane use "out of the box" the CRF is the better machine, it's certainly more comfortable and doesn't require any mods (as far as I'm aware) to make it every day useable.
But, mod a KLX and for me it overtakes the CRF, it's lighter with better (fully adjustable) suspension and the little engine turns into a proper Kawasaki screamer. I find the maintainence is easy, the bike is a real pleasure to work on too.
I've got five KLX250s now, one has only 800 miles on it and looks like it just rolled out of the factory, that sits in the corner under a sheet with superplus in the tank and battery tender.
The one I ride daily has just passed 19000 miles, 6000 of those in my ownership (since October) and it starts and rides like new.
28/03/2019 11:09:49 UTC
Henrik said :-
Interesting review Bob

I wonder, how comes you ended up with five KLX250's ? :-)
28/03/2019 01:21:10 UTC
Ian Soady said :-
Bob always likes to have several of the same model. It used to be Honda SLRs......
28/03/2019 01:53:34 UTC
Bob said :-
How? I like 'em that's how!
I admit I may take having spares further than most but I am convinced that having more than one of the same bike is a good policy. My daily rider recently popped a fork seal, I had the choice of fitting a spare fork or riding one of the others whilst I waited for the seal and the seal driver to arrive.
Several times is't paid off for me. I ride all year round, several times a week and I can't be without a bike.

I have in the past persued the idea of having a big cheap bike to cover the miles and save my favourite bike for Sunday best, but my favourite bike is my favourite because I like riding it. What would be the point of riding a bike I don't like to somewhere I want to be and then not being able to ride my favourite bike when I get there?

In my fevered brain this all makes perfect sense - I have so many KLXs because I ride a lot of miles and it's a small engine, which with the best will in the world isn't going to last as long as a 750 (although Ren's exploits with the 125 might speak otherwise) and they're not available new in the EU any more so I wanted to ensure my continued enjoyment of the machine. I'm still in love with it, I browse Ebay and Autotrader and visit the bike dealers and I haven't seen anything else I'd rather own.

I think I've got enough now, there are two more low mileage engines on the shelf plus fuel pumps, ECUs, throttl bodies, brake calipers, shocks, forks, instrument clusters etc...
28/03/2019 02:23:20 UTC
Bob said :-
Yesterday I took a test ride on a Versys X300.
It was interesting, the Versys didn't pull as hard as my modified KLX. It's top speed was higher because it pulls for longer through the rev range but it's incredibly low geared spinning at 7000 RPM for just 60 MPH.
There's a long 1:4 hill near here that I use for testing bikes, going up there the Versys wasn't able to hold more that 60MPH which is exactly the same speed my KLX will hold. The difference is the KLX will do it at 8000 RPM in 4th, the versys was over 10000 RPM in the same gear.
So given that the standard torque figure for the KLX and Versys are roughly the same, this is confirmation for me that the modified cam timing definitely increases torque on the KLX, it has a good strong midrange that's lacking as standard.
The Versys in comparison felt quite weak, it was a pleasure to get back on the KLX for the ride home.
06/04/2019 04:30:30 UTC
Keith m said :-
The Versys shares the same engine as my z300 be they are a rev hungry little number and 70 comes up at around 8000rpm. I wouldn't call it was lacking in torque but I have spent a lot of time on two strokes. What would be interesting would be a Dyno graph between your klx250 and the z250sl like Sharon's which doesn't appear to have any of the restrictions that the klx has or had.
07/04/2019 10:22:30 UTC
Ren - The Ed said :-
I've reviewed the Z300 on here and I agree, it's a revvy motor. I don't know if Kwakker changed the engine or mapping etc to alter the character of the motor on the Versys 300, but having seen reviews and your thoughts Bob it seems not. When Kawasaki released the Versys I was surprised they used the 300 twin rather than the 250 single, that would have been my choice.

