Author Topic: Bafflectomy  (Read 21008 times)

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Offline mattchewn

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Re: Bafflectomy
« Reply #175 on: July 06, 2016, 10:28:49 am »


I disagree, with all due respect.  It wasn't until I did the bafflectomy that I began getting deacceleration pop.  It may be a coincidense, but I don't think so.  Deacceleration pop is mainly due to a lean fuel mixture which can be caused by a variety of things, but I find it odd that it began happening the day I did the pipes.  In fact, I still have the same problem even though I have since switched to Delkevics.
[/quote]
Actually Rick,
The decal pop is NOT from a lean condition but actually a RICH condition. Lean would mean no fuel to burn in the exhaust. Since all bikes are set up rich from the factory one of the only things that keeps them from popping on decal is the back pressure of the stock restrictive exhaust systems. the bafflectomy removed some of that restriction and there you are now it pops!
Matt

( I make my C14 pop on decal on purpose! I like it! )
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Offline rick

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Re: Bafflectomy
« Reply #176 on: July 06, 2016, 12:19:15 pm »
Ok, so I was close.

I actually stopped the pop when I installed the block off plates, which to me, means I had an air leak in all that unnecessary plumbing.  The air leak, to my way of thinking, would have leaned out the mixture.  Be that as it may, the pop started again at some point and I don't know why.  I just live with it until I one day get PBFoot to adjust my pilot screws.

Offline rick

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Re: Bafflectomy
« Reply #177 on: July 06, 2016, 01:34:22 pm »
This is where I obtained my understanding of the decel problem.  I think my experience with the block off plates indicate I was running a little lean, which, according to the explanation below, would make sense.



If you think about the mechanics of what is going on upon decel, it makes perfect sense:

You start out with an engine that is turning high RPM with a carb that is open, flowing freely. Next, you close that slide. This has the effect of creating a tremendous vaccuum in the intake manifold (CHOKE!). This vaccuum does curious things:

1. It pulls air and fuel from wherever it can--including the idle and low speed jetting in the carb.

2. To counteract the vaccuum, air will take the path of least resistance--including sucking exhaust gases back into the combustion chamber during valve overlap (the brief period of time that the exhaust and intake valves are open at the same time.

So what does this mean? Well, now you have a disproportionate rich mixture heading for the cylinder AND what little oxygen is drawn in is further diluted by gases that are coming back into the chamber from the exhaust valve. The result is poor, incomplete combustion! Depending on the temperature of the exhaust pipe and gases, reignition is possible once this mixture is introduced into a more oxygen rich environment. This produces the "pop."

Why does a lean running engine have a tendency to excessively pop? The exhaust gas temperature of a lean engine is substantially higher than one that is running on the rich side ( an EGT probe will show this). Therefore, the high EGT serves to heat the pipe more and the gases themselves become a much better source of re-ignition. By richening things up, you are cooling down the exhaust temp and therefore reducing potential re-ignition sources.

Any 4 stroke engine--even those that are flawlessly tuned will pop on decel. It is harmless, but can be annoying--granted. However, I would never alter the jetting of an otherwise performing motorcycle to get rid of it. Go by the seat of your pants and the color of your spark plug rather than the popping as an indication of the jetting of your scoot!

Offline Taffy

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Re: Bafflectomy
« Reply #178 on: August 26, 2016, 04:31:05 pm »
After reading the many posts on this subject I have decided to undertake this mod on the "Grey Flicker". I will update on the results.  :motonoises:
1987 C-10 "Grey Flicker"
1980 750 GSL Suzuki "Betsy"

Offline connie_rider

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Re: Bafflectomy
« Reply #179 on: August 26, 2016, 04:38:15 pm »
I had Cobra's on my C-10 and got tired of the loud.
Installed stock with baffelectomy recently.

With the Cobra's the bike had noticible decell pop.
Didn't notice it with the baffelectomy. hmmmm
(May because it is so much quieter though)..

Ride safe, Ted
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Offline Bob_C_CT

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Re: Bafflectomy
« Reply #180 on: August 26, 2016, 05:55:02 pm »
I got the cobras now. Not too loud. Years before installing them I put block off plates on and had bafflectomized OEMS and started to got the popping on deaccel. Now with the cobras the popping is a little louder.
 So if I'm riding in neighborhoods early morning or later at night I try not to deaccel too much by downshifting.
But twist of the wrist in rural and highways and the cobras growl nicely.
97 C10,ZRX Front, Meanstreak rim

Offline VTconnie

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Re: Bafflectomy
« Reply #181 on: August 27, 2016, 05:24:15 am »
I had Cobra's on my C-10 and got tired of the loud.
Installed stock with baffelectomy recently.

With the Cobra's the bike had noticible decell pop.
Didn't notice it with the baffelectomy. hmmmm
(May because it is so much quieter though)..

Ride safe, Ted

After a long trip with 14" Delkevic's, I kinda wanted the OEM's with the bafflectomy back on there for that. But I also like having a nice exhaust note when traveling, sometimes people need to hear it.
<--2003 Concours C-10 "Conifer", -AKA- The Cruise Missile
1980 CB900C DOHC "Old Iron" -AKA- The Hill Climber                

Offline cag

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Re: Bafflectomy
« Reply #182 on: May 28, 2018, 04:09:30 pm »
I know this post is a few years old but I wanted to give my 2 cents worth on it.
I recently took a chance and drilled a hole in the baffle of my exhaust. It is only a slightly louder but a little deeper in tone. I noticed on a recent trip with my wife and I and helmets that it resonated more than before. It was not annoying but it did hum in the helmet more than before. If this was all I noticed I'd say that it was worth the $20 I spent on the right sized hole drill bit. However I think others have noted a difference in acceleration. I did as well. It seemed to breath more freely in the midrange but I felt less torque, so honestly it felt less powerful. This is a drawback.
I was going for a better sound. I think the older I get and the more mechanical the more I like the sound of a motor. The four cylinders like these are smooth and do have their own feel and sound to them but to me it's not much more than a economy car. I also have a VFR750 and if I could make it as comfortable and practical as the connie I'd prefer it. Love the sound it has with my aftermarket pipes. I just want something with a little more grunt sound to it with a thumpy feel rather than a buzz. Just my opinion.
Other than that my connie is great and my wife loves it. It's a beast to get out of the garage and move around a parking lot but it's great once it gets going. I'll be sticking with it for some time I think.

Offline SteveJ.

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Re: Bafflectomy
« Reply #183 on: May 29, 2018, 05:14:58 am »
Someone did a Dyno comparison a few years back. It showed 1-3 gains at all rpms on hp and torque. It also helped fix the torque slump just under 5k.
Yeah, if you want true ram air tuning, you better be willing to ram some air! (SiSF)
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Offline dimetraveler

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Re: Bafflectomy
« Reply #184 on: May 30, 2018, 12:25:30 am »
i did it and liked it,no regrets any body who wants to do it i will send you the the Bit
 used  once at my convince.Snail mail as soon as i can.
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