First off let me say hello to all and I'm sorry that my first post here is jumping right in with problems. I have a 2004 Neos 50 and I am having wierd power issues that I am having trouble pinning down. Sorry for the strange post layout but I have posted this in more than one place and rather than retype everything I'm copy pasting. Original fault: Off the line it accelerates fine, at about 17 kph you can hear the engine note change and feel the pull as it picks up speed. At about 35 kph it seems to lose power and creeps up to about 45 kph and does not seem to have any pull to go faster. If there is a slight incline or a tail wind to assist it and it reaches around 55 kph then you can litteraly feel the power return and it accellerates all the way up to 70 kph fine. The only way I can describe it is a mid range loss of power. Now if I remove the little rubber pipe from the top of the air box (the air intake pipe not the thicker one connecting the air box to the carb) and put the choke practicaly full on then it seems to accellerate all the way through to 70 kph fine. Unfortunataly I can't run it this way as it is way too loud and with the choke full on it uses way too much fuel. When we bought the bike it had lighter rollers in it, had the bypass pipe removed from the exhaust and had the restriction washer removed from the variator. I have checked the air filter put a brand new set of rollers in and replaced the spark plug. I really am at a loss to figure this one out Troubleshooting: I have done some testing to try and pin it down. A compression test gave a reading of 65 psi but I do not know if that is good or bad. I did discover that when I replaced the plug I did not use a resistive one like was originaly fitted, when I corrected that it evened out the acceleration but it's still lacks top end power. When cold it accelerates perfect right through it's range up to around 70 kph Does anyone here have any ideas?
To me it sounds like both the size of the jet and the roller weight may be wrong. Try reading these and seeing if they help... http://www.scootershack.co.uk/rollerguide.html http://www.scootershack.co.uk/carbguide.html
The scooter ran fine up until a week ago. Rollers were replaced yesterday with same wieght ones that it had been running fine on up until now
Oh and 65psi is very low. Should be much higher than that so i'd be taking the head off and having a look. Could be something as simple as just needing new rings or could be totally broken.
Well I have fitted new rings and it has made no difference. Ther was a bit of minor scoring on the piston and the barrel so it looks like a full top end rebuild is next ---edit--- I have just ordered a barrel and piston replacement kit (barrel, piston, wrist pin and all gaskets) and a new clutch. Once those are installed that means it has had a full top end rebuild new rollers, new plug and a new clutch so hopefully that sorts it out. if not it will have to be either the carb or electrical.