I wonder if it was more to do with emissions? The KLX motor is "long legged" now but then Honda seems to manage with the 250/300 single in the CRF/CBR. There are many mysteries that are not revealed to the humble buyers like us (the truth is out there...)

In spite of our opinions it's also worth noting not everyone thinks like us! Keith m - are you loving your Z300?
08/04/2019 07:36:39 UTC
Bob said :-
The main thing for me was the ridiculous impossibly low gearing! 1st gear was all but useless.
I'd be looking to drop a couple of teeth (at least) from the rear sprocket, assuming the electronics would allow it.
The engine was very smooth and did make power across a very wide rev range, but I couldn't use it because I had to hook another gear. I was in 6th gear at 40MPH. This spoils the bike for me.

Another thing and this is just down to my attitudes, but the KLX and the X300 have small engines.
Sooner or later your small engine will run out of shove when faced with a steep hill and/or headwind. When the KLX runs out of puff I don't mind because it is such a small and lightweight trail bike, I tuck down against the wind and grind up the hill.
Now, the X300 doesn't look or feel like a small bike, it doesn't weigh like a small bike either and with it's large fairing and windscreen it seems to me it's attitude is "writing cheques the engine can't cash" so when it runs out of power it feels much worse.

On paper the X300 has 19 odd HP over the KLX so I don't doubt that it'll cover ground more quickly, but I can't ride along at 8000RPM everywhere.
08/04/2019 09:25:55 UTC
Henrik said :-
Spares and multiple bikes:

Thanks Rob, I am a bit in the same boat, just with Hyosung XRX, got 3, one without plates just for ripping, first I got one as the only real cheap option available around here for being placed permanent in my weekend-house far out in the Swedish woods. I wanted nothing expensive, nothing to worry about being stolen, and nothing being to expensive to ensure

It then went downhill with Hyosung, spares drying quickly out, I could go two ways, get rid of it, or supply with spares

Next step was I realised the problems with the bike, quickly developing rust, especially terrible on the front legs, and electrical problems an-mass, stators puffing of, conectors and stear-contats being dead afte 24 mouths, etc etc

Long story, I am not sure I would do the same again, but I have passed the point of no return

250 vs 300 ccm:

Also a mystory to me, in general we see most 250ccm around 25 hp, and most 300ccm around 40hp

So these 300ccm's tend to be pushed so much more, (hp/ccm), much OVER the line I would say, I will question longevity

RPM on my Inazuma is more than enough as it is

KLX vs CRF250L:

KLX might have an edge, but is not realy an option in DK as there is simply not enough on the second-hand market, but I consider the CRF250L as it has become some new kind of "classic" already, hundreds of them are seen touring the world, with great success, the production still holds up, also in this part of the world, spares and support will be VERY long, no need to secure with extra bikes and parts for many years to come, in no way pefect, but just a damm good and universal bike still,..

To me it might end up with DL250 though, the Inazuma is fine for me it seems, same engine, but better seathight, better position, and larger tank, (18L vs 13L), nicer look, what is my greates wishes compared to the Inazuma

Both Inazuma and DL250 got a very comfortable seat, good luggage options, and might be better fit for very long road trips in Norway and Sweden, very remote locations, on the buttomline, compared to both KLX and CRF,..

Like said, in my case it would be CRF250L for a more agile off-road type, first problem would be to add permantly connected auxiliary extra rear-tank, I don't lots lots of small extra cans, it must be possible to drive around 500 km without refuelling, next thing would be seat-comfort, (driving over 10 hours, 8-900 km some days), then comes luggage-options for longer trips,... it all sums up,...

What I consider right now is to get rid of the KLE500-project also, its been two years delayed already, and then maybe only have one single DL250 for longer road trips, and a maybe, just maybe, an older CRF250L for smaller trips 2-3 days plus joy-rides in the local forest, (when the Hyosungs are worn out that is),..

