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View Full Version : 2007 Kawi ZX6R 13.9-1 Comp. Rat?


GSXR05K
02-16-2007, 02:59 AM
Hello,

Has anyone confirmed the compression ratio for the new Kawasaki ZX6R sportbike?

What I'm reading is 13.9 on the Kawi website!

Thanks, Aaron
fsae.sdsmt.edu
Bill Kunst
02-16-2007, 06:17 AM
not through testing, but I heard the same.
BeaverGuy
02-16-2007, 10:45 AM
As it isn't a new motor, same one from the zx6rr, and their hasn't been any complaints for false advertising I would believe it. What I find more intersting is that they appear to have dropped the 636 which was the ZX6R and made the limited production 600 which was the ZX6RR the ZX6R.
ScottW
02-16-2007, 10:57 AM
I beleive it's 13.3:1, though I may be wrong.
Bill Kunst
02-16-2007, 02:08 PM
Its rediculous:1 if you ask me. I never thought that I would see anything over 12.5:1, or very close, on the road even in cycles. The combustion chamber and piston must be perfect, i gots to see it my self.
VFR750R
02-16-2007, 08:26 PM
I agree, the precision of machining and extra efforts required to get that kind of compression ratio especailly with engines moderately to excessively oversquare is extreme.
I would not be surprised to find that that is a nominal value and measured would be less, but considering the efforts taken to get close to that means engine to engine variance is likely to be small as any error in one direction could easily be error in the other. Any Piston to valve touching reduces engine life to less then streetable.
John Stimpson
02-23-2007, 05:17 PM
I don't think ~13.5:1 compression is so unreasonable... Consider the smaller the bore, the less chance of "abnormal combustion". Also, higher engine speeds lessen the chance of detonation. Lastly... Big, rowdy, high overlap cams can easily knock a static compression ratio of 13.5:1 down to a dynamic ratio of 9:1.
VFR750R
02-23-2007, 07:11 PM
Rowdy big overlap cams lessen P to V (piston to valve clearance) making it harder to attain static compression ratios that high. Getting 13.5:1 on an oversquare engine is no easy task.
Krautsalat
02-24-2007, 02:21 AM
In a test of a magazine the CR of the new ZX6R was given as 13.3:1, which would be pretty good fo a mass produced engine with tha bore to stroke ratio. From my own experience I can say that the advertised CR is not always correct. A 2003 ZX6RR should have a CR of 13:1, when mesured it was more like 12.6:1.

Krautsalat