Looking across to the snow capped alpine mountains seen from the back seat of a motorcycle

Home Repair And Restoration

State Of The Swingarm Address

Bodge Date Early August 2020

By Ren Withnell

Play some pompous patriotic music to suit your country/county/beliefs. Give everyone an appropriate flag but in this case make it somewhat dirty. Now imagine me standing at a lectern while I address you and your family about that which really truly matters. My 125 Swingarm. 

Ren standing on a wall in the rain
Far more Presidential than Trump, better than Boris at bumbling. 

The CBF 125 is known to have issues with rust on the swingarm and the frame around where the swingarm attaches. The old CG125s and even Bogger's Innova have similar issues too. This is due to Honda using basic plain steel materials in an area where water, muck and worst of all winter salt abound from the rear wheel.

This area is also quite inaccessible, seldom seen and difficult to clean. As such it is oft neglected so quietly, secretly and surreptitiously corrodes away until an MOT inspector spots it or the rear end takes a dive. Hopefully the former and not the latter.

My own CBF 125 has been casually inspected by myself over the years. A prod with a screwdriver, a cursory glance while doing battle with the perpetually rusted in place centre stand or even a random clean on one side while fitting a new chain. But after Bogger's swingarm restoration on his Innova this potential problem has been niggling me.

So dear reader, I must gird my loins, brace myself, stiffen the upper lip and prepare to do battle. I'm going to do it. I'm going in. I - Ren - The Ed - am going to, ahem, CLEAN the swingarm and the frame around the swingarm mounts. If all goes well and I survive this intrepid adventure I expect I shall receive at least an MBE if not a knighthood for services to motorcycling.

Armed with spanners, screwdrivers, a litre of diesel, a hosepipe, several toothbrushes (used) and some sunshine I venture in. There is much poking and prodding. There is a growing mound of oily dirt. New oil-based life forms are found and recorded. New discoveries are made ("oh so that's how the brake torsion arm is mounted"). A few parts are removed. 

There follows much scrubbing and hosing then more scrubbing and more hosing. By the end of the first day much is exposed and I, well I look like a cross between a coal miner and an oil rigger. Tonight I are be mostly having a shower and smelling of diesel. Even after the shower myself and my house smells of diesel. Luckily it's a good smell.

Over the next few evenings I poke and prod, clean and scrub until the swingarm is revealed in all it's glory. While it is far from a pretty sight I am more than pleased to find the rust is merely surface rust. No great flakes or chunks come off. No holes are found. everything appears structurally sound. 

Light surface rust on the top of Ren's swingarm
Rust, yes, knackered, no.
The underside has less rust but some flaky paint
Flaky paint isn't structural.
The left arm's pain it missing but the rust isn't serious
No holes no missing chunks.

This is of course a great relief. This also reinforces my belief system. The best way to prevent rust on a motorcycle is NOT through careful, regular, thorough, boring, tiresome cleaning but by ensuring the bike has a protective layer of oily crud. 

Of course creating a protective layer of oily crud takes a great deal of time and dedication. In the meantime I don't want all the newly exposed metalwork to rust. I have a tin of Hammerite Underbody Seal. Within is a waxy, oily, bituminous, gooey substance. I slobber great goops of this delightful viscous black snot all over the newly exposed areas and leave it to dry. It never actually dries completely but it does "go off" a bit. 

The underside of the swingarm is covered in thick black tar like goo
Now THIS is my kinda paint (ie not paint).
The top of the swingarm treated with the underseal
Ohhhhh yes. Sticky, tacky, gooey and thick.
The left swingarm covered in more underseal
Reminds me of "Vandal Paint"

Finding the swinarm and surrounding areas in fair condition is a relief. In a fit of "joie de vivre" I also fit a new front tyre and go for a long ride to celebrate.

How does the CBF 125 thank me for this tender love and care I have given it? How do you keep an idiot in suspense? I'll tell you later.


Advertise here? Contact ren@bikesandtravels.com

Reader's Comments

Bogger said :-
OMG. Just give it to me and I'll get it sand blasted and painted for you (FOC.... your type of price). Heavens above man.

Bogger
21/08/2020 10:05:08 UTC
Upt'North said :-
Well done Ed, jobs a gud un.
Bogger, your offer is obviously commendable, well done sir, but I think the rest of the bike would reject it like an unmatched kidney transplant.
Upt'North.
21/08/2020 10:23:02 UTC
Womble said :-
Well what can you say! Is it fair to say you spoil that bike.
21/08/2020 11:22:49 UTC
nab301 said :-
Quote Bogger " Heavens above man." I can only agree ! Sure the swingarm nearly fell off a while ago , could you not have removed it ? , Take up the offer of a free refurb ! and failing that, before you coated it in that bituminous crap you could have used a scotchbrite wheel to remove the loose rust , then etch primer and aerosol stonechip coating covered with a top coat ....
MBE = menber of botchers eclectic ?
Nigel

21/08/2020 11:32:17 UTC
Ren - The Ed¹ said :-
Jeeeez folks! You are a hard hard crowd.

Oh no, no no credit at all. No "Blimey Ren, for 90,000 miles and 11 years old that swingarm sure is in good nick". No "Cor, makes me wish I'd not wasted all my life just cleaning a bike rather than riding it". Nothing like "Well done sir for taking on what was obviously a huge challenge both personally and practically.