Realy need to keep it more simple, and cheaper, focusing on getting the trips actually done, and optimise the long term economy becousre I might retire in 5-6 years, with a little luck :-) (but on a low budget)

Sofar just enjoy the Zuma, for some long distance road-trips :-)

08/04/2019 10:19:59 UTC
Ren - The Ed said :-
Size is a funny thing. The problem as pointed out is the KLX and CRF are both light bikes but the price is skinny seats. The Versys 300 and Strom 250 are (relatively speaking) huge, fat and heavy. The advantage is there's a proper seat (although the Versys' seat is very hard) and there's spaces and places for luggage.

In a perfect world a motorcycle would be as big as a GS1200 for luggage, high speed stability, and comfort. As small as a KLX125 for ease of use, economy, and off road ability. It would have a smooth V8 engine that has the torque and simplicity of a single. Everything is a compromise. Manufacturers make a selection of bike, each on compromised in some way. It's up to us to decide what compromises we make - hence the bike we choose.

Now - if we could get our heads together and create this perfect motorcycle we'll all be millionaires. Then we can all retire and ride around on our perfect bikes!
08/04/2019 10:52:35 UTC
Bob said :-
The KLX250 standard saddle is horrendous - absolute torture.
The CRF250 saddle is typical Honda - very comfortable.
I have fixed the KLX with a Sargent saddle but it cost me £340 do it.
As I said in the review I think the CRF is the more complete bike out of the crate, if you want to just buy and use a bike without messing then the CRF is better.
For me it's all about weight, if that Versys was 145KG I wouldn't be complaining. As it stands it feels like my old KLE500 but with half the power and hence a bit lackluster.
I did have a test ride on a CBR250R and that was much better, mainly because it was lighter but you're still left with the proposition of struggling up a steep hill but this time on a "sports" bike, which seems even worse.
I guess what I mean is that I can forgive the KLX it's shortcomings because nobody expects a trail bike to be fast on the motorways, whereas the Versys et al kind of look like they ought to be but aren't.

My seat of the pants dyno says the KLX is now over 20ftlbs and probably 23-24Hp, compared to 17ftlbs and 21HP. It feels even better because that torque is available from 6K to 9K RPM which in 5th gear gets you from 50MPH to 80MPH - perfect for "normal" roads and if I want I can potter around and never need to go over 7K.
08/04/2019 11:55:13 UTC
Bob said :-
Oh yes, I forgot - Henrik, you mention fuel range. That is a big issue for the KLX.
I seem to be constantly filling the tank. The fuel economy is very good, 75MPG is the lowest I've seen but the tank is tiny. I have been putting thought into how I could increase the fuel range but so far I'm stuck with the strap a jerry can on the back option.....
08/04/2019 11:58:15 UTC
Keith m said :-
Ren. Yes still loving the z300. The only thing I would change would be the seat which seems devoid of foam.
08/04/2019 10:33:04 UTC
Bob said :-
It's a Kawasaki thing.
The standard KLX seat is unusable.
The KLE500 I used to have had a hard seat on slope so it was like some kind of coccyx battering instrument.
The Versys X300 I rode the other day had a plank (or at least it felt like it) where the seat should be.
The Sargent seat I fitted to the KLX was the best £340 I've ever spent.
09/04/2019 08:27:26 UTC
Ren - The Ed said :-
Yeah the seat on Sharon's Z250SL ain't exactly "plush". Sharon's OK because she's not heavy enough to trouble even the thin padding.
09/04/2019 12:04:55 UTC
Upt'North said :-
Henrik, I don't think you're trying hard enough with the luggage, there must be a cm3 somewhere for another bag......
09/04/2019 02:07:13 UTC
Henrik said :-
Upt'North, ass everyone knows very well. English is not my spoken language, but still, I am not more left behind than I can see the joke :-)

In my own defense, that picture was from my 6 days travel, very remote location, so many tools, tubes, air-patrons, 2 x 2.5L extra fuel, (one givi can in each side-bag), tent, sleeping bag, inflateable madress, food/cooking for most the trip, and last, but not the least, all my camera-equipment, unfortunately my foto-session on Lofoten was spoiled by rain
09/04/2019 06:59:39 UTC
Henrik said :-
Bob, I agree about Kawasaki and seats, the seat on KLE500 rides me like a nightmare, and its one out of several reasons that I might scrap this project to garbadge container. The seat is angled downwords to the thank, so as you ride along you constantly glide down to the tank, until your balls get flat, then you push your self back, and once again, and....

