AAAAARRRGGGHHHH!

so if it is indeed the piston rings that are worn will the figured be the same for each test? and do you just pour oil in? About how much would you say? Tablespoons?

Yea, about a teaspoon is good. Try to have a small charger on battery as you'd like engine to spin over good. As Sandy said keep throttle wide open as you spin over engine. Let us know...

A factory shop manual or Clymers explains how to check valve clearances. We also have tutorial on our website under wg's Tech Stuff Index. I suggest you adjust valve clearances before getting too excited about low compression readings. If the valves are tight and need maintenance, this is pretty much to be expected.

Yes,what George said...check the valve clearances first,and get that dealt with,so you'll get accurate readings on the compression check.
Lets start there.

Bicycle Lee wrote:

ok... so I checked my compression and I think THIS is where the root of my problem lies. Each of the 4 cylinders has between 50-60 psi. Not NEARLY enough.
Could this be due to the engine valves? Will I just need to look into a top-end rebuild?

That's almost always the valves. Make sure the clearances are right. If it's still low, you need to pull the head.

Bicycle Lee wrote:

I picked up a simple compression tester and tested each cylinder. I was puzzled when each cylinder read basically the same, low pressure...

That is unusual, I wonder if your head gasket could be hosed?

You might want to torque the head to see if the bolts are loose.

I just pulled out all the plugs and removed the carbs and tried again. #1 was 50 psi, and the rest were 60 psi. Granted, this is testing a cold engine (since the damn thing won't start!) but I can't imagine the compression being only 1/3 of the recommended psi just cuz it's cold. Maybe I'm ASSuming....

I checked valve clearances and here's what I got by cylinder:
#1. INTAKE- .102mm
Exhaust - .102mm
#2. IN - .102mm
EX - .102mm
#3. IN - .051mm
EX - .102mm
#4. IN - .076mm
EX - .102mm

so these are all within the specs I have seen for my model/year. What now? Head gasket? Piston rings?
If not THESE, then what after that?

My engine had 80k miles on it and only showed a 30psi shift from cold to hot due to ring wear (120 to 150). Compression that low has to be either valves, head gasket, cracked head, something like that. Rings might if they broke but how could all the rings break at once? I have never seen four cylinders all drop that low and read the same. valves don't usually do that. Sounds like the head needs to come off.

I would try a second compression tester. Ed

Like Bountyhunter mentioned,check and retorque the head nuts and see if that makes a difference.
But...make sure you use a torque-wrench to do this,so you know for sure where they were at before tightening them.

Also...get this post moved to where it belongs...just noticed that it's in the "CARB" section.

yeah, when I started it I didn't know my compression was low... how do I move a topic?

One of the mods will have to do it for you,bud.