I have a yamaha bw, it go's very well on the flat, but very slow up hill. we have put new rollers,piston&rings
Answers:
Well bully for you! What's your question?
Have you checked the clutch / drive system ?
Check the fuel filter it might be clogged, or replace it. Check plugs also
The best thing for you to do is to get a malossi or polini variator. Then you can change the rollers accordingly. e.g if you put lower than 9.5 gram rollers you'll have better acceleration on the other hand 12.5 or above can give you better top end. I guess your bike is only a 50cc there for you dont have much power any way. Try getting a 70 cc bore kit. This is a bigger pistion and cylinder which means more power. much more!
Always give year, make, engine size and model # when asking questions. We don't know if it's a 50 or 80cc bike or scooter. Mileage will also be helpful answering your question.
A clogged muffler will give those symptoms.
A Yamaha what??
I had a bws myself (96 model) and it only reached 31 flat and 26 uphill, its just the bike really as all the reports i've read said they've got bad top end performance.
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