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Old 10-14-2009, 08:01 AM
Fabian Fabian is offline
Join Date: Sep 2009
Location: Australia - Melbourne
Posts: 168
Default Chinese Bicycle Motor - Bearing Part Numbers

G'day all

I am in the process of rebuilding my Chinese 2-stroke 69cc Bicycle Motor as the bottom end needle roller bearing connecting the crankshaft pin has failed.
Amazingly and even though the connecting rod can move in the vertical plane by 2mm (clunk, clunk, crikey that's a lot of play when moved about on the crank pin), the needle rollers are somehow still captive in the needle roller cage and give the appearance of looking ok.
I don't understand how this is possible as the motor was rattling it's guts out and the small end needle roller bearing looks to be in perfect condition.
Upon disassembly, a metalic mud film was found to be covering the crankcase area, so something in significant quantity has removed itself from the bottom end bearing and pin.

Now that the motor has been stripped down, i want to replace all the bearings and seals, including connecting rod needle roller bearings with high quality items.
Does anyone know a reputable manufacturer and a listing of part numbers and dimension specifications for replacement bearings.
When the crankshaft is rebuilt, i want to get it balanced with the new piston for a super smooth and reliable engine.

I'll post hi-res photos of the rebuild process.

Maybe Normans input might be of some help here

Cheers Fabian

Last edited by Fabian; 10-14-2009 at 08:30 AM.
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