Can the exhaust popping be partially or fully remedied?

maverickma · 05-09-2015, 01:37 PM

Before I start looking for an exhaust leak or before I buy something to richen the fueling, I'm curious what changes you guys have made that have helped remedy (partially or fully) the exhaust popping on deceleration. I have a 2002 R1100S BCP which is completely stock and I run high octane fuel, the recommended sparkplugs, and the air cleaner and battery is brand new. She's also had her complete 12k mile service.

As stated, I get some popping in the exhaust on closed throttle...not all the time...more often when the engine is hotter (slow moving through town or just restarted after refueling), again only closed throttle on deceleration and at slower speeds below 30mph. Understanding it's a characteristic of the oilhead, I'd still like to lessen it a bit. Please help a boxer noob out.

Mitch1100 · Mitch1100's Garage

I like it

Nitro · Nitro's Garage

At close throttle the mixture is too lean. With a carburetor, the fix is to swap a bigger pilot jet.

With a Powercommander, you just put bigger values on the 0 throttle column. I still had some popping when I first installed the PC, I just filled the first column with lots of 20s and all the popping went away.

RIQUE · RIQUE's Garage

Since I removed the Cat on my 1200 and installed full Ti pipes I get it now and then and I love it. Sounds like those Moto GP bikes entering the curves....vrooom, pop, pop, pop...vrooom!!!

Jozef Schumann · Jozef Schumann's Garage

a simple TPS adjustment.

maverickma · 03:35 PM

Forgot to thank you guys for the responses. Thanks! Will take all into consideration.

I wanted to point out that I did find a small exhaust leak at the clamp that connects the left and right exhaust manifolds. It's sits under the front of the bike and it's a clamp on the crossover pipe. Can't figure out how to address that leak since everything appears to be mating properly. Wonder if that might be the cause of my popping.

Paulaner · 05-23-2015, 02:38 PM

I have that same leak, the clamp actually has a groove that looks like it is intentional to let a little air out?
I've tried a few ways to mount the clamp, but no matter what I can feel the exhaust pulses when I put my hand down there. I was worried about it a few years ago, now I just enjoy the pops.

maverickma · 05-23-2015, 06:17 PM

Hi Len, yeah it almost appears that it is intentional...it's strange.

wswartzwel · 05-23-2015, 06:56 PM

Water drain.

They all pop on decel. Part of the bikes charm.

Cruzer · Cruzer's Garage

Performed a "catarectomy" couple of weeks back. Left the OEM cans in place.Just love the sonic improvement and multiple resonance points throughout the rev range. Actually sounds like a sport bike now.
Reminds me of that Austin-Healey 3000 head turning roar. Nice!

Question is this:

No popping, idles perfectly @1100... lovely and responsive..there's a "chuffing" sound that I don't remember, when backing off the throttle. Now maybe it's something that I just noticed as the newness wore off. Checked for exhaust leaks and did the "dollar bill" test for burned valves. All good.

Any ideas?

maverickma · 05-26-2015, 06:48 AM

Cruzer...I'm curious...did it pop with the cat on? And what is the dollar bill test? Is that when we go to a BMW dealer and they drain your bank account?

Cruzer · Cruzer's Garage

Maverickma... Popping stopped as a definite "backfire", when I put in the BoosterPlug sometime back. If I remember correctly. Made a few minor improvements as I learned how to tune it for smooth. Collectively they added up to more than the sum of the parts.
The cat had been overheated and was just a big screen which had bad breath.
The $ bill test is putting a dollar bill over the exhaust when running. If it gets sucked back, then an exhaust valve is burned. Simple. Didn't do a compression test but it does run very well. Next time I'm at my brothers we'll dig out the tester just in case.
Yah... I'm with you on the "stealer."

maverickma · 05-26-2015, 08:01 AM

Ah so fattening up the fueling with the BP helped with the popping. Ok cool. Interesting about the dollar bill thing...had no idea.

Cruzer · Cruzer's Garage

Google search is a wonderful thing.
I met Dean from SJBMW in Cruso, NC.. a very interesting man and asked him about the fueling on the R11S. I had put his K&N PowerFlow fliter as well as the Fiberglass PowerDuct. Not near as pretty as Lennie's giant angular CF didgeridoo but at least as effective. He told me that in his opinion, the Motronic would make all the necessary adjustments. I already had the BP in place. Motronic takes a few cycles to even things out but the improvement was instantaneous. Went with the BP cause it's plug and play. Thing is where to mount the air temp sensor. I mounted it under the steering head on the wiring, when I had the tank off. Cheap. It works really well in my experience. Many threads about it here. Don't mean to flog a dead horse. There are other options and I.. like you have come late to the game...we reap the benefit of serious pioneering efforts.