Compression test result

M-Tech wrote:

With respect to the "tight" exhaust valves on 1 & 4, that's not an issue for leakdown testing. The tolerances are from a cold engine, meaning they will be tighter when the engine reaches temperature and everything expands with heat . . . there will still be an acceptable (but smaller) clearance that allows your valves to close. In other words, if you have any clearance right now (cold), your valves will be closed. Leakdown is a static test, where you physically close all valves and put the piston at TDC. There will be leakage, and you're interested, again, in the percentage. There won't be any leakage past your valves unless they're held open by carbon, burnt valves, bent valve stems, damaged seats, or your cam lobe is actually pushing the bucket down (minus, or negative clearance).

The other question you had was regarding the head gasket. That engine uses two gaskets: one for Cyl. 1&2, and one for Cyl. 3&4. This makes it unlikely that the compression differences are caused by head gasket problems--but raises the question of head warpage.

If it were my engine I would do a leakdown test just to help pinpoint problem areas for special attention. Others may disagree, but I have been burned too many times getting jobs other technicians have not thoroughly diagnosed by beginning with the basics.

When left to use my own process, I pinpoint every problem (or potential problem) I can before I tear into anything. Your rich running condition can be caused by a number of things, and if you just rebuild the engine without determining all that you can before you tear it down you may be tearing some of it apart a second time. The same is true of your hot soak condition: is it caused by valve clearances for the hot engine, or flooding? Since your plan is to replace the FI for carbs, a misbehaving FI system won't be a concern . . . but if the spark timing was part of that problem, now is the time to know it, IMO.

Best of luck.

Joe

Thanks for all your comments.

I've done the leaktest (mainly just to see if my leaktester was working!).

It shows that all exhaust valve was leaking. Around 30-40 psi.

I will keep all your advise for later since I've decide to talk the other motor I got in hand from a kz1000J.

This motor has been bore once and haven't got a lot of millage since.

The only problem is that it has been sitting for 4 years.

I've tear down the top end this week end to see how it looks like. A mouse has done is house in one of the cylinder.....so cute :blink:

I've check all cylinder, piston and rings and everything is within spec.

Gonna have a valve job done on it to clean everything up and change seal since probably dry.

Gonna check Cam chain has Wiredgeorge recommand.

I'll keep the GPZ motor for winter project 2008-2009. Thinking of using my KZ1000J frame and install the GSX Swing arm and probably upgrade front end to have a nice everyday bike.

Thanks again.
Joce

Since it has been ask, here are the numbers for the valve clearance:

Exhaust:
#1: 0
#2: 0.002mm
#3: 0.004mm
#4: 0

Intake:
#1: 0.002mm
#2: 0.003mm
#3: 0.003mm
#4: 0.005mm

Clearance should be between 0.002-0.006

Does this help narrowing the problem?

No that didn't help me any. The numbers you gave; check to be sure if they are in inches or millimeters. I never make any measurements in inches... The KZ1000J spec is .05 - .15mm - You have NO clearance on two valves. This means that the CAM SHAFT LOBE MAY BE HOLDING THEM OPEN. Adjust your valve clearances as I have noted before else you may end up going in the wrong direction trying to fix what may not needed fixing.

coffee please!!!!!

The measurement I've mention are in inch.....................

So the clearance spec are the same you gave me. Sorry for this confusion.

I'll adjust those valve and give you the result shorlty.

Thanks and sorry for waisting your time. I gonna make a strong coffee right away!