Kerker Race Only 4 into 1 Exhaust 1.5/8" vs 1.5"

Sir's

I was reading a few articles recently on KZ1000R S1 replica builds Vs. a real KZ1000 S1, and came across a statement about the Kerker pipe that was used by Muzzy.   This fella' said he purchased a Race/Competition only exact Muzzy replica exhaust from Japan, and that it used a larger diameter header pipe than the regular one we normal slobs get.  Also that this pipe gained 7 HP over the standard pipe.  That's a significant amount of gain from a pipe on a 100HP engine.  I think the article said the pipe was 1 5/8" vs 1.5", but I can't find the article again.   

Now the build this fella' did is the most beautiful and technically correct  S1 that I have ever seen.  Those that have owned the S1 or raced in the day might know if this is true, and if so I sure would like to get my hands on one. 

I figure Doc/Gamma/Bob might know, or Wayne from Oz. 

You can see the build on kz1000r.com,  Steve Willgoose's.

Thanks
577Nitro






 

I thought the S1s were around 140 h.p..


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wrote:

I thought the S1s were around 140 h.p..

 

Yes, but the base engine about 100hp.   

The trick is....what does the horsepower curve look like with the pipe?
You may gain 7hp but if you have flat spot immediately before or after 7hp gain then the 7hp could be more of a problem.
You should also make sure your pipe diameter matches up to the exhaust port in order to keep your reflected waves in the right place. Any change in diameter in the exhaust pipe creates a negative or positive pressure wave heading back towards the engine.
Bigger isn't necessarily better. It has to be bigger or smaller in the right places.



vintagebikemagazine.com/technical-articl...the-meaning-of-life/
excerpt-vintage bike magazine-Kevin Cameron