My bike will only barely run with choke half on and it constantly backfires through exhaust and carbs, this problem came on gradually. I have cleaned the carbs in a sonic cleaner, replaced the air jets with adjustable ones, replaced main jets, pilot jets with various sizes, replaced plugs, air filter clean, carbs are sparking clean in and out. I prchased the bike new, and have given it the best of care, 16k on odometer, any suggestions will be greatly appreciated.
Re: How do I stop my bike from constant backfiring?
Its running lean. Could be a vent problem with the gas tank. try running with the gas lid slightly open.. if this doesn't work increase the jet size in the carbs.
Thanks skydiver, venting is one thing I haven't tried, have increased main & pilot sizes, no help.Thanks skydiver, venting is one thing I haven't tried, have increased main & pilot sizes, no help.
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If both cylinders are involved then it has to be a fuel delivery problem or a timing problem. If you have checked the timing (valve and ignition) then it's fuel and it applies to both cylinders (I'm assuming here). The tank valve may be gummed up. Flow may be restricted.
If it isn't both cylinders then it will likely be a carb problem on the bad side. Go through that carb again.
The popping or backfiring is caused by air leaks in the exhaust system and unburned fuel igniting. Try replacing the copper crush o-rings between the head pipe and the head. Seal the air leak and the popping should stop. You can have an exhaust leak start any time any where. Many times exhaust systems are replaced and the gaskets are not replaced causing the popping issues.
hi,sounds to me like the air fuel ratio is all up the ***,locate the air/fuel screw on the carb(normally on the side)screw the screw right in untill it stops,then back the screw out 1.5 turns,this should get the bike to run without the choke,once you have the bike running simply turn the screw in or out untill the bike settles into a nice steady idle,should be good to go,hope this helps...cheers
Ok, due to different terminology used by different people, I'm going to assume that by "backfire", you mean it pops through the exhaust system when you back off the throttle. On stock exhaust systems which use the "crossover" connector to connect the front and rear pipes, the backfire is usually caused by an air leak somewhere in the exhaust system.
When you back off on the throttle, the mixture is usually too rich to burn in the exhaust system. But, if you have an air leak allowing the scavenging effect of the system to **** air in, the mixture becomes combustable and is ignited by subsequent exhaust pulses.
Check your exhaust system gaskets and replace them if necessary. This should stop your problem. Rejetting the carb may be necessary as well.
I would take a close look at the valves, if you are sure the carb is entirely clean. (Accelerator pump and everything)
A closed up exhaust can harm an exhaust valve.
Start with a compression test.
Good spark?
Is the plug wet?
Yes, it could (and probably is) be an air leak. Check to be sure the carb is tight in the intake manifold, and make sure the hot-start isn't loose and is sealing properly. Also make sure all of the exhaust system joints are tight, an air leak in the exhaust will make a four-stroke pop and backfire like an old work truck with no muffler...
Yes, it could (and probably is) be an air leak. Check to be sure the carb is tight in the intake manifold, and make sure the hot-start isn't loose and is sealing properly. Also make sure all of the exhaust system joints are tight, an air leak in the exhaust will make a four-stroke pop and backfire like an old work truck with no muffler...
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