Hi, i'm still trying to determine why me scoot is running oddly... when its cold it runs perfectly, but as soon as it is hot it seams to pull away, then the revs drop for a few seconds :/ i'm pretty sure its not the roller weights, so i'm thinking it might be jetting. could somone tell me if it is correctly jetted by the colour of the spark plug, i've never done it before so i'm npot sure whats normal etc. anyway, heres the picture:
It's worth trying a new spark plug, since it's less then £5 for a new one. Then if the problem still persists reply back.
Just randomly taking out your spark plug and looking at it gives slim to no indication on jetting. A spark plug chop can give an indication if done properly but it's really not the best method. A proper plug chop to check full throttle jetting which is your main jet is done by fitting a brand new plug right next to a very straight road then riding at full throttle straight away then cutting the engine at full throttle coasting to a stop and removing the plug and taking a look. Of course this will only give an indication of full throttle jet and not any others. Read our carb guide for more information. http://www.scootershack.co.uk/carbguide.html
It turns out it was caused by the variator being worn, so the rollers tend to stick in the same place :/ i cant afford a new variator at the moment so i just greased it up with a shit load of vasaline - it works a dream now anyway does anyone know what % i should increase my jet when installing a 70cc kit? and thanks for the help guys
10% is a good starting figure, I tend to start high where it is struggling to run, then come down a size at a time until it is running well, then watch the plug for clues, if black, come down another size. Would rather settle for the mixture on the rich side, than on the lean. I normally adjust the clip one notch as well, that way more throttle positions are covered, as the main jet has most influence 3/4-full throttle, and on my daily work ride, I do a fair bit at low traffic speeds.
