compression diminishes to nothing from 1 to 4

[niclpnut]

any autoparts store should have a lapping compound. Course and fine usually in the same package. Start with course and finish with a few turns of fine depending on how bad the seats are.

Nic

[Paul's Zuki]

alright, so far I have replaced the valve guide seal on chamber #4 and lapped both the intake & exhaust valves seats. Only got around to do one b/c I had to tear down, but after I was done I did the wet test by flipping them over and putting some lighter fluid in the dome to fill it up let it sit over night and no leak what so ever. So I feel that one has sealed correctly. Now, I did notice that my intake valve #3 had absolutely no seal at all. I did the light test and could see a gap of about 1/16 halfway around. Possible replacement of valves on that chamber?

[mike_of_bbg]

You need to tear down further before you'll know. You probably should replace those valves. Considering #3 is where you had a holed piston I'd say that seat has a good chance for damage as well. You may be headed to a machine shop to grind some seats, or pick up a good used head somewhere. If you grind the seat down that far then you'll need to shorten the valves some as well so you can get shims to fit it.

alright, so far I have replaced the valve guide seal on chamber #4 and lapped both the intake & exhaust valves seats. Only got around to do one b/c I had to tear down, but after I was done I did the wet test by flipping them over and putting some lighter fluid in the dome to fill it up let it sit over night and no leak what so ever. So I feel that one has sealed correctly. Now, I did notice that my intake valve #3 had absolutely no seal at all. I did the light test and could see a gap of about 1/16 halfway around. Possible replacement of valves on that chamber?

[Nessism]

Now, I did notice that my intake valve #3 had absolutely no seal at all. I did the light test and could see a gap of about 1/16 halfway around. Possible replacement of valves on that chamber?

Something seriously wrong there. Maybe the valve is bent?

As an aside, it's assumed that you will replace all the gaskets while the engine is apart. Suzuki OE gaskets are far superior to aftermarket. In particular, the base gasket and rubber O-ring seals on the base gasket are critical.

[Paul's Zuki]

I do have a new gasket set (oem). I do believe the valve is probably bent, I did look at the seat on the cylinder head and it looks pretty good, even the valve seat, but i do believe it is bent. I am going to order another. It was getting late last night, and only had a chance to work completely on #4, will start on the other three today and probably go ahead and order the valve tonight to once i see what else is there.

[mike_of_bbg]

You ought to be able to put one of the other intakes in there temporarily to see if the sliver of light goes away.

[Paul's Zuki]

You ought to be able to put one of the other intakes in there temporarily to see if the sliver of light goes away.

I actually thought about that last night, but because it was getting late and I was getting tired, I didn't want to screw anything up, really didn't want to lose any small peices b/c of clumsiness, so i just wrapped it up and went to bed. all seriousness aside, I had a dream the other night that I had the bike running. Since I've purchased it 3 years ago, it has not been turned on once. It's hasn't ran even before I bought and who knows how long before that.

[Paul's Zuki]

Ok just lapped all the valves and replaced two exhaust valves. I know I still need to get correct shims for at least 3 of the exhaust valves to adjust and will test compression then.

[Paul's Zuki]

Hypothetically speaking, as I have one more step to do before I test compression again and get a reading, If you have installed new piston rings, lapped and made sure valves seat good, new cylinder head gasket, and your compression is still low, what's the deal? Again this is just a hypothetic questions. I still need to install proper shim sizes.

[Paul's Zuki]

Ok. So no hypothecial anymore. I just replaced the shims that needed replaced and my valve buckets spin freely with the proper clearance as per the manual. I go to check the compression and this is what I get: #1-78psi, #2-20psi, #3-26psi, #4-30psi. What gives. I at least now have gotten my #3 to read now, but it seems there was no change on the others. I have lapped and made sure the valves seated good. new gaskets. new piston rings. Does anyone have an idea? what else I could do to troubleshoot?

[Paul's Zuki]

Ride it hard for a while, then see what happens.
New rings need to seat.

I have read that but I do I even get it on with so little compression? Just did the wet test dropping a teaspoon of oil and the compression went up on average an additional 5 - 10 psi.
here are the #'s

Dry/Wet:
1 - 78/85 psi
2 - 20/30
3 - 26/30
4 - 30/35

[Nessism]

Something is seriously wrong. I'd check the cam timing first. Next is to double check the valve adjustment. Lastly, something could be wrong with the rings you installed. I trust you honed the cylinders before installing the new rings?

[Paul's Zuki]

Something is seriously wrong. I'd check the cam timing first. Next is to double check the valve adjustment. Lastly, something could be wrong with the rings you installed. I trust you honed the cylinders before installing the new rings?

Aside from what the manual says and what I see on the engine with the cam timing it is perfect. Everything seems to line up great. I just replaced 3 valve shims that had no clearance and now all have clearance between .03-.08 mm as stated in manual. I did not hone the cylinders..........so, I guess I'll be doing that next and will recheck my piston rings(those are new).

[gearhead13]

You need to do a hone when using new rings...ALWAYS.
The compression #'s should be higher even without honing. How did the cylinder walls look?
Did you test the valve seal after valve lapping by pouring liquid in the ports and looking for leaks?

[Paul's Zuki]

Yeah, this is my first rebuild so obviously the learning curve is throwing a hell of one. Anyhow, The cylinder walls looked pretty decent no gouging at all, maybe glazed over from what I've read and how they should look and yeah, I just lapped all the valve seats and poured liquid and all good. no leaks. Even had to replace to bad exhaust valves.