Topic: MotoGP Werks pipe on Naked Speed

[SOHC4 Cafe Racer Fan]

Looks like Dustin Kott ran one of Chris' pipes on his tv show bike MINUS the second end piece aft of the collector. The Boz Brothers said it was loud, but it probably lost a lot of performance with the absence of any back pressure.

[Trad]

Looks like Dustin Kott ran one of Chris' pipes on his tv show bike MINUS the second end piece aft of the collector. The Boz Brothers said it was loud, but it probably lost a lot of performance with the absence of any back pressure.

Fashion over form in this case Don. Bet it sounded pretty mean. 

[SOHC4 Cafe Racer Fan]

I didn't see any spring clips attaching the pipe to the head, but the finish of the pipes sure looked close to Chris' product.  I'm sure it was loud, but I'm not a fan of obnoxiously loud pipes for a street bike.  With race bikes, I don't mind them.  I like the function to drive the form.

[calj737]

The pipe in that picture does not look like a current set of Chris'. They are missing the exhaust clamps, perhaps an older set? Or a new Carpy 4:1 in stainless? Or is it Lossa offering that now...? Either way, without a tailpipe, what's the frickin' point?

[SOHC4 Cafe Racer Fan]

I'm with you, Cal.  You lose power by eliminating the tail pipe.  If the purpose is Naked Speed, there goes your speed.

I doubt it was an early version of the pipe, since Chris has been making his current design with the spring claims for a couple of years now (and Kott just built this bike last year).  Lossa (Jay) will make it in stainless, too.  Of course, Kott may have just gone to one of the manufacturers and had them build one like this (without clamps) or taken a MotoGP and removed the clamps.


Note: on the show, the Boz Brothers didn't make any remarks about the handling or speed of the bike, just the sound of the exhaust.

[bwaller]

That must be a new helmet style.

[Geeto67]

That must be a new helmet style.

I believe davida calls that model "The douchebag".

[Trad]

After dealing with Dustin and having sub par service and hearing some stories of first hand encounters with the guy, he seems to be building a not so great reputation. I am out to lunch on that statement?  I really dig the look and style of his bikes but running no tailpipe is just goofy.

[slikwilli420]

Don't want to much performance from the pipe. The brakes probably already had plenty of trouble keeping up. Sad tosee bikes go backwards in tech that far .

Side note,  every time Mike Seate opens his mouth he sounds more out of touch with the entire hobby.

[Retro Rocket]

I'm with you, Cal.  You lose power by eliminating the tail pipe.  If the purpose is Naked Speed, there goes your speed.

I doubt it was an early version of the pipe, since Chris has been making his current design with the spring claims for a couple of years now (and Kott just built this bike last year).  Lossa (Jay) will make it in stainless, too.  Of course, Kott may have just gone to one of the manufacturers and had them build one like this (without clamps) or taken a MotoGP and removed the clamps.


Note: on the show, the Boz Brothers didn't make any remarks about the handling or speed of the bike, just the sound of the exhaust.

Chris makes his pipes in house now, I think if you ask Jay at Lossa you'll find he uses the guy that used to make Chris's early pipes, I think Carpy still uses him too...

[MRieck]

The pipe looks stupid without the rear section

[Retro Rocket]

The pipe looks stupid without the rear section

Amen....

[SOHC4 Cafe Racer Fan]

The pipe looks stupid without the rear section

Amen....

I guess the hipsters don't have a clue.

[Retro Rocket]

The pipe looks stupid without the rear section

Amen....

I guess the hipsters don't have a clue.

I'm guessing your correct....

[754]

Now you got me wondering why the car guys always unbolt at the flange,  rather than 18 inches back?

[Geeto67]

Now you got me wondering why the car guys always unbolt at the flange,  rather than 18 inches back?

because it is easy. Also that really only happens on large, pushrod, oversquare v-8 engines running massive overlap cams. You don't see a lot of that practice on square or undersquare multi overhead cam 4 cylinder import engines.

[johno]

I agree,  the short pipe look doesnt look right
BUT , in regard to a couple of comments, ie need back pressure for performance;  back pressure is the enemy of performance in all exhausts, the back pressure being a good thing is generally accepted as being in relation to early volkswagons getting a leaky exhaust or a modified exhaust that resulted in burning the seat on the exhaust valves , especially the cyl behind the oil cooler.......that evolved in the 70's encouraging people to say no back pressure causes problems where in reality it is the complete opposite,     Re the tailpipe length it certainly does have an effect on performance , in general the shorter the length after collector the higher the RPM peak torque curve, the longer the length the max torque occurs at lower RPM.