Some company in Grease remake the seats on the old frame, but they end up looking like something from a Goldwing, or a horse-saddle,... so not even if I did waste further into the project there is a solution,... and also no oversize tank

BTW I vaguely seems to remember there is a oversize tank available to KLX250 from acerbic or IMS,..

09/04/2019 07:25:33 UTC
Upt'North said :-
Regarding the fuel tank issue, isn't it the case that they're never big enough. I think I've got about 6 gallons available to me but at brisk Autoroute pace I'm still looking for fuel at about 200 miles and sweating at 240. I think it probably gets easier with age, who can ride that long without wanting a coffee and a pee. Not me. Also if you have a tank in the normal position it can get very top heavy, luckily mine is under my arris. I know riders of ST13's which have a two part tank regularly remark on the top heavy feel at low speed.
10/04/2019 09:43:22 UTC
Ren - The Ed said :-
Ya'll need a CBF125. It holds around 13 litres which is good for a 125. It also returns good economy hence it has a 300 mile tank range - easily. I have managed 350 miles before I too was "sweating".
10/04/2019 08:33:23 UTC
Upt'North said :-
Ed, whether or not yours is big enough is really not for you to decide.
Anyway, can't stop, I've got potatoes to plant........and a Pan in the garage that requires a bit of graft. Still waiting for a new bottom hose from Silvers.
350 miles......pfffft.
11/04/2019 09:14:11 UTC
Henrik said :-
300 miles is OK ,.... just about OK

Guess its the around the same with DL250 and its 18L tank

Right I go 500+ miles some days on the Zuma ,.. with only 13L ,.. and the need NOT to miss a gasstation in remote locations, (just to be safe), I find my self refuelling 5-6 times each day ,... sometimes planning my route due to the need to fuel frequently ,.. not OK

And then comes new plans to go at even more far out in the wilderness

Sometimes you comes to gasstation and its closed or out of function, there must be a margin for that also

11/04/2019 09:56:23 UTC
Bob said :-
A bit more on this.
I've just test ridden a CRF250L with Takagawa 305cc big bore, high lift camshafts, fuel controller, powerbomb header and (loud) FMF tail pipe. According to Takagawa in this trim the CRF should be pushing nearly 30HP.
I rode down to the dealers and back again on my inlet cam re-timed KLX so it was a good chance for a back to back comparison.
If the Takagawa CRF makes 30HP and the stock KLX is 21HP, then my modded one feels to me more like 25 or 26HP. The CRF had a bigger spread of torque, but when the KLX comes on cam it's not far behind.
Given that the former keeper of the CRF sunk about £1000 into the bike, I'm happy to stick with my KLX.
27/04/2019 04:52:47 UTC
Bob said :-
Interesting things I've learned about fuel injection on the KLX.
A popular mod is to fit an O2 eliminator, they are cheap enough so I thought "why not".
I removed the the O2 sensor, fitted the supplied bung and connected the eliminator to the plug in the wiring loom.
I was surprised to find that there was a not insignificant improvement in low and mid-range torque, the bike felt smoother and happier. I ran it round like this for a few days, there were no problems, I did notice that I was getting 5 to 10 miles less from a tank (but that could have been down to the way I was riding the bike) and that the fan was coming on sometimes.

