Baron's and a whole lot of popping on decel

[george_park]

Hello all,

 

I just installed a set of Baron's bag slash pipes (and ah yeah, they are loud...) and plugged the AIS.

 

I removed the front and rear AIS hoses and used a 3/4" and (3) 11/16" plugs to stopper up the mechanical parts as well as the hoses and yet I'm still getting a heck of a lot of popping on decel. I don't think it's any better than it was before I put the plugs in and I know no air can get by those plugs - they are shoved in there tight.

 

One of the guys in our ride group has the same mufflers and had to rejet and I know just about everyone has had to say you don't have to but maybe there is just something different on the '06 and later bikes that needs to be specially tweaked?

 

Any help appreciated,

gp

[mashley]

I installed a set of these as well on my '08 RSTD, I'm having the same problem.

[RSTDRIDER]

I have them on my 07 and have the same thing. even synchronized the carbs and plugged the ais. The head wrench at the stealership checked the system for air leaks and all was good. He also said he didn't think it would cause any problems as it's not backfireing. I've had them on for a year and put about 20k on them with no adverse affects. And, yea they do sound good!

[Venturous Randy]

Popping on decel is a typical exhaust leak pulling in oxygen under vacuum and firing. I bet you guys have a leak somewhere.

RandyA

Edited September 24, 2008 by Venturous Randy

[Neil86]

Randy is right...if the popping started with the muffler installation probably the gaskets are bad....do the Barons come with gaskets or did you reuse the ones in the old mufflers?

Another spot to check is Yamaha had some exhaust cracking issues on the 2nd gens...I believe it was where the back cylinder y's into the system...look for discoloration on the chrome around the joint on both sides of the bike.

[V7Goose]

The afterfire is caused by excess fuel in the exhaust system that combines with fresh air and burns - do a search for old posts by me for a lot more detail I won't go into here.

 

The AIS, provided it is working correctly, will NEVER cause an afterfire - in fact, it is specifically designed to PREVENT popping on decel. So, while plugging the AIS helps on some bikes, it in fact only MASKS the real problem, never fixing it.

 

Most likely your real problem is vacuum leaks from bad caps on the intake nipples - if you have a problem here, NOTHING is going to stop popping on deceleration (at least not anything you are remotely likely to try). You may also have leaks at the Y joints in the headers (common Yamahaha problem), leaks where the new mufflers mount if you did not use proper gaskets, or those pipes might simply be too "open" to the atmosphere, kinda like straight pipes are. It is unlikely that enough fresh air can get sucked in from the end of the muffler, but possible. I'd focus on the Y joint or muffler gasket.

 

Bottom line is that the afterfire is caused by two things together - too many unburned hydrocarbons in the exhaust (running too lean, bad plugs, etc. etc.) AND fresh air to supply the oxygen needed for it to spontaneously combust in the pipe. Fixing either will solve the problem, but you really should fix both.

Goose

[george_park]

Hmmm,

 

The Baron's are slip on muffs so nothing else in the exhaust has been modified.

 

The slip ons have no gaskets - just a clamp that tightens the muffler around the exhaust pipe. I'll try and tighten that up a bit.

 

Other than plugging the AIS - and totally blocking up the tubes in the process - I literally touched nothing so I'm down to just a few options unless I'm missing something.

 

Regards,

gp

[eazyduzzit]

I just bought an '05 RSTD with Bub's and it does the same thing. I test drove 2 others before I bought this one. One had Bub's and the other had stock exhaust. They both popped on decel. The one with stock exhaust was quieter, but you could hear it. I don't know what it is but it seems pretty common.

[george_park]

I'm going to use some permatex where the slip-ons meet the exhaust pipes to see if that helps.

 

My stock pipes never really "popped" like these or the HK muffs I had on recently - with the new pipes (Barons) it sounds like someone is shooting a shotgun.

 

On my VStar nothing I did would stop the popping until I had it rejetted, something I did not want to do on my RS but may end up doing like a few other people I ride with had to do.

 

Regards,

gp

[V7Goose]

For those of you who continue to have popping on decel, please re-read my post. If you have caps on your vacuum ports from Yamahaha over two years old, you DO, ABSOLUTELY DO, have at least two vacuum leaks! Trust me on this. I have taken the caps off and shown them to owners who have sworn to me they were certain that the caps were perfect. And to compound the problem, even if they aren't cracked, the rubber gets kinda hard and will leak around the nipple.

 

And if you still have the vacuum lines on two of the ports, I believe you have about a 50% chance of having at least one of them with a small hole cut in the rubber near the end of the nipple from someone trying to pull them off with pliers. You can't see those holes unless you pull off the line and bend it. Start with the easy stuff!

