backfire

[samual]

hi guys , bike goes ok but when im in 4th gear it backfires sometimesor spits out,also on 1 ocasion im going along i loose power then she kicks in even stronger i cant work it out.

 

[pitbike125]

First thing to do would be to lean it out cus it sounds like excess fueli s leaking into the exhaust and causing backfire. If that dont work then u might have dirt in ure carby and u will need to clean it out. Let me know how it goes

 

[Matty]

i have just reset my valve clearances and they wernt perfect so mine misses and backfires aswel. but it may not be the same thing as yours.