I decided to investigate, I refitted the O2 sensor and connected a DVM set to 0-2V and taped this to the fuel tank. At this point the O2 sensor was only connected to the DVM, not to the bike. I found that on low throttle openings the voltage was 0.45 to 0.55V, indicating the perfect stoichiometric ratio and that on WOT (Wide Open Throttle) the voltage went to 0.8V indicating a richer mixture. This all looked very good and is in line with accepted practice.

Next I reconnected the O2 sensor to the bike (with the DVM still connected) and I was surprised to see that the voltage was 0.8 to 0.95V most of the time, indicating a rich mixture most of the time. At tick-over I saw the oscillating 0.1 to 0.8V signal that I'm used to seeing on my car, everywhere else it was 0.8V or above.

Hmmm, why is it like this? I connected my Healtech to the ECU and went for a datalogging ride. When veiwing the data with the O2 connected and with the O2 eliminator connected one measurement leapt out - the coolant temperature. I have a test run near my house, a dual carriageway of 5 miles which includes a 2 mile climb. During that run with the O2 sensor connected the coolant temperature peaked at 95C, with the O2 eliminator the coolant temperature peaked at 111C.

So I think Kawasaki set the bike up to run a rich 12.5:1 to keep it cool. These bikes are well known as cool runners and now I think this explains why I noticed the cooling fan coming on (I've never had it come on before in 9000 miles of road and trails).

Therefore I've decided to re-instate the O2 sensor and accept the standard performance.

What's really interesting is that on the forums everybody says that the O2 eliminator improves performance by enrichening the mixture when in fact it's the exact opposite. So all those people who fit a loud exhaust, remove the airbox lid and then fit an O2 elimininator assuming this device counteracts the leaning effects are in fact running their KLX250s horribly lean and horribly hot!

Live and learn.......

12/07/2019 09:58:06 UTC
Ian Soady said :-
That is surprising as you say Bob as generally the manufacturers seem to set the A/F lean particularly around the 3000 rpm point.

Some years ago I had a Triumph Tiger 955i and these were notorious for bogging down in the 2-3,000 rpm area. I had a Tuneboy setup which allowed me to look at the a/f maps and not surprisingly there was a real weak point in that area. The Triumph ECU used that setting to control when it ran in closed loop mode - ie used the O2 sensor output to adjust the fuelling. According to the best information I had, it only ran in closed loop when the target was 14.5, which it was in that rev range especially with smallish throttle openings. Closed loop running tended to make the system hunt as it would alternately over- and under- fuel.

Using Tuneboy to adjust the A/F ratio to 13.0 across that range meant that it was no longer trying to run in closed loop and would just accept what was in the map and effectively ignore the O2 reading. It improved rideability no end.

I must say this was all several years ago so I may have some of the details a bit wrong.....

This picture is the standard map:

12/07/2019 10:47:43 UTC
Ian Soady said :-
Where's my pic?

This should be the modified one:

12/07/2019 10:48:43 UTC
Ian Soady said :-
Didn't give the standard one time to upload: here it is.

12/07/2019 10:49:28 UTC
Ian Soady said :-
I did say it was a long time ago - this is actually the real improved one.

12/07/2019 10:51:02 UTC
Bob said :-
I did see the A/F ratio lean at low RPM, presumably for emission tests, it's everywhere else it was rich.

I thought about an EJK / Powercommander, but there'd be nothing to gain unless I changed the exhaust or intake arrangements and now I don't believe the cooling system would keep up anyway.

I suppose if I put a free flowing pipe and filter then used the EJK to richen it back up to 12.5 or 13 then it wouldn't get as hot as I found with the O2 eliminator but then I'd be forever faffing with the maps and logging the temperature and messing with the O2 feedback - with my obsessive personality I'll give it a miss and run it standard (cam timing notwithstanding)
12/07/2019 11:28:08 UTC
Ren - The Ed said :-
I find it fascinating reading this. If this had been on the old carburetted machines all you can do is best-guess the mixtures based on experience and "feel". Today you two seem to be capable of accurately calculating what the computer is up to and, if you wish, manipulating this in a repeatable manner. And they say FI is far too complex.

