Fungus
Part of things
Posts: 960
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Sept 27, 2009 10:02:45 GMT
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Hi everyone, i have been thinking about an engine conversion for my '78 cg125. This is mainly because they are apparently un-tuneable!  i was thinking of a cd175 twin, because i have access to a seized one to mock up, and then buy a running one. As for other suugestions, i would like to keep it Honda. Ideas are welcome! |
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Mr S
Posted a lot
10-4 Good buddy.
Posts: 2,654
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Sept 27, 2009 10:08:09 GMT
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If it's a tuneable engine you want, I'd suggest an oil cooled GSXR110 engine... You might want to brace the frame and update the running gear a bit too tho! lol
Personally I wouldn't want to go much faster on a CG125 than the standard engine allows - what with it having fairly poor drum brakes and all...
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Suzuki GSXR1000 K2
BMW R1150GS
BMW K1200RS
Chevy K5 Blazer
Chevy Suburban LT
Jaguar XKR
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Fungus
Part of things
Posts: 960
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Sept 27, 2009 10:10:38 GMT
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I do see what you mean about the drums! I was thinking of using later forks/front wheel (discs). A GSXR110 would be good though! But arent they a bit pricey being new and all. I was hoping to keep it looking almost like the engine should be standard by going with an older one. Thanks for the Idea though!
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Last Edit: Sept 27, 2009 10:14:07 GMT by Fungus
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Mr S
Posted a lot
10-4 Good buddy.
Posts: 2,654
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Sept 27, 2009 10:13:04 GMT
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Good man! In that case, something like a Honda CD250 single might fit in reasonably ok, I think they've got just less than 20hp so would be a fairly healthy boost without going daft, shouldn't be much heavier too - from what I remember the CG does handle nicely and you don't want to upset that with a heavy wide engine!
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Suzuki GSXR1000 K2
BMW R1150GS
BMW K1200RS
Chevy K5 Blazer
Chevy Suburban LT
Jaguar XKR
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Fungus
Part of things
Posts: 960
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Sept 27, 2009 10:16:00 GMT
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Thats sounds pretty good. I'm guessing they can be tuned a bit too, although you do have a point about not going daft lol. i think 20hp is just about perfect!
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Mr S
Posted a lot
10-4 Good buddy.
Posts: 2,654
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Sept 27, 2009 10:18:14 GMT
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If you really wanted to tune it, you'd be better off going for a 2-stroke I imagine - plenty of small 2-stroke 125s that are tuneable (although they'd generall be less reliable!). The CD250 would fall into the same category as the CG when it comes to tuning...
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Suzuki GSXR1000 K2
BMW R1150GS
BMW K1200RS
Chevy K5 Blazer
Chevy Suburban LT
Jaguar XKR
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Fungus
Part of things
Posts: 960
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Sept 27, 2009 10:24:28 GMT
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i think maybe i wouldnt tune it if thats the case. ive just had a look on ebay and cant find any cd250 engine. how easy are they to get hold of?
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slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
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CG125 engine conversion ideasslater
@slater
Club Retro Rides Member 78
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Sept 27, 2009 12:17:01 GMT
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BORING! use some inititive and build something interesting!
Engine swap fine, but its a bit pointless when you think about it. An engine could never be 'untunable'. Who cares if its got drums, tune them too. Otherwise just go buy a modern bike.
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Fungus
Part of things
Posts: 960
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Sept 27, 2009 12:44:10 GMT
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1.Its a pushrod 125 and ive already lapped the valves and polished the ports.
2.no.....i like old bikes;-)
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Sept 27, 2009 14:28:05 GMT
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what about all those Chinese bikes that use similar engines to the CG
some have bigger engines. so you could swap the engine.
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MrT
Posted a lot
Just who did Mr Hitler REALLY think he was kidding?
Posts: 1,773
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Sept 27, 2009 14:57:08 GMT
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what about all those Chinese bikes that use similar engines to the CG some have bigger engines. so you could swap the engine. The main problem with most Chinese bikes is that all the fixings appear to be made of a special low-grade marzipan... I might be wrong, but I'm sure the XL185 engine is a stretched CG125 engine, if that helps... |
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ant318
Part of things
Posts: 109
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Sept 27, 2009 17:30:56 GMT
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they used to do an xl185 would that gain you enough extra ooomph?
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Sept 28, 2009 15:27:33 GMT
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an xr200 might go in? obv not a pushrod but i think the bottoms end were in the same family
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Last Edit: Sept 28, 2009 15:29:18 GMT by TerraRoot
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ant318
Part of things
Posts: 109
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Sept 28, 2009 15:56:56 GMT
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an xr200 might go in? obv not a pushrod but I think the bottoms end were in the same family ooooooh forgot about the xr200 |
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Fungus
Part of things
Posts: 960
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Sept 28, 2009 16:34:00 GMT
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do you mean the top end or the whole engine?
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Fungus
Part of things
Posts: 960
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Sept 28, 2009 16:54:20 GMT
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Does anyone know if the xl185/xr200 barrels fit on the cg block?
what about the rods? I don't really know much about what difference the length of rods make, so if anyone could help that would be great:-)
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Last Edit: Sept 28, 2009 16:54:55 GMT by Fungus
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MrSpeedy
East Midlands
www.vintagediesels.co.uk
Posts: 4,786 
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Sept 28, 2009 17:25:36 GMT
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I heard that the CG125 is popular with the grass track guys because it is tuneable ! (mite be wrong tho  ) I think the XL is a progression from the CG. Got one here with a mashed gearbox. |
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Sept 28, 2009 17:55:42 GMT
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don't think barrel 's will go on, since the cg is pushrod the other chain.   this place has lifan engines that would do, check the pics if your bottomend mounting point are the same, i'd go for it. www.tboltusa.com/lifan.html |
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Fungus
Part of things
Posts: 960
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Sept 28, 2009 18:02:52 GMT
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Thanks alot for the research you did. really appreciate it!
a new enine might cost a bit more than i was hoping to spend.
if the xl185 is the same block, maybe i could use a xl crank, barrell and head. any thoughts?
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Sept 28, 2009 20:40:07 GMT
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