^^ correct, pull the baffels and you will get that sound.. it does get annoying though

 

OK, then it sounds like you're talking about a different sound than what I was thinking of.

I'm still not sure what you're talking about though. I've heard Jacobs brakes (and many other brands of un-muffled compression-release brakes) and I've never heard a bike make sounds like that. The stereotypical "jake brake" sound comes from a diesel venting air at the top of the compression stroke directly to atmosphere without any muffler system. The way a gasoline engine's valvetrain works you can't get the same setup and unless you've got straight pipes, even with a diesel's valvetrain you won't get the same sound.

The closest thing I could think of would be a tune that completely shuts off all fuel flow when the throttle is closed and the engine is above a certain RPM. That would get a result closest to what's happening in a diesel engine when a compression brake is used. I'm not sure how good that is for the engine though.

 

He is talking about the sound a "18 wheeler" makes when coming to a stop, or slowing down. It is called a jake brake short for Jacobs brake that is actually a compression release thru the exhaust making that loud BRRRRRRRRRRR sound.

If you remove the baffles on a straight pipe it will make a similar sound when you let off the throttle which is caused by reversion.

Reminds me of my high school days and glass packs!

 

Mine does the jake brake sound if i get it reved way up in first or second gear then just drop to idle. It gets everyone's attention. I think it sounds cool when you race light to light.

 

I'm reviving this to say "thanks" and to let people know, the new VH OS 450s will make this sound.

 

I have OS450, FP3 and S&S Power Tune Duals. I'm getting the Jake Brake sound and assuming it is normal and not a bad mixture.

[QUwOTE=cmstewart72;14526962]I'm reviving this to say "thanks" and to let people know, the new VH OS 450s will make this sound.[/QUOTE]

 

My carbureted 2006 1200cc with straight pipes did the jake brake decel and I loved it. Best sounding HD I ever had, IMO.

 

 

+1 When I had a clogged pilot jet issue, it made my bike do that on decel, which is why I always believed it was a lean condition, not rich.

John