2001 cg125 engine into xl125 1976 frame is it possible

[Holadog]

I have an xl125 1976 and wondered if I can fit cg125 2001 engine with electric start in it. Any advice please.

[Teflon-Mike]

Why would you want to?

AFAIK most of the small honda's share a common bolt-pattern, derived from the original OHC single used in the, CB/SL 125 single of the early '70's that went on to be evolved into the OHC lump used in the, oooh... XL125, CB100, CB125RS, and many others.
The CB125 'twin' was derived of that motor, and shares frame mounts, as was the push-rod CG engine, retro-engineered for lower maintenance (and performance... sort of an engineering limbo exercise), for developing country markets to compete with the vertially no-maintenance two-smokes.

So, a CG motor 'aught' drop into an early XL frame, bolt-for-bolt, easy as pie.... it's pretty much what Honda did to make the later XR125 road bike....

Problems, might arise around the exhaust and carb/air-box, but most head scratching will likely be found trying to match the electrics.

Old XL125 was 6v points, later model CG's were 12v CDI ignition. Some ingenuity will likely be required to match the wrigglies and make stuff work.

Plenty of bits available on the bay and in the scrap-yards, and plenty of interchangeability, its eminantly do-able... but not necesserily the most easy... and btt... other than CG's and clones being three a penny, why would you want to degrade an EX that probably had around 12bhp, with a motor that at best, likely only makes about 10?.

There's some sense in doing it for an every-day rider, to make it that bit more every-day maintainable with more easily obtained bits.... but as a genuine forty odd year old classic? Turning it into a hybrid would rather throw away much of its classic worth and value, as well as oomph... and 20% on a bike that struggles to NSL is a lot to sacrifice...

But, your call.
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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?'

[Nobby the Bastard]

Ooooh, a good hard teffing as the first reply to your first ever post.

My commiserations. If its any consolation, it was only a quarter of the standard teffing.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[WD Forte]

Possible?
Yes of course
I'd do it
A good working 2001 CG lump trumps a knackered 1976 XL one
anyday of the week
12 Vs 10bhp?
I doubt you'd know the difference
Classic my arse but there's no reason you couldn't do it in such way as to make the process reversible.

It aint rocket science, pretty straight forward in fact,
the only caveat is the mechanical and electrical skills of the modder.
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bikers smell of wee

[blurredman]

I had an XL125 from 1978. Which had a same period CG engine put in it. Either that or the electrics were swapped back over for 6v. Anyway.. The only problem was lack of 6th gear that the XL125's have meant it barely topped at 50mph. I didn't think much of it. I presumed someone had blown the original engine up in the past. Which wasn't a surprise given it was such an old '125'. As I could see, the mounting locations were identical.

This is a picture of what I had.

https://cloud.leparking-moto.fr/2018/04/26/02/55/honda-xl-honda-xl-125-s-1983-moto-e-scooter-usato-in-vendita-pesaro-e-urbino_86761663.jpg
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CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S.
Current: 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (bored to 295cc) - 38k, 1990 MZ ETZ251 - 49k, 1979 Suzuki TS185ER - 9k, 1973 MZ ES250/2 - 17k.

[bladerunner]

wont notice much difference between 12 and 10hp....you'll bloody well notice a 20% drop in power for sure but then again I suppose you can drop a 160cc kit and carb on the CG motor and all is good with forward progress again
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[steve the grease]

The old cb/sl/xl 125 OHC engines used to wear out the cam bearings in the head in no time at all. which is why they are all knackered. like the guy said a good cg beats a knackered XL any day

[terrytibbs]