Hello Everyone and thank you in advance for any advice you can provide. Also this is my first post. I have read some other posts regarding backfiring of this type of quad, but my issue adds another layer of complexity.
My quad which I purchased from a gentleman who couldn't figure this issue out thought he had it licked, as well as I did. He had replaced the carb with a brand new one and still had the same issue.
Here is the issue: Initially the quad ran great, didn't have any backfiring issues IF the ignition switch was turned all the way to the second click which is the lights on position. It would start and run fine. However, if the quad was run on the first ignition click - lights off, it would backfire and not run.
So the solution to the problem was simply to run the quad with the lights on.
Now, even if it is run with the lights on it backfires and sputters. It will not accept any throttle. It will backfire and surge if throttle is applied.
Thank you for any advice.