Staintune Exhaust 'gurgles' on decel...

[jbs80106]

Mind you, this is a question about the exhaust on my BMW, not my GS650 but thought some on the board might have some feedback for me.

My K75S has a few aftermarket goodies installed, some of which I understand, some I don't completely. One is the exhaust. Sounds GREAT, but I notice when riding, and I let go of the throttle and engine brake, the exhaust pops and bubbles (reminds me of a perculator coffee pot or something). If I just release the throttle from 6-7k RPMs but engage the clutch, not gurgling.

From what I've been able to glean via googling, this may be normal (atleast seems to be normal for car applications). Fuel injection is new to me, but apparently this burping and such is attributed to unburned gas hitting the hot exhast and igniting.

Not really concerned about it, more curious......

It also has a Fox racing shock on it that I'm not too sure about either...but that's a different question for a separate thread....

Thanks!

[sharpy]

If it was carbs i just say air leaks on the exhaust side of things.

[dirtyfingers]

Mind you, I don't know too much about K75S's, wether or not its fuel injected. Regardless, most popping on decel can be fixed just by richening the idle mixture. Either done with mixture screws on a carb, or some type of fuel map tuner/programmer for fuel injection. If a richer mixture won't help, then perhaps there is an air leak in the exhaust system. This can come from a few places. At the exhaust port gaskets, or somewhwere else forward of the muffler. An air leak can also be caused by an emission control air injection system. I have had to resort to blocking off the air injection tubes in order to stop "popping".

[jbs80106]

Thanks....

the K75 is fuel inject (horizontal 3 cylinder at that) so just getting to know her. I believe there is an adjustment for the mixture and a jumper setting for high altitude (or not). I'm at 7,400 ft and its in the high altitude mode.

From what I've read, I don't think the popping is necessarily 'bad'. But because she was new to me with the aftermarket exhaust, I don't know if she did it with stock exhaust as well. The drama of learning a new bike....she's only my 2nd so......


Thanks!