Gear problems on Honda CM 125 Custom (with history)

[hannadarling]

Hello everyone again, Ive stripped the engine down, alot of bits have snapped off the gear box including the spring, not only that, The left hand side piston has kind of seized!
No free play what so ever, cant even get the piston off!
Ive had to saw it in half lol
So now I'm looking for a new engine as this one is nackered! Well I just want less hassle anyway.. And would save me money in the long run..

Does anyone know any sites where I can buy an engine for this kind of bike?? (Honda CM 125 Custom, twin cylinder, 4 stroke)

Ive looked and looked but maybe I need the right sites to get one?

Thanks

Hanna

[Piercee100]

I'm not 100% sure but I think you could use a cd185 / cd200 engine with your top half to create a 125? Or maybe swap for a cb125t engine which has twin carbs and more complicated electrics but I believe make decent power.

I've often wondered whether the simple CG125 engine would bolt into these frames and the sprockets line up? Simple engine with loads of easy and readily available parts... And would also mean you could fit a new chinese copy engine for about £200 if you wanted a new lump.
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Rides: Honda H100a (Retired), VT500e (Sold), Kawasaki ZX400 (sold), Kawasaki GT550 (Sold), Suzuki Inazuma (Daily), Honda CD185t (Broken), LML Star 2t (Last run edition).

[doombug11]

Finding a replacement engine for one of these is a bit of a shitter. They appear on ebay every now and then, I got one of Gumtree last summer. Most other little honda twins should bolt in (CM, CD, CBt) Though you need to sort out lining up the sprocket and getting the electrics working which can be a pig.

CM 200 and CD 200 engines are quite available and slip straight in, but if you need to keep it 125 you may do well finding a donor bike going on ebay, they sometimes go cheaper for what some breakers will charge you for the engine.
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1999 CBR900RR, 1984 CM200 (previously 125)

[hannadarling]

[doombug11]

The CM200 should go straight in, and the sprockets should line up. The CD200 also bolts in but you will need to get a 10mm off-set sprocket made up to align it with the back wheel. With both ideally you want the later 12v version as these will work with the electrics already on the bike. You could convert to 6v but its a lot more work.

I've converted my CM with a CD200 engine, it needed the sprocket made up and the carb (I used the 125 one) needed the jets changed. The wires are identical but have different connectors though that was easy enough to splice together. Aside from needing a slip-on air filter because the manifold has a steeper angle on the CD engine that's all that was needed to get the 200 in. Makes the bike a lot more fun too, even more wobbly but much more usable.


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1999 CBR900RR, 1984 CM200 (previously 125)

[Teflon-Mike]

Note that there are different versions of CM250. Earlier ones were cruiserified variant of the CB250 Super-Dream with the counter-balence 'big-block' engine sleeved down from the CB400N. These will NOT fit 'Benly' engine bike frames, without adaptation. So be very careful what you buy, if you want it to fit your frame.

Note also, that NONE of the Benley family engines is hugely powerful; the 234cc motors used in the CD250U, CMX250 and CB 'Two-Fifty' barely make 20bhp; the 200's only make about 15bhp!

Though peak power is only half the story; even the 15bhp 200 engine, has quite a pleasant amount more low-down and mid-range power, even if it dont make the bike any faster. Also has 4-speed gearbox reputed to be quite a bit stronger, which may appeal to you

Have you spotted this?

CD200 benly bits in for Sale section, by salem1987? He looks to be up in your quarter of the country too.
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My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[hannadarling]

Thanks for all the info and help guys!
My plan is to get a good working or if I'm very very lucky a reconditioned 200 CM engine in, Sounds alot more easier, well time saving aha

Excellent idea I think

I'll be intouch when Ive got one

Thanks for the link though Teflon Mike, is there any more info I need to do the swap for the 200cc engine? Or is it just the 12v I'm looking out for?

Thanks guys

Hanna

[hannadarling]

[Teflon-Mike]

[hannadarling]

[Teflon-Mike]