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View Full Version : 1990 GSXR1100 - what should compression be?


ACT_Cross8
17-06-2009, 10:01 PM
I'm close to purchasing said motorcycle (sort of reliving my youth, but that's another story...). Due to age (of bike, not me), I want to give it a compression test to make sure it's reasonably healthy before I sign up.

Can any mechanic or person with access to a workshop manual please let me know what the compression should be? Are there any other peculiarities with this model that I should be looking for, apart from the usual maintenance-type items?

Thanks in advance.
wikky
18-06-2009, 10:54 AM
Are you chasing a cylinder compression (psi) or the compression ratio? The comp ratio of this bike is 10:1 if that helps.

Ok, just looked up some more info. Stock compression for each cylinder should be bewteen 170-199 psi. Also hope this helps .
ACT_Cross8
18-06-2009, 07:10 PM
sorry, cylinder compression. thanks for that.
Gosling1
24-06-2009, 01:58 PM
Hi X-8.....mate I am local here in ACT, do a bit of work on old jap stuff, and can get your cylinder compression tested pretty easily...

When new, as old mate has pointed out, these bikes should run about 170psi or higher. They can run as low as 130psi without any drama, as long as *all* the cylinders are pumping the same compression. If one or more is running significantly lower than the rest (which in old kwakkas is alwasy #3) - then you may need to have a closer look inside the motor to find out the reasons - there could be a few.

As far as other common issues with the old GSX 1100's - they have always had problems with the reg/rectifier units. These fail and you then get problems with alternators burning out, and batteries failing. These units are easily checked though. The engines are bulletproof for the most part. Its getting harder to locate decent bodywork for these......apart from that, a good GSX1100 is a great bike with plenty of mumbo...

If you want to shoot me a pm, I can come around and have a look at your bike if you like. I do a lot of jobs like this for members of the local ACT bike forum, CanberraRIDERS. Especially the older stuff.......

cheers
Gos