the pains of nooberty

[BassCliff]

Hi,

I suggest getting to the auto parts store and picking up a metric feeler gauge. After all, these are metric bikes. Most metric feeler gauge sets go down to only .04mm but that's OK. Since the spec is .03mm - .08mm, if the .04mm doesn't fit, I replace the shim with the next smaller size. Read all about it in the valve adjust guide on my website.

If a motor hasn't been run for a while, sometimes the rings will stick. If you adjust the valves, clean the carbs, etc, then just run it a little aggressively for a little while, the rings will probably re-seat and compression numbers will come back up. Keep us informed.

Thank you for your indulgence,

BassCliff

[Flaming Chainsaws]

Ah, yes. Another GS owner from Seattle . To start things off, I bought my GS450 in May 2010. It was my very first motorcycle, I have never worked on one, and I didn't really know much about mechanics. The bike had lots of missing parts and things weren't adjusted correctly. Not to mention it didn't run.

But with all the help I got from this forum, the bike runs great and is back on the road!

Maybe we can help each other out? Send me a PM if you wish.

Welcome to The GS Resources .

[thehorseman1955]

first thing is squirt a teaspoon of oil in all cylinders.if bike sat long enough to corrode top end cylinders are probably dry.if compression stays low you have maladjusted/bad valves.if it comes up then rings were dry or bad/stuck.you cant spin it fast enough by hand to check compression.also take out all spark plugs so engine spins up easy when testing.like someone else says you can run them a little to reseat rings but you can also diagnose 90% of trouble by proper testing

[rustybronco]

<snip> but now that I've done it I can only get a reading on one and it's below 50 psi. According to the PO only two cylinders had low readings. Am I using the tool wrong? I have the plugs out, the throttle open, and I am cranking the engine by hand. There is oil in the engine and I have not cleaned the carbs yet.
Also, I left the valve cover off for a few days and there appears to be some corrosion on the cams, though it mostly rubs off when I turn the engine. Is this bad? should I have been keeping the oiled or keeping the cover on? I had the bike in the garage under a tarp..
Sorry this is so many questions at once.

Cranking the engine by hand? as in not using the starter? that's not going to work!

don't worry about the rust on the cams. wipe it off, put some engine oil on the lobes and it will be just fine.

[Adler]

I suspect the tool he was referring to was a leak-down tester. Fortunately for you, its not at all necessary, adjust the valves and get the engine running and usually the compression will come back up.

Edit: what's the mileage on the bike??

Other tools you will need:
impact driver - $15
hammer - $3
beer fridge - you probably already have one.
beer - you probably already have one.

[DanTheMan]

Hey, Mr. crapidriver (hope that gets better), welcome to the forum. We 850 owners have to stick together. I don't remember if you said yours was an "L" or not, but we all know the "L" stands for Luxury and many other great things. However, my L rubbed up against a parts "G" I bought and some stuff from the G rubbed off on it , so now it's an '80 GS850GLTg.
We all have fun here, remember on the valve shims, more clearance is mo' bettah'!

[Suzuki_Don]

I'm not sure if this has been covered yet, but make sure the valves are not tight. If they are tight (not enough clearance) then you will have compression problems. The best way to check this without feeler gauges is to rotate the motor by hand until each cylinder in turn is in a position where the cam lobe is pointing away from the shim. In this position the shim should be able to be rotated. This at least tells you that there is some clearance on that valve. Which is a good place to start.

[thehorseman1955]

also get a torque wrench,,for guys not experienced with aluminum(and even the rest of us),they will save you much grief..nothing like helicoiling a few threads to give you a new perspective