noah9988
Well-Known Member
- Local time
- 7:30 AM
- Joined
- Jul 3, 2021
- Messages
- 468
My old engine (from a zeda 100 kit) blew the wrist pin clip, so I ordered a new YD100 from bgfmotors on ebay. Ported the cylinder as best I could, matched the gaskets and intake manifold, installed a 38t sprocket just to find out it has WAY lower compression. With my other engine you could hardly pedal the damn bike when you're trying to start it. The first time I tried starting it I was sure that I installed something wrong, and didn't even think the engine would start with that low of compression. I took the head off and did some tweaking.. it's a bit better now but it's still way under what my original was right out of the box. I never even took off the cylinder.
A few other things concerned be about the engine: the rod was marked AF80 (original marked YD100). The clutch cover has a damn hole in it. It has the pencil eraser looking clutch pads (original had white ones). There was a stiff spot when you turned over the crankshaft (rubbing bearing?). It makes a pretty loud rattle noise. It came with a 12mm wrist pin when my old one had 10mm.
Thoughts on this? The engine doesn't necessarily run bad, just seems like it's down on power because of the compression. I actually specifically bought from bgf because they accept returns... might prove to be a smart move.
A few other things concerned be about the engine: the rod was marked AF80 (original marked YD100). The clutch cover has a damn hole in it. It has the pencil eraser looking clutch pads (original had white ones). There was a stiff spot when you turned over the crankshaft (rubbing bearing?). It makes a pretty loud rattle noise. It came with a 12mm wrist pin when my old one had 10mm.
Thoughts on this? The engine doesn't necessarily run bad, just seems like it's down on power because of the compression. I actually specifically bought from bgf because they accept returns... might prove to be a smart move.