Camchain and tensioner seen up close in a cutaway bike engine

Home Repair And Restoration

CBF125 Servicing - Again

Job Date - Thursday, November 28, 2019

By Ren Withnell

I cannot honestly remember if I did the tappets on the 125 at 80,000 miles. Which means it's possible, likely even, that they've not been checked for 16,000 miles now. The recommended service interval is 2,500 miles - ahem.

This being November the weather is ideal for working on a motorcycle in a cold shed as the light fades at 1600 hours and the rain rattles on the tin roof. Luckily I have done this task a few times before so it is no longer a daunting prospect. 

I arm myself with my trusty Halfords Professional toolkit, a cup of tea, several torches, many warm layers and a plenty of rags. Off comes the back seat, then the front, then the side panels, then the tank (at which point my dirty floor gets a jolly good clean from spilt fuel) and then the rocker cover. 

Ahhh there you are, my long suffering valve train, good to see you. I'm pleased to see that you're looking well, you have a lovely tan, a nice oily layer and there's no sign of milk (emulsified oil) any more. Now, bear with me a while as I set the bottom end to Top Dead Centre. I can feel you have just a smidge of freeplay there? But is it the right amount of freeplay? I've forgotten my feeler gauges, give me a moment.

The engine has the rocker cover off showing the oily and light brown tappets
Simple valve mechanism on the CBF125 

0.08mm in and 0.12mm out is what it should be. I can get the feelers into both gaps but they're just a tiny little too tight. Considering they've not been checked for 16,000 miles that's excellent, or, erm, did I check them 6,000 miles ago? Oh hell I don't know. Look, it doesn't matter, I have checked them and adjusted them now and that is what really matters. 

While looking around I notice a significant amount of flaky paint and rust under where the rider's seat and the airbox is. Rust is a known issue for the CBF125 frames and swingarms, but this is usually around the lower part of the frame where the swingarm is mounted. 

Mine has some initial corrosion around that area but my lack of cleaning and regular use means the protective layer of crud and old engine oil is doing it's trick. Here under the seat where I seldom venture things are different. It's still comparatively clean and there is a distinct lack of oilyness. Combine that with a life of riding in the rain and damp northern conditions and here we are. 

The remedy? I have a tin of spray grease, fork lift truck chain grease to be exact. I give the whole area a dose of wet grease that should dry out and collect any passing dust and dirt nicely. 

The frame under the seat is covered in spray grease to hopefully stop the rust
Just squirt the rust with spray grease. Sorted.

I give the air filter a blast out with some compressed air. I've owned this bike for 7 years now, I wonder if I've ever replaced the air filter? I have I think, but lord knows how long ago that was. Maybe I should treat it to a new one? One day, maybe, perhaps.

I'm not changing the oil. There's just over 1 litre in there that should last 2,500 miles. It drinks more than 1 litre in that time, it's more akin to a 2 stroke these days. I'll probably change it at 90,000 miles to remove any sludge that'll be collecting at the bottom of the motor. 

It has tyres with tread - check. Pressures - check. Wobble all the bearings - check. Brakes - check. That'll do for now. I must remember to make a note that I have checked the tappets. 

This poor bike. If it were a horse they'd have shot it out of pitiful mercy, and yet it continues to function. While it looks like a dirty old mistreated mongrel it still rides just fine. Alas nothing can last forever and something, somewhere, somehow will decide enough is enough and throw in the towel. That will be a sad day for me.

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Reader's Comments

Snod said :-
Looks perfectly fine to me but how's the gearbox holding up?
29/11/2019 09:19:14 UTC
Ren - The Ed¹ said :-
The gearbox feels fine. It is prone to jumping out of second back into neutral just when you're trying to impress a lady on your butch manly powerful 125, but that's as much me being too fast with the gears and clutch as the box wearing out.

I replaced the clutch a while back, it's reported on here.
30/11/2019 07:34:38 UTC
Borsuk said :-
Just be glad it is only your bike jumping out of gear Ren. I`d hate to be you if Sharon caught you trying to impress other ladies on your 125.
I can see your gear lever doing movements it was never designed for.
01/12/2019 11:10:27 UTC
Ren - The Ed¹ said :-
There once was a time when Madam Parker would have gouged my eyes out for looking at other ladies. Alas she has come to realise I am an old has-been and no matter how much I try to impress the ladies on my butch manly 125 I have more chance of winning the lottery than I do of actually "pulling" - and I don't even purchase a lottery ticket.
02/12/2019 03:22:18 UTC
Borsuk said :-
I`ve been winning the Euro lottery without buying a ticket for years. At least according to the emails I get offering to process my winnings for me after I pay a nominal fee of 400 euros or so.
For some strange reason my email program insists that these emails are spam, wonder why it thinks that.
03/12/2019 12:35:32 UTC
Ren - The Ed¹ said :-
Ignore those emails Borsuk, I'll process your Euro Millions for just ?399
03/12/2019 03:56:11 UTC

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