Noooooo! No, you 'orrible lot just lay into me for not making it all nice and pretty and shiny. No, just because it doesn't meet your exacting standards I'm a plonker!! Well I'm going home and I'm taking my toys with me! NER! That'll teach em.

"the rest of the bike would reject it like an unmatched kidney transplant." Oh my that did make me laugh though. And thank you Womble. While I suspect your comment was satirical in nature I choose to see it as a compliment.

Just you lot wait... wait and see the botch job I'm doing on the motor!!
21/08/2020 01:58:35 UTC
Bogger said :-
Well I suppose credit where credit is due.

But there is none so you ain't getting any.

Err is that overstepping the mark??

Regarding the engine. Are you re-profiling the camshaft with an angle grinder? Re-boring it with a house brick perchance? Or something far worse?

Not bothered, it's not my bike, just asking like

Oh, keep up the good work by the way.

Bogger
21/08/2020 02:41:38 UTC
Rich said :-
Mine was already pitted with rust when I got it at 9000 miles! It got some rust treatment and hammerite which seems to be lasting well. My swingarms out today to get some paint on the back half of the frame.

A little semi-related question, when I tighten up the swingarm pivot to spec the inner part of the bushes tighten against the frame and footpeg hangers. It feels like the pivot is coming from the rubber part of the bushes twisting and gets progressively firmer when you lift the swingarm with the shocks out. Does that sound normal? My other bike has roller bearings and moves freely.
Cheers
Rich
21/08/2020 02:47:39 UTC
Rich said :-
Mine was already pitted with rust when I got it at 9000 miles! It got some rust treatment and hammerite which seems to be lasting well. My swingarms out today to get some paint on the back half of the frame.

A little semi-related question, when I tighten up the swingarm pivot to spec the inner part of the bushes tighten against the frame and footpeg hangers. It feels like the pivot is coming from the rubber part of the bushes twisting and gets progressively firmer when you lift the swingarm with the shocks out. Does that sound normal? My other bike has roller bearings and moves freely.
Cheers
Rich
21/08/2020 02:47:42 UTC
Ren - The Ed¹ said :-
I'm not absolutely 100% sure... but I think it's fine. See on the smaller bikes Honda used rubber bushings as opposed to expensive bearings. To be frank in the 90K I've had my CBF125 and the roughly 70k I did on the CD200 Benly that had rubber bushing, they never caused issue.

I would expect the swingarm to tighten at the top of the stroke as they are rubber bushings without movement save for the twist in the rubber. In fact be careful not to over-rotate them for fear of ripping the bushes. I'll go check the manual now to see if there are supposed to be washers or some other spacers between the swingarm bushes and the frame...
21/08/2020 03:01:18 UTC
Ren - The Ed¹ said :-
Nope can't see any on the diagrams for my year... Also can't see those bushings as a separate item either so erm, don't over-rotate them!
Posted Image
21/08/2020 03:04:05 UTC
Ren - The Ed¹ said :-
Bogger, rebore with a brick! Where am I gunna get a brick that small? No mate don't be silly, I've used a stone superglued onto a drill bit, durgh. Is a piston ovality of 3mm acceptable? Meh, It'll be reet. As for the cams I'm using JBWeld to build them up a bit. Not 100% sure about the cam chain either so I've adapted one from a bicycle (many a true word...).


21/08/2020 03:14:17 UTC
Rich said :-
Cheers! I couldn't see any missing parts on the diagram on Fowlers parts website. Yes they expect you to replace the whole swingarm! I did see some non honda bushes on eBay but I would think the old ones are well rusted in on mine. I think I'll torque it up with the back wheel on the ground so it has less for the bushes to rotate if that makes sense.
Thanks again!
21/08/2020 03:36:42 UTC
Ren - The Ed¹ said :-
Ahh yes I see what you mean. Start the bushes in their most "relaxed" position. To be honest while the rubber bushes might not offer the pin-point accuracy and taughtness of needle rollers... they don't need looking after either.
21/08/2020 03:49:59 UTC
Bogger said :-
Rich the swing arms do get 'tighter' further up the travel due to the bushes being tight. It's normal.

Bogger
21/08/2020 04:01:07 UTC
Rich said :-
Cheers Bogger good to know
21/08/2020 04:36:31 UTC
nab301 said :-
On the swing arm bushes the only other bike I have with a similar set up is my Enfield Bullet . Enfield actually produce a flat rod of the correct length which is bolted to the upper shock mount and the swingarm mount before the swingarm pivot is tightened . The manual suggests that position is mid stroke .
Nigel
22/08/2020 10:41:07 UTC
Marv said :-
If you ever take the rear wheel off, it's not that many more bolts to release the swing arm. I ground off the rust and painted on a layer of black paint, and some stone chip protection on the arched shaped bit on the inside. Sadly no "after" pics.

Honda don't seem to put any grease on the swingarm bolt, so that's a good time to apply some.
Posted Image
23/08/2020 10:30:59 UTC
Ren - The Ed¹ said :-
No before and after pic Marv?! Good heavens! You are quite right if the rear wheel is out there ain't much more to do to release the swingarm on the CBF125. And it's a good call to grease the grease the bolt, hand't thought of that.
24/08/2020 07:42:08 UTC

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