Goose

[george_park]

Goose,

 

Do you have a recommendation for a replacement [part] for the caps?

 

Would it be possible to post some pictures of where they are (or note the post, tell me exactly where the caps are and I'll see if I can take them)?

 

On the Barons pipes there are 4 slots at the end of the muffler and a "hose clamp" muffler clamp. I don't think I could get enough torque to collapse that pipe unless I used an impact wrench, I've added just enough seal to see if that helps the problem, then re-tightened the clamp.

 

If not I'm taking her apart again!

 

Regards,

gp

[V7Goose]

Goose,

 

Do you have a recommendation for a replacement [part] for the caps?

 

Would it be possible to post some pictures of where they are (or note the post, tell me exactly where the caps are and I'll see if I can take them)?

 

On the Barons pipes there are 4 slots at the end of the muffler and a "hose clamp" muffler clamp. I don't think I could get enough torque to collapse that pipe unless I used an impact wrench, I've added just enough seal to see if that helps the problem, then re-tightened the clamp.

 

If not I'm taking her apart again!

 

Regards,

gp

 

Sorry, I don't have any picture available right now. Look at the intake manifolds between the front and back carbs on both sides. Each manifold has a brass nipple - one is capped with a rubber cover, the other one on each side has a vacuum hose going to the AIS valve to cause it to close during high vacuum (when the throttle is closed).

 

The stock rubber caps are very large and thick, but do not let this fool you into thinking that they must be high quality and robust; in my experience, they WILL leak in two years max. I actually replaced one of mine with a stock cap just 14 months ago and it started popping this week! I simply reached down and pulled it out slightly to cause the ridge on the nipple to push on a tighter part of the cap and it stopped, but that will only last about a month or two. I don't recommend buying new caps from Yamahaha because they are so poor. Instead, just pull one off and go to any auto parts store and find new caps to fit the same size port. These will be MUCH smaller/thinner than the Yamahaha part, so you will also need to pick up new spring clips, but even then it will cost you less than buying them from the dealer.

 

You said you plugged the AIS, but your reply makes me wonder what you did with the two vacuum hoses? If they are no longer being used, you need to cap those ports also. Finally, if any air at all is getting into the AIS lines running to each exhaust port, you will NEVER stop the popping - that is why the AIS valve is designed to make sure those lines are closed during the times when unburned hydrocarbons are typically high in the exhaust system.

 

I don't want to preach, but I have to add this at least once - injecting fresh air into the hot exhaust is an important and extremely simple way to dramatically reduce the smog producing exhaust emissions, and these bikes will run perfectly without any popping if they are set up correctly. By properly fixing the problem, not only will all of our air be cleaner, but the bike will run better too! Here is a cut/paste from an older thread where I already shared some of the details:

 

 

Inducting air into the exhaust system is to cause the unburned hydrocarbons (gas) to burn before they are blown out of the tail pipe. Just for further explanation, the only difference between a car's air injection system and our air induction system is a smog pump. Our system is passive, with the air just being sucked into the header pipe from the exhaust gasses rushing by the induction ports.

1. Hydrocarbons: this class is made up of unburned or partially burned fuel, and is a major contributor to urban smog, as well as being toxic. They can cause liver damage and even cancer.
   
2. The AIS reduces the products of incomplete combustion (hydrocarbons and carbon monoxide) by inducting fresh air into the exhaust manifolds of the engine. In the presence of this oxygen-laden air, further combustion occurs in the manifold and exhaust pipe.
   

The popping we hear is an afterfire, not a backfire (backfire is an explosion through the intake tract or carburetor). The purpose of the AIS valve is to STOP the afterfire caused by the oxygen inducted into the exhaust manifold when the accumulation of unburned gas is too great. When the intake vacuum suddenly increases from snapping the throttle shut, that causes the valve to close, stopping the air from being inducted into the exhaust system, and STOPPING an afterfire at that time.

 

So now the question is why the unburned gas in the exhaust is sometimes so high that we get an afterfire while the AIS valve is in the normally open position? This is caused by incomplete combustion of all the gas sucked into the cylinder. The incomplete combustion can be from multiple causes, including too lean condition (caused by that intake vacuum leak I keep yelling about), fouled plugs, unbalanced carburetors, or faulty ignition system. ALL of those things are bad, and that is why I keep saying that it is more important to fix the real cause of the afterfire than to just hide it by stopping the air induction.

 

I hope that explanation helps.

