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Discussion Starter · #1 ·
Hi everyone. Recently I traded a guy for a 1992 GSXR600W that couldn't get it started. Seemed like an easy fix so I brought it home. However, it has turned in to quite the project.
Here is what I've done:

Drained the tank, rebuilt petcock and verified operation, installed new fuel.
Rebuilt carbs, set float height at 15mm, cleaned all jets, set idle circuits to 1.5 turns out, verified operation of variable venturi slides, etc.
Drained the crankcase full of fuel/oil mix and installed synthetic oil.
Verified crankshaft signal generator at about 150 ohms.
Checked spark plug gaps. 0.6mm.
Checked CDI box for power, ruling out neutral switch / sidestand switch.
Checked ignition coil resistance and checked for an 8mm spark as per the manual. Got a pink spark at 8mm through the wires by butting up the spark plugs and clamping them at the proper distance, then cranking the engine.
Adjusted valve lash. Lash was way off, even after installing thinner shims I am still on the low end at .009" intake and .015" exhaust. Intakes originally measured 0, exhaust .01".
Verified cam timing as per the manual when reinstalling cams.
Battery is new, and I have charged it back up a couple times since I've been running the starter so much.

I tried pulling the carbs back and spraying starting fluid directly into the intake ports, and cranking the motor. Nothing but a little sputter once in a while. I have a crap compression tester, and it's only showing about 40lbs pressure. I figured it was giving me a bad reading so I built an adapter to pressurize the cylinder with compressed air. Cylinder #1 has an exhaust valve leak, but the other valves are good and tight. All cylinders exhibit blow-by through the crankcase though. I think I used about 50psi, and you could feel/hear air through the crankcase.

I pulled the cylinder head and cylinder block and found evidence of a failed head gasket. Apparently water had stood in the cylinders for a while, because the rings were all corroded and stuck in the piston ring grooves. Hence the low compression.
I pulled the wrist pins and inspected the pistons, they show pretty much no wear at all. Same with the cylinder walls, there are still honing marks where the skirt of the piston makes contact, most of the honing marks are gone where the rings contact the cylinder wall though.

I totally don't understand these pistons. They appear to be aluminum which I didn't think was possible. They also fit really loose in the cylinder at the crown of the piston. The skirt is tight, and the manual says to measure the skirt. The cylinder/piston gap at the measurement point is only a couple thousandths of an inch. But there is probably .020" gap at the crown to the cylinder wall. Crazy. I can't find a 1992 600 manual so I don't know what the actual numbers are supposed to be. The manual I have for the 750 says not to check the piston anywhere but 15mm from the bottom of the piston. I guess the crown of the piston just floats in the cylinder, centered by the piston rings which actually touch the wall. Makes sense since otherwise the aluminum would wear quickly.

So I'm going to re-ring the pistons, install a new head gasket, cylinder gasket, o-rings, etc. and then get some thinner valve shims. I plan on just lightly running some 1000 grit sandpaper in the cylinders to get some crosshatch since I don't know if the rings are chrome moly or cast iron. I can't find any reason for the head gasket failing, the cylinder block and cylinder heads check out with a straightedge. I was thinking about using some of that spray copper stuff on the head gasket. I also read I need to change out the oil for mineral base while the rings break in.

I've been thinking hard about trying to put all the plastics back on since they came with the bike, but the more I look at it the more it just looks like way too much work. All of the brackets are bent. The panels were rattlecanned over the stock paint and graphics. The front cowl was cut and the windscreen is from a different bike. The mirrors don't fit because of that. Most of the fasteners and rubber grommets are gone. The headlight mounts are broken. You get the idea. I finally gave up on that and have a streetfighter in mind. I'm getting more excited about doing it that way, I've got some ideas. I used to work on aircraft so I've got some decent skills. We will see. I'll post when I get it sorted out.

Finally here is what it looks like right now.
 

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Discussion Starter · #2 ·
Well, I've been living in the garage every night for a while now. Finally got the engine sorted. Lots of little tweaks here and there, this bike has been badly neglected. It's almost to the point where I am going to just ride it for a while. Eventually I'd like to trim the tail a bit. I also want to strip the ugly rattle can paint from the tank. Here's what it looks like at the moment.



 

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UnicycleMode
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7,584 Posts
Surprised nobody replied. :confused:




The '92 GSXR600W's became a rare breed due to the construction of the head gasket, I've come across 4 of them now with the exact same issue. Power of deduction and all that pretty much draws up a picture of the head gasket construction being poor in one way or another and causing it to either shrink or burn through after enough time, as they systematically failed in the past few years in droves. Damn decent considering it was the first of the W's and the technology was rather new to production Suzuki sportbikes at the time too. No worries though as a replacement gasket and some time in the shop, as you have found, results in a bike that is ready to get back to street duty.


The fighter look is sexy on those slingshot frames, as cool as the plastics do look I prefer a naked one to a fully faired one in all honesty.






Being this is the welcome section you may not get as much traffic as you would if you posted up the build process in the, "member project bikes" section.

:thumbsup:





Welcome to CF by the way! This place looooves GSX-R slabbies and slingshots!
 

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lb/hp is what it's about!
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10,448 Posts
Welcome.

Ive got one of those 600w frames that I started a build with. Currently has newer gsxr usd forks, 929 front wheel and rotors, 900rr swingarm, 929 rear wheel, R1 shock with custom linkage and mounts, a oil cooled katana 600 engine, and a custom subframe and tail that hasn't been worked on in months.
 

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The Glistening Turd
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2,983 Posts
Welcome bud, I also have one of those frames with an 1100 engine in if I ever get back to finishing it.
 
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