I have a Yamaha Neos 50 and recently due to power problems I fitted a brand new cylinder, piston and clutch. I have done the required run in after fitting the new cylinder but have now gained a new problem. When I stop at a light or for any other reason the revs stay very high, by my estimate at least twice what they should be, then after a random amount of time anywhere from 10 seconds to longer than the light stays red the revs will drop back down to normal idle rev. Normally I would adjust the idle screw on the carb but since they do eventually drop on their own to normal this screw must be set ok. I have tried adjusting the air screw thinking that the new cylinder could be throwing the mixture out but this does not seem to help. At the same time is is now quite difficult to start when cold when before the change I could just pull the choke and touch the starter button and it would start right up. What else can I check to fix this?
same happend to me i just bought a new carb i wld say to look at jets in carb u might need to upjett it or give it a good clean make sure the throttle cable is ok or have a look at ur rollers and variator
Should have added the rollers are brand new as well and the variator was checked when they were replaced.