Bearing in mind Sharon'w Z250SL which shares a lot (but not everything) in common with Bob's KLX I'd be curious to know what hers is up to. But only curious. It is working, it works well, it returns 90mpg and more and Sharon is happy. I think it more than just wise for me to leave well alone for now.
12/07/2019 01:54:04 UTC
Ian Soady said :-
It's actually much easier, once you have the software, to tweak the maps using a laptop than it is to swap jets, do plug chops, swap the jets again..... Yes there's a learning curve but once you get to grips with it essentially you're just looking at a spreadsheet, and there's lots of information on dedicated websites. Of course there's lots of misinformation as well.

Essentially those maps show throttle position on the Y axis and rpm on the X. There are other tables which deal with ignition advance as well as mixture correction for temperature but I never touched them.

When I was working on the Tiger, I started with someone else's map then adjusted till it felt right. As long as you don't go silly there's not too much harm to be done. And what I ended up with wasn't actually a million miles from where I started, the key point was eliminating the closed loop running. The advantage over using a power commander or similar was that I was using the ECU itself to effect the changes rather than something plugged on afterwards trying to fight against it.

Actually a lot of people did have success with simple O2 sensor eliminators on the Triumph but I preferred a more (to me) sophisticated approach.
12/07/2019 03:00:16 UTC
Bob said :-
Now, if I just had a rolling road, an exhaust gas analyser, a programmable ECU and a broadband O2 sensor I'd be sorted.
It's interesting that the solution for your Trumpet was to eliminate closed loop control. I think many of the fixes and mods that we see are along those lines.
I was surprised to see the effect on engine temperature when I was running the KLX in open loop (using the O2 eliminator), this also shows that the Keihin EFI system used on the KLX uses closed loop control most of the time, excepting the widest of WOT.
12/07/2019 10:30:35 UTC
Bob said :-
I'm getting the hang of this now.
My KDX200 snorkel arrived from Cradley Kawasaki - this is a well known power mod on KLX250s.
I put the DVM back on the O2 sensor and went out.
Wow, what a difference! Much better performance throughout and pleasingly increased torque on the mid-range.
The O2 sensor confirmed that the ECU has adjusted for the new snorkel, on WOT the voltage was well above 900mV and after a right royal thrash I didn't notice any excess heat and my Healtech diagnostic says 89C for the coolant temperature.
Lovely jubbley!
13/07/2019 04:40:35 UTC
Ren - The Ed said :-
So what's the difference between the 2 snorkels?
15/07/2019 07:37:21 UTC
Bob said :-
The KDX snorkel has an inlet that looks at least twice as large in terms of area and it is also much shorter. The bike is unusable with no snorkel, it is far too loud. With the original snorkel there is no discernable inlet noise, with the KDX snorkel there is some inlet noise apparent but now it just sounds like a bike breathing properly.
I wouldn't have said the bike felt like it was struggling for breath with the original snorkel, until I tried the KDX snorkel - it's a very much happier beasty now.
15/07/2019 08:16:56 UTC
Bob said :-
I've just returned from another 4 day, 700+ mile trail riding trip in North Wales.
As 1 year of ownership and 12500 miles ridden approaches I thought I'd share my experience of long-term (long-term for me at least) ownership.

