Hayabusa Muffler

[Anonymous]

I thought the 4-into-1 Vance & Hines on my 750 was too loud even though I repacked it, so when a friend of mine offered me one of his spare Hayabusa muffles I took it. Not only is it quieter, but it flows better according to my sparkplug color. Whereas before the new mufler I was running rich, now I'm running slightly on the lean side and ther seems to be more power.

Harrison

[Anonymous]

That's cool, especially since Busa slip-ons are a dime a dozen on the net!

[Anonymous]

I used a Yamaha R1 canister that I got off Ebay for $25 on my '80GS1000s. I'm not sure about top end power, but mid acceleration improved. Also, it now has a nice low rumble rather that the spitting sound of the stock exhaust. :twisted: Doesn't look bad either.

[Anonymous]

Any of you guys have pics??

[Anonymous]

Thats cool,Do you think it would work on my 83 1100e? I need to repack mine and well it just aint cutting it.

[Dink]

Yes it would the only difficulty is you need to get a flange welded onto the end of your existing exhaust , as the Busa muffler is flange mounted.
Dink

[Anonymous]

The 'busa has two mufflers for 1300cc, so I doubt that one 'busa muffler would flow enough exhaust for a GS1100. I would think that 750cc would be the largest you want to flow through just one of those cannisters. I lucked out in that the midpipe on the 'busa exhaust system fit exactly on my 4-into-1 header. The 'busa cannisters and midpipes would be great if you could make them fit a 4-into-2 system.

Harrison

[Dink]

I know of several Katana 1100's that are running a single Busa muffler on a 4 into 1 all report an improvement, it is about flow, not the capacity of the motor.
Dink

[Anonymous]

Great, Dink. I had just figured that the cannister might be too restrictive for that volume of flow, but apparently not. Anyway, I was going under the assumption that if the 'busa cannister could flow 1/2 of the 1300ccs at 11000 rpm, it ought to flow my 750ccs at less.
The midpipe I'm using has a bracket welded to it, but I had to grind part of the bracket off in order to clear the brake pedal. I will try to post a picture as soon as possible.

Harrison

[Anonymous]

I had just figured that the cannister might be too restrictive for that volume of flow, but apparently not.

Another way to look at it is that the Busa makes 160+hp with two of those mufflers, so each will flow enough air to accomodate about 80hp with no troubles. If your 750 doesn't make substantially more than 80hp you should have no problems with it. As Dink said, this can vary some. The Jap bikes lately have gotten really good at making power with no noise, so almost any OEM can from a late model sportbike will flow a lot of air with not much noise, if that is your goal.

[Anonymous]

My '79 GS 750 didn't make 80 horses when it was brand new. Now,25 years and 30+K miles later, even with a K&N filterbox filter and the 'busa exhaust, I don't think it's approaching that figure. The reason I put the 'busa exhaust on the bike was not so much to gain horsepower, but to reduce the noise without reducing the power.


Harrison

[Hoomgar]

I find this very interesting Harrison. Thx for sharing
I want to see the pics. I may do this to my V&H pipe
just as a cosmetic upgrade.

[fast eddie]

Lets see some pics of the Busa mufflers guys?!

Seems like a neat idea, although I'd go for 4-2 on my GS1150, for flow reasons, plus I also like the symmetrical look.

[Evil Hobbit]

Re: Hayabusa Muffler

I thought the 4-into-1 Vance & Hines on my 750 was too loud even though I repacked it, so when a friend of mine offered me one of his spare Hayabusa muffles I took it. Not only is it quieter, but it flows better according to my sparkplug color. Whereas before the new mufler I was running rich, now I'm running slightly on the lean side and ther seems to be more power.

Harrison

Got a picture of how it looks? Did you slip it on the V&H header?

[Anonymous]

Why does the larger canister flow better (for a given exhaust tip diameter-that is)....

BECAUSE.......

(From another post): Did you know if you make a given air box volume larger, that you may have to rejet for lean condition? Guess what...the same works for EXHAUSTS. If you make the volume of the exhaust canister larger but do not change the tailpipe opening, the bike may lean out also?. This is because the RESERVOIR of air, whether either in the canister or the airbox, is larger, and remember air is COMPRESSIBLE, so a larger volume is able to absorb PEAK pressure pulses better, so the engine "thinks" the airbox or canister is LESS RESTRICTIVE.

Picture taking the exhaust from your bike and running it into a closed, airtight room, then exhausting the room though a little 1" diameter pipe. Sound restrictive? Not at all. You wouldn't hear anything out of the little pipe nor would the bike be restricted.....because the room would be so big, it could absorb the pressure pulses. The engine would "think" it was connected to no muffler at all.

How do I know - engineer - how else do I know - I played with airboxes and exhaust canisters.

And so, airbox and exhaust canister SHAPE, VOLUME, LENGTH, inlet and outlet opening sizes, the shape of the inlets and outlets and shapes of "transitions", ALL affect air flow - otherwise known as INTAKE TUNING... TUNING and it's RESONANCE affect the ability of an intake system to flow.

Frankly, I prefer leaving the air box on and opening it up so the inlet matches the outlet in square inches, then in with a K & N cone filter. I retain more midrange this way.

Did you know that any time a pressure wave hits a transition, whether it is from the 4 into the 1, or from the tailpipe tip to the outside air, that you get a REFLECTION pulse wave that bounces back toward the engine?

Yep - that is why the megaphone design, or smooth bends are best, or blending the diameters of the pipe with the head ports is important, or making sure the exhaust canister size is large enough to absorb these reflected pulses.

Look up a book called Design of Intake and Exhaust Systems. Tells you alot. Like the runner length, the minimum diameter of the collector pipe should be on a header. That the exhaust canister should be minimum 10 times the swept volume of one cylinder and on and on. Cool stuff. -Dieter