Re the old days of drag cars unbolting their headers at local drags , lots of cowboys done that for the noise, the smart players either had the flanges further back or they bolted short extensions on, especially the bigger heavier cars having launch issues looking for lower RPM peak torque

Thats my two bobs worth, cheers johno

[MRieck]

I think it is in Kevin Cameron's first book that he mentions Rob Muzzy favorite exhaust for all out power was a 4 into 4 open pipe system.

[Tintop]

I think it is in Kevin Cameron's first book that he mentions Rob Muzzy favorite exhaust for all out power was a 4 into 4 open pipe system.

That was Honda's take with their early race bikes like Hailwood's 500 & the 250/6.  Problem is ground clearance with all those megas stacked up.

[NalleyRacing]

I think it is in Kevin Cameron's first book that he mentions Rob Muzzy favorite exhaust for all out power was a 4 into 4 open pipe system.

Do you think this is true in a drag scenario? I have wondered why they call 4:4 "drag pipes". I  have a set of 4:4 open pipes and a RC performance exhaust.. I'm interested to see what the difference's are

[Geeto67]

back pressure is a "red herring". What one is concerned about is exhaust gas velocity. The smaller or more restrictive the pipe is the faster the velocity but the smaller the volume, the larger and less restrictive the pipe is the slower the velocity but the larger the volume. the fictional ideal pipe balances velocity and volume to the chamber and valve's flow characteristics in the entire RPM range (because higher RPMs require different velocity than lower ones). When an engineer designs a pipe, he selects a range of RPMS he want's to optimize for and builds a pipe that flows within a range of velocity and volume to meet those requirements from the head pipe to the tail. When some dipswitch builder removes a large section of that pipe he disrupts the engineering behind it and changes the velocity as well as any noise restriction that may be there. Most people talk about this as removing necessary back pressure and maybe they are right if opening the pipe causes velocity to change, but it is not always the case. as many examples prove you don't need "back pressure" you need a pipe suited to velocity and volume requirements.

[Retro Rocket]

back pressure is a "red herring". What one is concerned about is exhaust gas velocity. The smaller or more restrictive the pipe is the faster the velocity but the smaller the volume, the larger and less restrictive the pipe is the slower the velocity but the larger the volume. the fictional ideal pipe balances velocity and volume to the chamber and valve's flow characteristics in the entire RPM range (because higher RPMs require different velocity than lower ones). When an engineer designs a pipe, he selects a range of RPMS he want's to optimize for and builds a pipe that flows within a range of velocity and volume to meet those requirements from the head pipe to the tail. When some dipswitch builder removes a large section of that pipe he disrupts the engineering behind it and changes the velocity as well as any noise restriction that may be there. Most people talk about this as removing necessary back pressure and maybe they are right if opening the pipe causes velocity to change, but it is not always the case. as many examples prove you don't need "back pressure" you need a pipe suited to velocity and volume requirements.

Bingo....

[Geeto67]

I think it is in Kevin Cameron's first book that he mentions Rob Muzzy favorite exhaust for all out power was a 4 into 4 open pipe system.

Do you think this is true in a drag scenario? I have wondered why they call 4:4 "drag pipes". I  have a set of 4:4 open pipes and a RC performance exhaust.. I'm interested to see what the difference's are

They call them drag pipes because it is how they look - like short open headers. Back in olden times when dinosaurs pulled the rails to the strip drag racers didn't have to worry about noise restrictions so they just built pipes to their power needs. Dedicated dragsters usually run high compression, large cams, and the useable power is higher up the RPM range. So they need a short pipe, mostly because the high compression is pushing out the gas as fast as the cast port in the head can handle. Street pipes were designed to just be loud and open and look like racers pipes, no real engineering in them for maximum power. Ever put drag pipes on a sportster? esp an ironhead sporty? they lose power because the exhaust as velocity is too slow for the stock ports.

Every pipe has it's right set of circumstances. An RC race header has very different requirements for port flow than an RC street header. The secret is knowing how to do the math and having tools like a flow bench at your disposal to maximize power.

[johno]

yeh all that stuff is right,  in a nut shell,  for a racing exhaust ....zero back pressure ( smallest diam without creating back pressure) and tuned length for the assistance exhaust cam timing provides at what RPM your diggin it.

No one has commented on it yet but if you want to see a decent bike exhaust with the latest F1 exh technology check the pipes on my         " too busy to help me friend" Kens new drag bike.   He is running the stepped UP staged primaries like the current F1.

I dig good stuff like that

[Fastbike]

johno,

Do you have a link to that exhaust system?  I'd like to see what your talking about.  Thanks.