Bad Decel Popping

[narow37]

Bad Decel Popping with pics

hey guys,

wanted to run this by everyone before i took the pipes back off. I am getting a lot of decel popping. i adjusted the idle mixture and idle and changed the inter. jet to a 31. i went to friend that owns a auto service shop and he rides as well. he measured the exhaust temps at the head and the front was at 125ish and the rear was at 200ish. this should mean that the rear cylinder is running lean. my question is, could this be caused by a bad seal on the exhaust gasket and if not does anyone have any ideas. thanks as always

shane

 

[P8RIOT]

Sorry I can't give you any technical detail, but I can offer a little encouragement. My Big Radius pipes have been on for about 3000 miles now, and they almost NEVER pop - so I know it is possible to get them dialed in. Another friend with a K-9 just had his retuned by our local dealer, and they eliminated all the popping for him as well. Hang in there - I'm sure the techies on the forum will have more detail.

 

[narow37]

oh i know it can be fixed p8riot. i put my dads pipes on with the exact same setup and he has no problems at all except a little decel hissing.

 

[narow37]

Took some pics of the spark plugs for you. they look just like they should to me, but please give opinions. right now I have just over 4700 miles on her.

front cylinder

rear cylinder

 

[Gas Man]

Nah...that is lean! They should be a nice cinnamon brown.

 

[Gas Man]

Go to a 32 int and turn down the accel pump. I had to do this earlier in the summer.

 

[woodbutcher]

gas, would altitude make any difference? under 50 ft. above sea level.

 

[FatDog]

If anything I would have to agree with GM, they look a little on the lean side.

 

[woodbutcher]

If anything I would have to agree with GM, they look a little on the lean side.

no doubt about gas' knowledge, just giving more info for an easier diagnosis.

thanks gas:up:

 

[kickstart]

Look here

http://www.nightrider.com/biketech/tips_air_leaks.htm

http://www.nightrider.com/biketech/spkplghnbook.htm#tips

 

[Gas Man]

check for an intake leak first.

I thought he did that... but maybe that was a different guy.

To do so... with the engine running, spray the area where the intake and the heads meet up with brake clean. If the idle rises... intake leak.

 

[narow37]

just tried it with Brakleen and got no result. sprayed it on the heads and on the manifold to carb gasket. i tweaked the idle mixture a little richer and that did seam to help some. any other ideas. thanks

shane

 

[Gas Man]

I got back to my original suggestion.

Under stand that more than half of your riding is done on the int jet. And as we said.. it looks a bit lean. Remember, the gas itself cools the combusion chamber.

 

[narow37]

i opened up the idle mixture a little more and that got rid of about 90% of the backfiring. now i just have the decel puffing which i think is completely normal.

shane

 

[Gas Man]

decel puffing?

 

[narow37]

decel puffing?

You know, instead of loud backfire popping its just low noise "puffing" like air moving.

 

[Gas Man]

That would be the stock BR sound. Can limit it by cutting down the stock baffles or eliminate it with big city thunder baffles

 

[Sparks]

Torque cones can help too, anti reversion cones is what some call em.

 

[Chopper Dave]

narrow....if you want ....go in the gallery and scroll down to member video's...I have a couple of short clips of my bike running with my B/R baffels cut down to around 4 and 3/4 inches. I still get some decel pop....but I like the sound alot better...it sounds better in person...I used a digital camera with a little small ass mic...its sounds ok on here...next time ...I will use my buddies digital camcorder