bike backfiring

[vulcan03]

I just installed Vance and hines pipes, power commander III usb, Chuckster single plate , download the valid map. All the reeds valve and plugged up, the cross over tube removed. For some reason when I give throttle fast when riding or in neutral at times she backfires pretty loud.

03 1500VN L4 Nomad...

any idea what to look for or advice ?

[ringadingh]

Its probably an exhaust leak at the flange, make sure its snugged up nice, if that doesn't help you may have to remove and replace the pipe getting it to seal better.

[AlabamaNomadRider]

Does sound like a leak at the exhaust. Might want to loosen and make sure it is snug as Ring mentioned and retighten. Might want to add a washers under the nuts also if you don't already have them.

[vulcan03]

The slip on are HD ones,, but the headers are Cobra... I think I might a leak at the joint.. was told to apply a sealer called permatex ..that orange stuff then clamp both piece to together and let it cure for 24hrs. I did put my hand around the ring and did not feel any air coming out.. The backfiring seem to come from below.. will update

[upside22]

Check your plugs and see if they show you running rich at all. Backfiring out the muffler is many times an indication of unburned fuel collecting in the exhaust. If your processor is dumping too much fuel into the system when you crank the throttle open that could cause what you are hearing. You might need a different map in your power commander.

[vulcan03]

That is truly possible.. I downloaded the one that they have on their site. Now not sure what to do as putting in a diffrent map.

I have a 1500 nomad 03, vance and Hines pipes, Chuckster single plate intake.

So far I have map M202-006 and wonder if a different map should loaded....

[upside22]

Try the 001 or 002 loads and see if it fixes the backfiring. If it does you may need to talk to the power commander people. If it doesn't fix it then you have eliminated one possibility.

[vulcan03]

Earlier this winter I had installed a pair of tapered Cobra, I put them on the bike was working fine with the proper map but they were not loud enough. I took them off the biker and installed a pair Hance and Vines HD slip on over the header pipe form the Cobra ones and right away they would backfire a lot when I gave throttle from 1500 to 4000 while at idle and again would backfire on the test ride as well. I notice the plugs were pretty black telling me that it runs possibly too rich. as you suggested uploaded ,map 001 which is the stock set up and the backfire was some what less but still there. IF I live run idle it runs good and does not stall....

[vulcan03]

Well put the Cobra pipes back on only to find out that the Model of Vance and Hines pipes don't give the engine enough back pressure and the bike will never run good. Now will go this Friday to have my mapping looked into .. to make it run smooth

[mikeyger]

Add torque cones to add the lossed back pressureI did this as vulcan e suggested when i went with ultimate baffles and does does make a difference!