HUGE backfire issue!

[Nnn]

Backfiring is almost always from either a carb issue or the timing being off.

Clean out the carb jet first; if that doesn't help?, then try a new CDI (black box).

Also, make sure your gas & oil is properly mixed!!! (too much oil might also cause this problem)

Changed cdis still backfired. Carb is spotless and in terms of gas and oil all I do is fill up a water bottle then go 500 devided by 32 and i get 16ml of oil

 

[Tyler6357]

Checked the clutch and mag seals and everything is good no oil

If they were leaking you would see oil in there. Is the key at 1 o'clock? Also, the exhaust pipe is not clogged with oil is it?

 

[Venice Motor Bikes]

Try a new spark plug... NGK ~ B6HS gapped @ .025"

 

[Nnn]

Try a new spark plug... NGK ~ B6HS gapped @ .025"

Have tried 3 different plugs no change

 

[Nnn]

If they were leaking you would see oil in there. Is the key at 1 o'clock? Also, the exhaust pipe is not clogged with oil is it?

Key is at one o clock tomorrow I’ll check if the pipe is clogged

 

[Venice Motor Bikes]

Ok... Lets start at the beginning....

Was the engine ever running well?

Did you do ANYTHING to it just before the problem started, (such as clean the spark plug or adjust the carb)?

Was there any special circumstance that happened just before the problem started (such as riding through water or using a different gas or oil)???

Another thing you can check... Is there oil anywhere around the head gasket?? (leaking head gasket)?

 

[Nnn]

Problem solved. All it was is a loose nut for the magnet. As soon as I retightened it the engine was as good as new. It won’t idle now but that’s because the engine is acting like the mixture is too rich for some reason after I tightened down the nut. Fuel economy still sucks though

 

[Tyler6357]

Problem solved. All it was is a loose nut for the magnet. As soon as I retightened it the engine was as good as new. It won’t idle now but that’s because the engine is acting like the mixture is too rich for some reason after I tightened down the nut. Fuel economy still sucks though

Awesome that you figured it out, you could try some blue loctite on the screw so it don't vibrate loose again. Also, set your carb clip to the leanest setting, if it's still too rich, try a smaller jet.

 

[crassius]

Did you check that the woodruff key that controls the timing is still in there?

 

[Billsef Laurall]

the needle valve or float may not be working properly, clean that carb!