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Discussion Starter · #1 ·

Recently I dynoed my 05 GSXR 600 (5000km on the clock). No mods except TRE. The results came out rather low:

The A/F ratio is very rich

I thought something might be not right, hence did some checking.
1. Compression pressure test
It failed the service manual's minimum (128psi). I got 127.5psi for all cyclinders.
I have tested the pressure gauge against my dad's CBR1100XX and the result was higher (147.5psi).
This is most puzzling as GSXR have 12.5 compression ratio and the CBR has 11.

2. Leak down test
The result is excellent. 3% leak for all cyclinders.

I'm just wondering if you guys have any opinion on this? Do you think the valve timing or the valve clearance is out?


· Registered
1,044 Posts
Maybe because it was tuned by Marilyn Manson?

That does look a little low, but then again maybe not. If your at a high altitude it will dyno lower, and weather conditions affect it also. And if you know it's way rich obviously that isn't a good thing. Dyno tune should fix that easy enough though.

I seriously doubt you have low compression, especially since the leak down test is good and all cylinders check the same, although I guess anything is possible. There are other factors that affect the compression readings besides compression ratio (valve timing and overlap for example).

I'd get it dyno tuned and see what you can get out of it. And find out what other gixxer 600's are dynoing on the same dyno with similar weather conditions so you have something to compare it to.
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