Backfiring

[tas]

hey is it normal for my 150cc atomik nitrous to Backfire? it dosent backfire when its idleling just when its rolling down a hill. my mate said its normal for a few backfires but it almost every 5 seconds. anyone know the answer to it or is it just normal?
Thcks

 

[mattbombers]

Is It back firing when you back off The throttle aswell? On my old pitpro 140 I had the same thing, re-adjusted the air/fuel screw and moved the e clip on the needle to the middle position, and cool gravy..
But, in saying that... Backfiring like that is generally caused by a vaccumme leak between the carby and the head so could be a torn gasket, loose manifold bolts or cracked manifold spacer or the likes.
Grab some wd40 , start the bike and let it warm up.. Let it idle and spray the wd around the manifold and see if it revs higher.. That will prove a leak.
Let us know how you go!

 

[tas]

yeah ill give it ago tomorrow cheers

 

[mattbombers]

No problem, one other thing check the exhaust header bolts are tight and check there is a flange gasket between the pipe and the head, also make sure the gasket is sealing the head to the pipe.. Another cause of backfiring so I believe

 

[tas]

that might be it becaue i noticed my exaust was loose the other day so i did it up but i havent taken it for a ride since