In the year I've run the bike the faults have been:
- Chafed wire on the ECU multi-way plug, this is a known fault on early bikes where the loom rubs on the frame. It manifested as fluttering on the secondary throttle butterfly stepping motor. Rectification involved chopping out and replacing the chafed wire and re-wrapping the loom
- Bad connection on the coolant temperature sensor. It manifested as variable tickover, racing up and down. The fix was to clean out and degrease the connector.
- Bad camchain tensioner. Obvious from the loud slapping noise on the right hand side of the barrel. The bike was like this when I bought it. It is very common on KLX250s the fix is to fit a Krieger manual tensioner, I did this and I've had to adjust it only 4 times in 12500 miles.
- Fork seal failure. I put this down to trail riding, easily fixed and I added gaitors to keep the grit out of the seals. The seals have been fine since then.
- Gearbox O/P seal leaking, easy to fix on the KLX as there is a removable sleeve over the O/P shaft, it could be done by the roadside if necessary.

I've also had the odd indicator bulb blow but I don't count that as a failure of the bike.

It has never let me down out in the field and I have ridden some pretty knarly trails through deep water and dropped the bike several times.

The bike continues to be an utter joy to ride, perky and fun with a furious engine characteristic (in it's tuned form) and stunningly capable off road.

It now has 25000 miles on the clock.
Posted Image
02/10/2019 08:05:26 UTC
Upt'North said :-
Bob, very nice looking Kwaka 250.
Id love to thrape that across a beach or two.
02/10/2019 10:02:08 UTC
Ren - The Ed¹ said :-
I'm glad to hear the Kwakker 250 is surviving your abuse Bob. Sharon's similarly be-engined but not tuned or abused so much Z250SL has only required the basic maintenance at 25,000 miles. I reckon it'll be due a tappet check soon though.
02/10/2019 02:10:07 UTC
Bob said :-
I would make it clear that any abuse the bike has suffered is within it's design remit - it is a trail bike after all.

I do look after it though, in the year I've owned it it's had:
12 oil and filter changes
Swingarm, suspension linkage and headstock bearings greased twice
Fork oil changed three times
Two spark plugs
Air filter cleaned three times.
Valve clearances twice
Coolant changed.

I would say you definitely should check those shims. I did them on this bike at 13000 miles and now at 25000 I've had to re-shim one exhaust valve again. If they've never been checked on the SL I'd get in there quick.
I bought a Hotcams shim kit off the Evilbay, £79 I think it was - money well spent to have all the sizes you need in one box.
02/10/2019 07:40:34 UTC
Ren - The Ed¹ said :-
12 oil changes...!!!...???...!!!

