I took the baffles out of my V&H 2into2 Big radius. Gurgles and pops, sounds like a jake brake on a semi .... and i love it! Why would anyone want to make it stop?

 

I only know what worked for me. My 99 carbed EVO was popping in the exhaust and surging just a little at 50-55 in fifth gear. I removed the 42 pilot jet and installed a 45. I also replaced the 175 main jet with a 180. It ran way better and my mileage improved a couple of miles per gallon. I ended up with 50 mpg average. I have drag pipes and a K&N air cleaner, otherwise stock.

 

There have been many really well-informed posts in this thread, but I don't know if the average bike rider is in a good position to separate the good from the bad.

Under decel, one thing is always true: Very low compression, because the throttle valve shuts off too much air, compared to the rpm.

Go back to some old school basics, and three things are needed for an engine to start: Fuel, compression, and spark (properly timed).

So on decel, we've seriously reduced compression, not that other things haven't been messed with. As a result, not everything is ignited in the cylinder, and some unburned fuel-air mixture ends up in the exhaust. You can tweak the decel fuel mixture, excessively rich or lean, so it won't burn anywhere, and that will cure decel pop and backfire. But that's not anywhere near the same as claiming that decel pop is a symptom of a fuel-air mixture problem.

 

That is probably true Warp Factor. I changed jets in mine to cure the lean running and surging, and as a result it cured the popping also. I use to have to run the enrichner for a couple of miles till the motor warmed up enough to run with out it. Now I can use the enrichner to start it and then push it all the way in. By the way, that is what the manual calls for, keeping the enrichner pulled out for several miles. It just runs way better with bigger jets. My plugs would also be pure white although without any blistering. Pipes were snow white also. Now I have just a little color on the plugs and pipes are grey.

 

I remember when I was a kid I use to borrow my brothers 50 Chevy when he was working and pull the vacuum line off the carb for the windshield wipers. It would let just enough air in to give me a really nice pop on decel in second gear when coming to a stop sign. I thought it was really cool and got the girls attention. That was the important thing you know.

 

Yeah, I love the decel pop. But different strokes for different folks. I can tell you that I get asked about this several times everyday. Most riders seem to want to get rid of it.

The Thunder Torque Inserts were designed to increase low and mid range power without taking away from exhaust volume or from top end performance. Turns out they have a nice side benefit for some folks...they also change the AFR in the pipe so that it reduces or eliminates decel pop.


Good info...the one thing to add is that with decel enleanment, it is really hard to get rid of some popping when the injectors come back online around 1700 rpm.

 

How did you remove the baffles? It looks like they're pressed in pretty tight.

 

Took the bike back to the dealer and they removed and re-installed the pipes and clamps the correct way and got them sealed up on the headers , then re-dynoed again. After that it took care of 98% of all of the problem and now only gurgles some times at lower rpms and has the Jake brake sound the rest on decel's.

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When the wrench installed the mufflers the first time he didn't put the Clamps on correct,, actually about 1/2 of the clamp wasn't even on the mufflers and they didn't cover the 4 slots in the mufflers.

By doing that it caused the metal at the rear of the slots to actually rise up from and away from the headers when he tightened the clamps causing the air leaks.

SEE BELOW the pic of the slots.


They have to remove the mufflers and pound them out in the slot area to make them flat again so they would seal against the headers when they re-installed them again with the New clamps that was put on the correct way this time.

I'll add that this was the first set of Rush muffs that our dealer had ever put on, but still, that was poor workmanship on the wrench's part. He must have done some other poor jobs as he only lasted about 30 days before they fired him.


Here's a pic that show the 4 slots in the header end of the muffs, the clamps should go around and cover the slots, not just 1/2 of the clamp on the muffs like mine was done the first time.






sorry I didn't get back to Ya sooner, I haven't been on the puter for several days.

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Ahhhhh... The great debate....

WF is on point with his remark. There is a good article called "Burn Baby Burn" That explains decel popping. Similar to what WF stated.

Popping is ((usually, not always)) caused by a LEAN condition in the closed throttle positions of your AFR Table on fuel injected bikes. Enrich the fuel in the closed throttle positions in the RPM ranges that the popping occurs. You may also have to advance the timing in these ranges.

I usually start with an AFR of 13.3 in the affected areas and add fuel as necessary.