yo! so my 2009 klx250s is backfiring when I drop off the throttle or engine brake. Is this just a result of the pipe? I installed an FMF Powercore 4 pipe and dynojet jet kit. It is on the third clip and I am about 2.5 turns out. The bike has the snorkel removed from the airbox. Should i drop to the second clip position and 2-2.5 turns out? I am at about 200o feet above sea level.

 

Make absolutely sure there are no exhaust leaks both at the head and at the join.

 

ben, search the forums for this. I have this issue when i pull the baffle out of the 300 exhaust i have sometimes. My understanding is that it is actually from a lean operating condition. I dont remember the reasoning and it seems counterintuitive, but i found a few sources that gave the same reasoning, and it seems to make sense being that i dont have the issue when i have the baffle in with some spacing washers. Does it typically happen going from high RPM and forcing the throttle closed?

 

need to go up on the pilot jet.

 

try closing off the secondary air system. this allows air into the exhaust to help reduce emissions.the valve is located in the cylinder head just above where the exhaust pipe joins the head.

 

However you decide to block this off, make sure it's tight and the gaskets are seated properly. I had decel backfiring after removing this system and didn't put the gasket on the blank off plate. The backfiring ceased immediately after I rectified this problem. That's why I also mentioned the exhaust system. Make sure it's sealed well. Good luck, you'll get it.

 

I fitted a two bros slip on and got alot of decel popping. Got some great advice from the forum.
Search the thread "Added new exhaust" by Winter737. Some good advice from Army Copter, Ramjet & Candyass.

Hope this helps.

 

Do you have a part number for that blanking plate.

 

Here is the thread: https://www.kawasakiforums.com/forum...=Added+exhaust