Sharon's shims were checked by the shop at 8k as it was still under warranty. We did them at about 16k. At 24k they'd be due again. However once a bike has bedded in I am of the opinion (and it is just an opinion) that I don't need to be quite so strict with the checks.
03/10/2019 09:04:46 UTC
Snod said :-
My Z250SL is over 19K and I haven't reshimmed it yet (not checked for about 10K or so), this is making me nervous..
03/10/2019 08:07:59 UTC
Ren - The Ed¹ said :-
Chill Snod, if it was OK at 10k it won't be far out now. It is due a check though so give it the once over.
04/10/2019 08:51:45 UTC
Narong said :-
Hi Bob, could you give me the Sargent Seat measurements/specs?
Thai Seat Magician is gonna make me one for a few bucks...
10/10/2019 03:33:11 UTC
Bob said :-
It's 280mm wide at the widest part. It's 40mm thick. The problem you'll have is that the Sargent saddle uses a different moulded seat base, which is wider to accommodate the wider foam.
Seatconcepts do a kit which has new foam that fits onto the standard base, but it's not as wide as the Sargent.
Posted Image
11/10/2019 08:22:18 UTC
Narong said :-
I see... What about the side of the seat. Is it straight vertical or even bent a bit outside?
Thanks for the measurements. Also is the foam softer or more firm?
04/11/2019 11:44:05 UTC
Narong said :-
And the last question. The seat-contact surface looks slightly bent. Is that true or flat?
04/11/2019 02:02:18 UTC
Bob said :-
The sides of the seat slope outwards and up at the back, the sitting part is wider than the bike's frame.
The sitting area is slightly dished, so it feels a bit more like sitting in rather than sitting on the bike.
The foam is very firm, but I find that's usually best for long distances - soft foam seats feel good at first but after many hours the foam compresses and you end up sitting on the hard seat base.
The best £340 I ever spent on a bike - I can't stress enough how different this is from the original torture device that Kawasaki fitted!
04/11/2019 05:14:36 UTC
Herb said :-
Hi Bob just trying to clear something up here at the top of this article you say RETARD the inlet cam 10 degrees and then further down the diagram clearly says ADVANCE the timing so which one is it ?????? slightly confused (only about that)but otherwise a great read mate
Posted Image
08/07/2020 09:43:16 UTC
Dave said :-
I agree the KLX stock seat is horrible/un-useable. I see many guys going with the Sargent, and all shudder at the cost. (aprox. $430.US). I've compared the Sargent and SeatConcepts seat side by side and couldn't call either one more comfortable than the other, and saw no quality difference. Personally I feel the SC seat is more attractive, offers more fabric options and is much cheaper ($175.US) if you buy the foam/cover kit. Mine was a first attempt at motorcycle upholstery and turned out perfect. Took about an hour in no rush. Seeing as how most guys reading this will do cam timing mods themselves, why spend so much on a seat???
Posted Image
10/08/2020 11:08:57 UTC
Ren - The Ed¹ said :-
Well it looks very smart Dave. You say "foam/cover kit", I'm guessing you receive a new piece of pre-shaped foam padding and the cover? You remove the old cover and the old foam and fit the new items?
11/08/2020 08:45:14 UTC
Upt'North said :-
Nice work Dave. The top looks anti slip?
I also think some of the seats out there are ridiculously priced.
I think riding discomfort is part and parcel of motorcycling. Yes some seats, like our own rework, may help on comfort but sitting on your arris for long periods can cause discomfort, it's a fact.
But who said motorcycling was comfortable.
Hell, someone on here rides his bike for,
Long periods.
Then cooks his own dinner.
Then sleeps on the ground.
Then does it all again and again.
He likes it too!
If you're in the States Dave, whereabouts are ya. I promise not to call unannounced. Maybe.

11/08/2020 09:36:48 UTC
Ren - The Ed¹ said :-
What kind of fool on here likes to do the things you speak of Upt'?
11/08/2020 10:11:39 UTC
Paul said :-
Great review Bob, relevant and direct without any BS. Top read!
If I'm reading it right you have confirmed most of what I found myself.
My KLX250 came with an aftermarket exhaust and O2 eliminator. I didn't ride it before buying (threw the dice), I then found out that the fuelling was horrible. It was snatchy and hesitant off the bottom and hunted at tickover, it was only really rideable with the throttle pinned - not only that but the exhaust was wayyy too loud for trail riding in the UK. (I'm a trf member and noise on the trail is a big reason why we have been targeted for extinction by ramblers and nimby's)
I returned everything to stock, buying a standard exhaust, and refitting the O2 sensor, and what a difference! The bike is now smooth, quiet, and actually feels more powerful. The only mod I've done is linking the clutch sensor, but may well do the inlet cam mod soon (did you take the spring off the exhaust decompressor as well?).
I also have the Kreiger cam chain tensioner. I am wary of running too much tension, as a result, on startup I have a little cam chain slap which goes away when the bike warms up - is that your experience? Or would you recommend that I give it a 1/4 turn or so more?
Great thread (for KLX'ers) I've bookmarked!
22/08/2020 01:23:15 UTC
Mitch said :-
Bob. You said you liked the bike better with just the inlet modified and not both inlet and exhaust. Can you give a discretion of how the bike handled differently between the two?
27/09/2020 05:46:40 UTC

Post Your Comment Posts/Links Rules



Add a RELEVANT link (not required)

Upload an image (not required)

No uploaded image
Real Person Number
Please enter the above number below

Home Bike Reviews

Admin -- -- Service Records