Hey MO! My scoot runs like crap! I can’t get the darn thing run much past 20mph! I’ve put all kinds of high performance parts on it, brought it to the mechanic, etc. What can I do! I keep it well maintained and have rebuild the carburetor and changed the oil. I’m stuck.
Well, you’ve indicated a couple of things that may be of help. Many people that ride scooter do so because the have to, often because they lost their license, or are just plain broke. I bring this up because they most likely are working on their own scooters, or are paying the local “mechanic” who works out of his own house, not that that is bad, there are many excellent backyard mechanics, I was one myself, but most of them just don’t know what they are doing when it comes to sccoters. 20+ years for motorcycle or car mechanic experience does not qualify you as a scooter mechanic, they are unique. So what happens is the many mistakes are made. One is that when the carb is “rebuilt” the slide diaphragm is torn or pinched when re-installed. You can see this if you have the airbox boot off and try revving the engine up and the carb slide does not rise up very far. Get it replaced and install it correctly.
Next, oil changes. It never ceases to amaze me how often I see the oil sumps of scooters overfilled. I pull the dipstick out and it is filled all the way to the top! This causes a partial hydro-lock and saps power considerably. It will also damage the rings by bending them. Even if you adjust the oil properly by using the dipstick the top end is ruined. Don’t do it!