EXHAUST BLOWING & POPPING WHEN DE-ACCELETRTION!!

Noxymania · 06-22-2008, 5:57 AM

Hi, I have a Honda fireblade 900RRW and had it recently tuned. After travelling 1200 miles I have managed to get a popping noise when I turn the throttle off. I got the bike seen to and had the fuel adjusted on the throttle off which cured this issue last time. However, now I am getting popping noise from the exhaust when the throttle is released and AND a 'phut..phut' noise (not exactly like a backfire but a cross between a popping and blowing sound) when i increase the throttle. This new issue is sporadic every other second or so and gets more regular when the throttle is increased.. The performance of the bike is not affected though it does seem to stutter on idle and sounds resonating (likes a barbars quartet and 1 of them out of tune).

I have checked for air leaks on the exhaust through to the silencer, changed the HT Leads and Spark plugs and at a lost to what it can be?

kiai · 06-22-2008, 6:21 AM

lean maybe ? how was the plugs when you changed them?

Noxymania · 06-22-2008, 6:29 AM

well the usual dark brown colour not charcol. I had the bike tuned a month ago prior to the 1200mile journey and the bike seemed ok. They increased the amount of fuel on the "throttle off" to cure the popping noise on "throttle off" which did work last time. But as I say its now making a phut putt blowing noise on acceleration. Just thinking if it is one of the coils? or valves?

Its driving me crazy and the Haynes manual fault finding doesnt even mention anything about backfiring.. which is like but no a full back fire noise

speedtatctics · 06-24-2008, 11:46 AM

Are you running a stock or aftermarket pipe? The reason I ask is you pick up more of that with aftermarket pipes and it's normal. In fact you will still get some of that when you have a stock pipe as well. Keep in mind as you said. "the performance of the bike is not affected"

bighicks2980 · 06-24-2008, 12:08 PM

you might have got some bad gas, my girl zx-9 was doing the same at first we thought it was the plugs but it was just water in the gas so we just ran about a gallon of racing fuel and haven't had no problem at all

speedtatctics · 06-24-2008, 12:11 PM

It's just your gas burring off. Race gas burns cleaner and will not have the same problem so that would cure it. But once you go back to the old gas it will come back. Just my thoughts.

cbr900racer77 · 06-24-2008, 7:40 PM

any way you could get it to do that popping you speak of near your home? If so, get it to start popping then hit kill switch while clutching at same time and coast to your driveway. Then pull a plug and see what's going on. It has to be shut down while it's doing it or it won't work.