Ducar 124cc (125cc) engine rebuild

August 20, 2009 5:43 AM

I want to rebuild my 125cc dirt bike engine, never done it before but I want to learn.

I recently purchased a 2nd hand dirt bike and would like to rebuild the engine (something to do). I've never done this before, I'm good with cars though (pretty much everything except gearbox and bottom end). I need a workshop manual or something like that, looked everywhere but have been unable to find anything useful even youtube is useless.

This is the engine Ducar 124cc (China) designed in japan.

I've tried contacting the manufacturer and got no reply.

posted by jakubsnm to sports, hobbies, & recreation (2 answers total)

IIRC These are clones of Honda engines. There might not be any "workshop manual" for them, other than the one provided for the Honda 125.

(I don't know for sure)
posted by ArgentCorvid at 9:19 AM on August 20, 2009

My uncle & I did this with a Maico we found buried in the dirt back in '89. Then a Commando. Then a coupla C10s.
Looks like you've got to use your experience and reverse engineer the thing. Take plenty of pix along the way and catalog the parts as you tear it down. You should already know how to separate the major component parts (exhaust, carbs, etc.) Once you're down to engine block and heads, keep a good pen handy, sketch out idiosyncracies, even video what you're doing.
The design is likely Honda based (Honda was king in Asian engine design), so I'd suggest thumbing through a Honda manual and looking for similarities. If it's a hit (I'd put it in the 85%+ range of certitude), then there's your manual. Go Kawasaki second. After that, well maybe just spend an entire afternoon with a pile of books to find the closest one. There also might not be a lot of variation between the real dope you're looking for: torques, points settings, gaps. Pertty much everything else will be the same (but different from design to design). I mean, you're always going to have a piston, a pushrod, bushings, rings, and so on.
Last suggestion, make sure you know a good bike shop with their own machine shop, in case you need them to fabricate parts, or do some machining. Saves you 40% on the boring, planing, etc. And tipping leads to better advice.
posted by valentinepig at 9:47 AM on August 20, 2009