the simplest thing you could possibly do with no mechanical experience ever to make your bike stop backfiring ,( disclaimer ) do this at your own risk , im not responsible for your bike sounding better only you are :)
PAIR feeds excess throttle body fuel/air back into the hot exhaust causing it to combust instead of going out into the air. Part of why the stock bike gets so hot. The header and pipe are cooking off the waist fuel/air from the throttle body causing backfire. What a dumb regulation shortcut by Kawi.
It's not technically backfiring, it's a post engine combustion of unburned fuel. It happens with the stock exhaust too, you just don't hear it. But I also deleted mine because I hate the sound. I have an aftermarket carburetor (2012 KLX250S) so the pair valve wasn't connected to the vacuum port anyway (but it still did it), so I removed the whole thing and just put caps on the engine inlet and the airbox. There is nothing in the engine other than a reed valve, but it needs to be blocked or it will suck in air, and the air box needs to be capped or unfiltered air will get to the engine.
Ahhh thanks have the same bike with the same exhaust with same tuner (judging by your sticker) thought this might be a tuning issue now to find the plugs u used
Isn't it just lean? Shouldn't you adjust the fuel map in the ECU so it doesn't run hot and backfire? I only ask because I have the same problem with my pipes glowing red hot, so I know it's a fuel map issue...
It's just the way the bikes are designed. In order to meet EPA regulations they have to bur any excess fuel in the pipe to keep it from exiting the tail pipe.
It's designed to pull air from the airbox into the header pipe to bur any excess fuel. It's one of the reason the header is pro to turning red. The deletion of the pair valve reduces air in the header pipe and helps reduce heat in that area.
@@killerX9979 Mine came from eBay. Not strictly a 'legal' item in some instances. "KLX pair valve block off". You'll also need a module from smart moto to keep the CEL off. Good luck
@@Synthsnstuff84 Well, I have been riding for over 50 years. Fuel loading is a bit different than backfire. I wasn't trying to be nasty. Good that you fixed it though.
Technically, a backfire is when it backfires through the intake valves and carb. A backfire is really bad and has been misused for fuel loading since the 70's. Fuel loading is when the fuel is not fully burned in the combustion chamber and is ignited after the exhaust value by hot components like a header or collected in a muffler and when it gets to a critical amount and fires. There are other types of issues like ignition timing, valve timing or the way the intake butterfly closes when the throttle is released and the fuel ratio changes and creates either a fuel load issue or lean fire issue. All of the latter 3 issues will pop out the exhaust pipe. When I built cars in the 70's you would often see a backfire with flames coming out of the carb.
@@RedboneUnincorporated did you have issues with your header pipe turning cherry red? I'm not ready to spend the $400 on an ECU but I need to do something because the header on my bike is constantly turning red whenever I'm riding slow on technical trails.
@romand123 Yes, these bikes come lean, which will make a red header pipe, and it will wear out your engine quicker. I don't know of another solution than to break down and spend the money on an ECU. Sorry!
@@RedboneUnincorporated thanks. I just did the pair valve delete and tested and it seems to be keeping the header pipe cooler and not turning cherry red, even with some slower speed trail riding 🤞
