SL / CL Bitsa bike Overhaul

Here's my current project: An SL / CL Honda 125/100 'bitsa' bike that I've owned for ~17 years. It's made up of an early 70s SL125 chassis (with fenders and headlight/speedo from other old Hondas), a '72 CL100 motor, XL100 exhaust, sidecovers off some old 400 Yamaha, etc. I built this when my 1st son was a baby and he graduates high school this year. I used to take him AND his little brother around the trails around our neighborhood. So, now the motor is just tired, making lots of rattles and clacks and not wanting to go much over 35 mph blowing lots of smoke along the way. I figured it's time to give the ol' motor an overhaul.

It USED to pull me around at up to 50mph, so I thought I might refresh the motor and see what kind of mileage I get on my daily 12-mile 45mph in-town commute.

So, yesterday I started disassembly. Got the motor out on the floor in just a few hours of not-very-intense, holiday-week work.



So far, just a lot of sludge and some wear. Not too bad for 37 years old. So far, it'll need new camchain tensioners (which I think I have leftover from another project some years back). And, it'll need rings and/or piston. Haven't gotten that far to measure yet. Maybe new clutch plates. And just lots of cleaning and de-sludging. Maybe even some cosmetic refurb - polishing stuff, etc.



Anyway, that's what I'VE been tinkering on....



Hey! Good luck on your project. I just started a 1975 TL125. I've got an end play in the crankshaft - case problem that I don't know how to deal with. Guess it's time for new cases. Just had a re bore job on the cyl. finished & found a new piston & rings. I"ll get it running good & then start the cosmetics. Parts are hard to come by!

Gaaa! Got the top end off, and started into the clutch side. Got to the point of needing to get the oil slinger assembly off, and can't find my MotionPro tool.... >:-(

Sheesh. If if isn't one thing, it's two... :excuseme:

Oh well, I'll keep looking. Or, might just make one from a cheapie socket cut down. Hate to buy another one for $10. I hate to pee away another $10.

How did the SL100 hop up work out?

I sold my SL100, too many projects.

I still need to rebuild my TL125 (after many other projects.)

How well did a XL 125 head fit on the old SL cylinder?

Did you have to customize the cam chain guides?

I have the TL125 motor in questionable shape.

And an XL125 non-running motor I bought on eBay.

Between the two, I hope to get a running motor. (or two).

Might try a PM,, beings this is a 2 year old thread i'm not sure if he is still around?..

Showtime45. This winter I did the top end on my sl125 and when I took the cylinder in for boring I asked the mechanic (who has been in business forever) about crank end play. He said it's normal unless its a ridiculous amount. I put mine together and it works fine.

OOps. forgot to check the post date.

Hey, I guess I forgot to post back with the results - forum overload, 'cause I DID post results elswhere... Sorry.

Rather than post it all over again, the above thread on the Vintage Japanese Motorcycles Owners Group forum posts it all, right up to the successful end.

So far, I've got over 1000 miles on the rebuild. Running great and getting 90 ~ 94 mpg!

As for the head swap - this was an early, one-piece head so there are no interchange issues at all. The problem crops up in trying to use the later, two-piece heads. They swap, but the 2-piece head's cam sits closer to the deck surface, so you need to use the shorter cam chain and shorter tensioner pieces from the later models, along with the 2-piece head.


Thanks, I read your other thread.

Is there a list of items that typically need replacing on an SL125 rebuild?


Piston/Rings/Cylinder rebore, Gaskets


Cam chain? Sprockets? Cam tensioner?

Valves, Valve guides?, Valve guide o-rings?

I guess I need to pull out the manual and caliper. I don't have a micrometer.


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