GS850 Fix-up

[Guest]

So I bought my first street bike, and since I want to learn how to work on engines I bought one that needed some work. I've gone through it and rebuilt the carbs, adjusted the clearances, the whole nine yards. I used to have good compression in all cylinders, but now in 2 & 3 I have no compression. Should I just pull the head? There's one valve that has a 3.10mm shim, which is the biggest that Suzuki makes, and it still has .23mm clearance. I really want to get riding this bike before summer is all used up, so please help!

[Agemax]

welcome to the site. it sounds like you have some serious issues with your valves.
you say you used to have compression? what have you done to change that?
are you sure you have done the valve clearances correctly?

i think you need to pull the head and see what you have done wrong!

[Triam]

I forgot to add that it had a lubrication issue before so the cams weren't getting any oil at all. I started a thread at advrider.com. They told me to come here because you guys know everything about these bikes. This is the original thread http://advrider.com/forums/showthread.php?t=900950 it has pictures and a more detailed description of what I've done to this bike.

[Triam]

so..... I also forgot to say that to change out shims I did the zip-tie under the valves thing. I actually used some insulated wire so the valves couldn't shear the plastic off. Some say it bends the valves and that may be the case with my valves... What do you think?

welcome to the site. it sounds like you have some serious issues with your valves.
you say you used to have compression? what have you done to change that?
are you sure you have done the valve clearances correctly?

i think you need to pull the head and see what you have done wrong!

[Agemax]

only one way to find out! with oil starvation up there as well you need to strip the whole top end off

[SqDancerLynn1]

It may be the oil cooler adapter the fact that it is plugged may limit flow

[Triam]

I took that out and put the OEM hardware back in. It now works fine, the low oil flow light goes off the second I push the starter.

It may be the oil cooler adapter the fact that it is plugged may limit flow

[Steve]

... I did the zip-tie under the valves thing. I actually used some insulated wire so the valves couldn't shear the plastic off. Some say it bends the valves and that may be the case with my valves... What do you think?

Well, there is a reason that we suggest using a ZIP-TIE, not "some insulated wire". The zip-tie provides a decent cushion, your insulated wire might have done some damage. I am probably one of the biggest users of the zip-tie method. I use it on all my bikes and have shown at least a couple dozen GSers how to do it over the last few years with NO problems at all.

My guess is that you have something stuck around the valve/seat area that is holding the valve open, now you have a much thicker shim than necessary in there to take up what you believe to be excess clearance.

Before you pull the head, go back and check the valves on 2 & 3. Open the valves, blow some compressed air in there to see if you can dislodge some crud. If you still have problems, remove the carbs and exhaust system (you will have to remove them anyway if you are going to pull the head), open a valve, see if you can reach into the port with a non-scratching tool to feel around the valve to see if something is stuck there.

If that does not fix your situation, pull the head. If you end up pulling the head, it is highly-recommended that you use genuine Suzuki gaskets. Yeah, they cost more, but there is a reason for that: THEY WORK.

.

[eil]

First off, you did the right thing by joining this forum! This is _the_ authoritative source for anything to do with these bikes. Now for some random commentary from someone who's just dipping his toes in as well.

If zip ties won't bend the valves, I don't think insulated wire will. But I still prefer to use the $12 tool.

Since you took the cams out, are you _sure_ they were put back in correctly? Sudden lack of compression often indicates that the cams are off by a tooth or two. There are loads of threads about this, most people get caught up on how the links are counted. (I.e., Do you start from 0 or 1?)

[Triam]

Since you took the cams out, are you _sure_ they were put back in correctly? Sudden lack of compression often indicates that the cams are off by a tooth or two. There are loads of threads about this, most people get caught up on how the links are counted. (I.e., Do you start from 0 or 1?)

Yes. I've checked the timing. Here's some pictures so you can double check me.
This mark is to the left of the 1 4 mark

and in that position the sprocket looks like this:

as for the counting I, where the 2 is pointing is #1, not #0 and if that's the case then the 3 is pointing to #20

Did I miss anything, or is there something else I need to check?

[Triam]

Now I switched back to the shims I had before, so I once again have 5 times the clearance specified. at TDC, both valves closed, if I put an air hose with a rubber nozzle in the spark plug hole and blow I can still feel air coming out the exhaust on both cylinders. I tried blowing off the valves for crud, but the clearances are still the same they were before. Now what? Should I just pull the head?

[SqDancerLynn1]

Take a wooden dowel and whack the the valve shim lightly a few times -- re check the ckearance

[Triam]

Take a wooden dowel and whack the the valve shim lightly a few times -- re check the ckearance

I wacked it. I didn't move. What next?

[Triam]

These are my bearings.



Should I just pull the head and buy a used one off ebay to replace this one?

[ozman]

yup that bearings shot better, head to evilbay

ozman