Im having problem with thing, My 6 year old thinks it funny but i dont. When he has full throutle and lets up it backfires. Anybody have any solutions for this. Brand new.

Have you moded the motor any? It could be lean,or have a leak in the exhaust manifold.

Jeff

I agree that it sounds lean. I would try going up on the main jet. I think stock is an 80, so a 90 or 100 might clear it up.

this thing is brand new i didnt do no mods, its fast anof as it is but the back fire is there. It is cold here.

The cold air well change the air to fuel mix so you might have to adjust the carb to get it richer.

Jeff

do i adjust clockwise or counter and how do i no how much or do i take it back to dealer. I was hoping it would be something simple but i dont want to void warenty. Is the backfire a real problem that will damage the engine.

Here is a link to the Dazon 90cc service manual I uploaded to the Service manual froum this should have everything you well need.
http://www.buggynews.com/topic6785.html

Jeff

ok been running all summer and the machine is getting harder and harder to start. I have to drift start and run around yard and it seems ok but it still backfire. I have tried cleaning carb and tried without filter and hard to start. Changed spark plug still hard. I tried adjusting carb and didnt help.

If your plug is new and the gap is correct (always check the Gap) and if all correction to the Carb have been made correctly there may be a slight chance the fuel you are using is causing the problem. It's unlikely but possible, Many of these engines need 92 octane or better, and if you keep changing the fuel type if may cause a problem.

back fire gone, I did 3 things first made sparkplug gap perfect(opened little) and then took exhaust off and cleaned took strange washer out. Then I took spacer out of the throttle. and now no back fire. YAYAYA!!!!! It is still very hard to get started. I dont know what the fix was. This thing really goes fast with out spacer in throttle. I mean fast!!! My son loves it.