guys/gals,

i need your help. my nighster has v&h shortshots on it with quiet baffles, se heavy breather intake, and the fuelpak. ever since installing the pipes i have had decel popping. i figured it would go way with the fuelpa, but it didn't. i put in the quiet baffles, changed the fuelpak settings to match, and installed the intake. popping still exists. i talked to v&h and the only thing they suggested was chaning one of the settings, which i did, no change.

last night while on my way home from work, i noticed when the bike would decel pop/backfire there would be blue flames coming out of the pipes. what the hell is this? what is going on? how do i fix it? it the bike running lean or rich?

the bike runs great except for the decel popping?

thanks in advance

 

I can't tell you how to fix your problem but I will try to point you in the right direction. Decel popping is usually caused by the bike running lean. In your case, if you are seeing flames from the exhaust during decel, that has to be caused by unburned combustion chamber fuel burning in the exhaust pipe. It sounds like you are running rich or for whatever reason getting an incomplete burn in the cylinders.

 

If I remember correctly from my racing days, you're running too lean. An over-rich condition would produce orange flames and sluggish take-offs...

 

Thumper, I think you are right. I missed the "blue" flame whenI read the post.

 

just checked my plugs and they are white. looks to me like it is running lean.

any suggestions?

thanks

 

I'm of the opinion that the bike is too rich. Any flame during deceleration is spent, unburned gas in the exhaust being forced out by the back pressure created. When I was experimenting with different jets in the carb, the # 48 would pop and shoot out the exhaust when backing down. Sounded and looked cool but, it was hard to get started without flooding it and, mileage was brutal. If this is an injected bike, than perhaps he has other issues.If your plugs are clean, ??????????. I hate the fuel injection for this reason but, only for this reason. Damn computers.

 

hate to hear you're havin trouble,but i bet it looks cool at nite.

 

DITTO! Thank heavens mine's got a carb!

 

My bike was popping loudly on deceleration after the Shortshot pipes were installed. I have a Power Commnder soI increaed the gas at the closed throttle postion from 1750 rpm up to 6000 rpm and it quieted the popping about 90%.
There was a posting about this somehwere on here I can't remember where but it also suggested that if the pops were kind of a muffled sound then it was running too rich and to subtract gas at the 0% throttle position.
You have to have a fuel management device to do this of course.

 

If you didn't mess with the timing, then you have to retune it because the tuning is so off it's shooting flames out the exhaust.