Goose

 

Oh, one more thought for gp - those four slots in the front of a muffler are more than enough to cause the popping; they are actually are bigger than the common leak in the stock Y pipe that is just a couple of inches forward in the exhaust. Fixing vacuum leaks will reduce the popping, but fixing both vacuum and exhaust leaks will be necessary to eliminate it.

[george_park]

Wow, thanks for all the info.

 

I'll take a look at my caps, plan on installing new ones.

 

I put Permatex on the pipe and the muffler before installing them and clamping them.

 

I used some blue painters tape to keep the permatex off the chrome but fill in the holes.

 

I'll let that cure today and will give it a run, take care of the AIS and caps while it's raining this weekend here in PA.

 

I also spoke to Baron, he suggested Permatex as well so hopefully this works (and I'll ask for the instructions to be revised).

 

Regards,

gp

[RedRider]

Another difficulty my be incorrect mixture in the carbs. While at Pork in the Pines, I did a ColorTune and it took care of my popping. Mind you, I have Bub slipons and still have my AIS installed. I was running very rich previously.

 

RR

[george_park]

Well after putting peratex sealer on it's better but not great.

 

The popping is only on decel/engine braking - under load and never under idle (or accelleration).

 

Goose had mentioned the carb caps - I've attached some pix, if these are they let me know. I took pictures of both sides, under the choke and directly opposite on the right side.

 

Other than that it's time for a carb sync or something else because I am out of other options (other than putting my AIS right again...).

 

gp

[flb_78]

Yep, those are the carb boot caps.

[Venturous Randy]

Great pics, George

RandyA

[V7Goose]

Yup, you found them, alright. I see that you still have the vacuum hoses attached that activate the AIS valve too (on each side there is one cap and one hose). For testing purposes, you should pull those hoses and cap all four ports with new caps and spring clips.

 

If you still have popping, I would then get some high temp RTV gasket goop (basically just a type of silicone) and cover all the open edges of the muffler joints, including the slits and around the end. This is only for testing; I know it will get all over the chrome, but it can be scraped off later without damaging anything, and that is the only way I would be CERTAIN that all leaks there were stopped. Just for good measure I would also pull the Y pipes and seal the two crimp points on both of them with JB Weld.

 

If you STILL have popping after that, I would find wherever you disconnected the hoses to the AIS induction ports on the heads and cover the plug and end of the hose in the same RTV. Again, that would only be for testing, as I would personally hook it all back up after I sorted out the problems, but coating the plug with RTV silicone would make absolutely certain no air was getting in.

 

Finally, if you STILL have any popping, I would have to focus on other vacuum leaks and possible problems with fuel mixture or ignition. Other vacuum leaks are easy to detect just by spraying carb cleaner all around the intake manifold on each cylinder while the bike is idling, paying particular attention to the joints between the manifolds and the carb and cylinder head. Any change in engine speed or sound will show there is a leak. If you can't find anything there, change the plugs and have a shop use an exhaust gas analyzer to properly set the mixture on each carb and then do a careful sync.

 

If after all of that you still have the problem, I would have to assume your mufflers are just complete garbage and toss them in the can! Actually, I would just put the stock pipes back on without touching anything else for the final test to prove it was the new pipes causing the problem.

 

Of course you can change the order of those tests if you want. I was simply listing them in the order that I think will likely find the problem the fastest. Good luck!

Goose

[george_park]

When I pulled the muffler I put Permatex sealer all over the pipe and muffler.

 

I used Permatex form a gasket 1B which has a max temp rating of 400F.

http://www.permatex.com/products/Automotive/automotive_gasketing/gasket_sealants/auto_Permatex_Form-A-Gasket_No_1_Sealant.htm

 

I'm not so sure that will last but have no idea how hot it will get back there... Do you think the sealer on there now will fail?

 

I did get new caps from the Yamaha dealer today, my existing ones did not leak, but I also went and put a little more gasket sealer on the pipes just in case.

 

I'll keep the existing caps and put them on the places where the hoses are now on the carbs - I've added a picture below to show what is where (it's the right side, not the left...).

 

Regards,

gp

Edited September 24, 2008 by george_park

[Guest Yamahawg]

Wondering what kind of Air Filters you have. I have K&N on mine. It was popping pretty good with Silver Bullet Exhaust on it. I cleaned and re-oiled the filters and popping stopped.

[george_park]

Just the stock filters. One of the techs I spoke with said that with the exhaust and filter change I may lean it out too much but I was still considering installing the K&Ns anyway...

 

Any idea how hot it gets just before the muffler? I can smell the permatex 1B cooking off a little, wondering if I shouldn't take it off and go with the high temp stuff.

 

gp