Backfire. How bad is it for the engine?

qfo · Post by **qfo** » Thu Jun 07, 2012 4:21 am

So i was wondering how bad are backfires for the engine? Are the pulses produced from the explosion outside the combustion chamber powerful enough to disturb the exhaust gases and burn an exhaust valve? Im asking this because i was making my bike backfire the other day by playing with the kill switch so i'd like to have your opinion on it. Thanks

masterdave · Post by **masterdave** » Thu Jun 07, 2012 4:32 am

as far as ive read elsewhere on here, yes if done very regularly it can cause damage to the exhaust valve, however if done occasionally there are no problems caused by it, i do it occasionally when riding past unsuspecting people i dont like, killswitch down for a few seconds, back off, nice fat flame outa the zorst, offending person made to jump lol. Also useful for deterring tailgaters!

tony.mon · Post by **tony.mon** » Thu Jun 07, 2012 5:39 pm

As above, +1, occasional use is fine, but don't overdo it.

The other thing that can happen is that if you induce airbox coughs too often you could unseat the carbs in the intake rubbers.

cupasoop · Post by **cupasoop** » Thu Jun 07, 2012 5:58 pm

Name dropping time.....

when I used to go out riding with Jim Moodie he taught me a wee backfire now and again was a good thing. It was like a free de-coke for your engine and exhaust. Also funny when you frighten folk as well.

qfo · Post by **qfo** » Fri Jun 08, 2012 3:53 am

Thanks for the replies. Are there any conditions that would be more likely to cause damage to the engine when backfiring?

masterdave · Post by **masterdave** » Fri Jun 08, 2012 6:07 am

Obviously the bigger the bang the more damage can be potentially caused, so maybe try and not hold the kill switch down for too long, also maybe try and avoid doing it repeatedly in a short space of time, will stop things from getting so hot!

scott02464 · Post by **scott02464** » Fri Jun 08, 2012 8:37 pm

Im going to do this tomorrow! Still a little boy at heart.... love making people jump ha

The wife hates me jumping out on her lol!!

Snoogle · Post by **Snoogle** » Sat Jun 09, 2012 11:34 am

Come on then...a step by step guide how to do a kill switch back fire?!?

Never done them before so dunno how to do it properly

lloydie · Post by **lloydie** » Sat Jun 09, 2012 12:10 pm

When riding .
Ride it up to 4500 rpm close throttle and turn off the kill switch .
Open the throttle and then close it .
When the revs drop to 3000 rpm turn back on the kill switch BANG :-) job done with a big ass flame out the exhausts

edds11 · Post by **edds11** » Sat Jun 09, 2012 12:12 pm

boys 'o' boys 'o' boys.......cant bleieve a lad from Lincoln doesn't know how to be a hooligan

Snoogle · Post by **Snoogle** » Sat Jun 09, 2012 1:24 pm

I can't believe somebody from sCUNThorpe is bad mouthing a Lincoln lad lol
I leave all the hooning about for the yocals...honest

Cheers for the tips

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