I just put a K&N filter on my 150cc 4 stroke. What is the norm for jetting when you remove the stock air box 1 or 2 sizes bigger?

Also I have a 50cc kids quad with Zongshen 4 stroke. I want to check the timing and or adjust it. But cannot find a service manual for it and I got no reply from the manufacture or dealer. Its supposed to be a Honda designed engine like the old trail 50. It has CDI. Its really boggy at low RPM's. I put a 15mm Mikuni carb on it as the factory carb was a 19mm...and could not get it right.

Thanks

 

You will have to do a plug check to see where you are at as far as jetting is concerned.

As far as the aftermarket carb on the 50cc machine, My suggestion is to convert it back to stock, and stock carb settings. Keep trying the dealer and factory. Bug them long enough, and they will help you get it figured out (hopefully). [img]i/expressions/face-icon-small-wink.gif[/img]