Exhaust Popping

[Mike Ehrhardt]

New Poster here. Chicagoland area. I have a 99 RT1100. Valves adjusted, New Hall sensor. TB synched. New plugs. 69000 mi. Runs pretty well I think. It came with a Staintune muffler. Don't have stock one. A little louder than I would like, but I can deal with that. What I don't like is when I close throttle about 4000 rpm the ehaust makes a popping putt-putting noise. Best I can describe it. I wouldn't call it a backfire. More annoying than anything. Doesn't seem to affect performance, but how can I make this go away. Thinking maybe of buying used stock muffler and trying that. Don't know if any mods were done when P.O. put the Staintune on. Any suggestions.

[roger 04 rt]

Hi Mike and welcome to the forum. You'll find plenty of knowledgeable riders here who will help out.

 

Switching back to a stock muffler will probably fix your problem but before sending you down that route, let's try to figure out exactly what condition your bike is in.

 

Is an O2 sensor installed and connected?

 

Do you have any fueling mod on the bike? (E.g. Techlusion, PowerCommander, BoosterPlug, etc.)

 

Is there a catalytic converter?

 

Which coding plug is installed in the electrical box under the seat (left hand socket in the middle row). It should be yellow and have two pins on the bottom (30 and 87).

RB

Edited April 12, 2017 by roger 04 rt

[dirtrider]

New Poster here. Chicagoland area. I have a 99 RT1100. Valves adjusted, New Hall sensor. TB synched. New plugs. 69000 mi. Runs pretty well I think. It came with a Staintune muffler. Don't have stock one. A little louder than I would like, but I can deal with that. What I don't like is when I close throttle about 4000 rpm the ehaust makes a popping putt-putting noise. Best I can describe it. I wouldn't call it a backfire. More annoying than anything. Doesn't seem to affect performance, but how can I make this go away. Thinking maybe of buying used stock muffler and trying that. Don't know if any mods were done when P.O. put the Staintune on. Any suggestions.

 

Morning Mike

 

As Roger mentioned a stock muffler will probably stop MOST of the post-fire popping.

 

What happens with a lot of aftermarket mufflers is they are more open than the stock baffled muffler so allow reversion, that reversion allows the back-pulse in the exhaust at closed throttle to suck a little air (oxygen) back into the muffler & exhaust system. That oxygen then mixes with the remaining fuel in the exhaust & allows that partially burning mixture to light off so you get the popping & gurgling as you drop the throttle.

 

If your aftermarket exhaust doesn't have a catalytic converter the popping will be even worse as a cat is pretty good at stopping some of the reversion (my guess is you don't have a cat either)

 

 

That post fire popping won't hurt anything but sure is annoying to some riders.

 

Other things that can cause post fire popping is any air leaks INTO the exhaust at the joints as that allows air to be sucked into the exhaust at dropped or closed throttle.

 

Pretty well 3 ways to get rid of that post fire popping--

 

(1)-get an exhaust system on that bike that is baffled enough to prevent reversion,

 

(2)-set the fueling up to completely shut the fuel off at dropped throttle (BMW already sort of does this but not quickly or early enough),

 

(3)-run the fueling very/very rich at dropped throttle (basically make it too rich to fire off during reversion)-- some of the older Honda's used this approach.

 

 

[Rawed]

I had the same issue when I installed a Staintune on my '04 R1150RT. I had no popping with the OEM exhaust. The popping went away for the most part, once the bike was fully up to temperature. I eventually went back to the stock exhaust as I didn't like the noise, as cool as I thought it sounded when first installed it.

[SoCalBmr]

I once rode a rented H-D Street Glide that popped on decal so bad I quit letting it decel under load.

On my Honda750, I did a bit of mod on the muffler and it popped on decel, so I drilled a small hole in the edge of the muffler in the pipe and added a thumb screw cocked at an angle. That little bit of material provided enough back pressure to stop the popping. The bike is carbureted, tho.

[dirtrider]

I once rode a rented H-D Street Glide that popped on decal so bad I quit letting it decel under load.

On my Honda750, I did a bit of mod on the muffler and it popped on decel, so I drilled a small hole in the edge of the muffler in the pipe and added a thumb screw cocked at an angle. That little bit of material provided enough back pressure to stop the popping. The bike is carbureted, tho.

 

Afternoon SoCalBmr

 

Yes, adding a wing nut or bolt & tab, or bolt with eyelet can is some cases stop some of most of the post-fire popping.

 

But it isn't due to an increase in backpressure. --Think about it?-- You have already closed, or almost closed, the throttle plate(s) so very little air is entering the combustion chambers (little in=little out).

 

What little air that is entering is WAY less than riding down the road at part throttle. There is also very little combustion going on with a closed (or mostly closed) throttle so there is not a lot of volume exiting into the exhaust system.

 

Those wing nuts & other obstructions don't increase the backpressure they break up the reversion pulse (negative wave traveling back into the exhaust system). That negative wave is what carries the oxygen back into the muffler & promotes post fire popping.

 

In a lot of cases you can see that negative wave by holding a shop rag behind the muffler outlet then having someone play with the throttle then suddenly close it. You can actually see the shop rag getting pulled into the rear of the muffler or at least towards it.

 

[Mike Ehrhardt]

Thanks for all the input. This forum like several others is very helpful and informative. Not sure exactly what I will do yet. Leaning towards a stock used replacement. All I need is time and money. Once again thank you.

[joeb]

Ear plugs !

[Alan Sykes]

+ on the ear plugs comment !

My '04 Rockster has no stock 15kg-weight tin-box catalysator underneath, and has an almost straight-through 'Laser'-brand aftermarket end-can. So it pops and gurgles like crazy when i shut off approaching a roundabout. But think of the extra 5 to 8 bhp increase in overall power output and the loss of almost 20kg in weight - so regarding any popping, am I bovvered ? ?

[dirtrider]

+ on the ear plugs comment !

My '04 Rockster has no stock 15kg-weight tin-box catalysator underneath, and has an almost straight-through 'Laser'-brand aftermarket end-can. So it pops and gurgles like crazy when i shut off approaching a roundabout. But think of the extra 5 to 8 bhp increase in overall power output and the loss of almost 20kg in weight - so regarding any popping, am I bovvered ? ?

 

Morning Alan

 

 

Now that sounds more like hoping than factual measurement.

 

[Tri750]

Agreed. It's just noise.

 

When the R1200GS first came out, we, for a customer ordered a full system from Remus.

 

It claimed 6 HP increase when a Uni type air filter was used.

 

We sent the bike to our friends shop who had 20+ years with a dyno doing race engines.

We got a "before" reading, brought the bike back and installed the full Remus (no cat) and the air filter.

On the "after" run ,the thing met the advertised 6hp gain.

Too cool.

 

Remus is one of the few xhaust companies who actually have a dyno to engineer systems.

 

Back in '03 wh n I bought my Kaw ZRX I called Kerker/Supertrapp about a system for th bike and they finally told me they didn't own a dyno.

What ?

Anyway, slip one are pretty much weight saving and noise making items.

 

The worst over the years was 2 Brothers. They burned out quickly and the hardware was really budget quality.

 

YMMV