Rae Posted February 7, 2022 Report Share Posted February 7, 2022 Hello all, ive got a new to me 2018 Montesa 4rt with a backfiring problem. it tends to only backfire (or after fire) when I’m holding revs at a higher rpm than idle. It tends to continuously foul plugs as well. I’ve gone through 3 plugs so far and after every warm up, it’ll foul a plug. The plug also slightly smells of gas. It starts 2nd kick when cold, but starts 1st kick when warm. things I’ve checked so far: 1. Cleaned air filter and removed excess oil 2. new spark plug (cr 6) 3. Valve clearances set per manual 4. resealed and tightened exhaust connections 5. new fuel (93 octane non ethanol) Other things I’ve thought but haven’t tried: new coil different gas with 10% ethanol hotter plug (it’s 30 degrees f recently) could anyone guide me in the right direction? Not sure if the idling sounds right either… Quote Link to comment Share on other sites More sharing options...
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.