Friends GS1000 motor toasted?

[GabrielGoes]

we are going to assess the problem asap we are a little busy now, i told him about the valves and he should check asap, a friend tom who builds kawasaki racing bikes told us this : " On a leak down test you need a leakdown tester. You screw in the adaptor into the spark plug hole just like you do on a compression tester. Then you pressurize the cylinder at about 80 lbs. You have a guage that shows how much it's leaking and where. An example is you 0 the meter then you hook it up to the hose that goes into the sparkplug hole. You have the cylinder sealed up. That is both valves are closed.Then see how much is leaking and is it going past the valves or rings. An example would be you shouldn't have over 12% leaking for a respectable motor. Alot of my race motors were 2-5% which is great. Say you see the guage showes 50 -60%. If it has that much you could hear it coming out the exhaust if the exhaust valve was leaking. If the intake was leaking you could hear it coming out of the carborator. If it was past the rings you could take out the oil dipstick cap and hear it coming from the bottom end. Tom"

seems pretty interesing have any of you ever tried this method for testing?

[gearhead13]

Leakdown tester?
My bet there are holes in the pistons.
Pods? 4-1? running real lean and never rejetted and ran real hard?

[tkent02]

Or maybe the valves need to be adjusted.

[gearhead13]

the plugs !! two of em were destroyed as in the tip/electrode whatever you wanna call it was GONE-non existant blown to smitherines. and the other two were snow white. we threw in new plugs hoping it would pass but still is no good! I believe it happened all of the sudden. We really thought it was ignition timing because it happened out of no where, its not, swapped all the parts on my 750 and it worked fine.

Two plugs destroyed, the same ones that have no compression?
Do you mean absolutely zero compression? Could be a burnt valve, but my bet is burnt piston.
Obviously running way lean and 2 and 3 run hotter than the outer two.

[GabrielGoes]

Or maybe the valves need to be adjusted.

I know lol i was just saaying the guy's leak thing was pretty interesting i've never heard of such a thing

[tkent02]

I know lol i was just saaying the guy's leak thing was pretty interesting i've never heard of such a thing

The leak down test is real, it will tell you exactly which valve needs to be adjusted. So does a feeler gauge.

[rustybronco]

I know lol i was just saaying the guy's leak thing was pretty interesting i've never heard of such a thing

http://www.vmaxoutlaw.com/tech/leakdown_tester.htm

Dual purposed mine from my compression tester and the regulator off one of my paint guns.

http://thegsresources.com/_forum/showpost.php?p=1180837&postcount=51

[Graham]

Why waist time adjusting the valves when the piston could be bad? The leak down tester will tell what the problem is. A real mechanic will find the problem before he takes your engine apart (even the valve cover). Harbor Freight has them cheap.

http://www.harborfreight.com/cylinder-leak-down-tester-94190.html

And Snap-on has them

http://buy1.snapon.com/products/diagnostics/eepv309a.asp

BTW; Valves don’t all of a sudden get out of adjustment and cause 0psi compression.

[bobthebiker88]

hence my initial statement of severe lean condition. a plug that has been in a running engine and is snow white bodes ill for the motor. I wish I'd taken pics of my friends old RD250 when he advanced his points too far, and the resulting piston lightening mod.

[tkent02]

Why waist time adjusting the valves when the piston could be bad? The leak down tester will tell what the problem is. A real mechanic will find the problem before he takes your engine apart (even the valve cover).

BTW; Valves don’t all of a sudden get out of adjustment and cause 0psi compression.

Why fix something for free when you can spend hundreds of dollars rebuilding it?
Yes, valves do get out of adjustment and cause 0 psi compression.

[hjfisk]

Try the valve adjustment, what are you out some time big deal thats what owning one of these jewels is all about. We had a GS 550 a few yrs back that we took to Loudon for bike week, as a burn bike , just to burn tires we beat that thing relentlessly for 3 days smoking tires,broke the tach cable over winding it 12k plus got the exhaust cherry red from the head to the tip of the exhaust can[aluminum yoshi can] and when the exhaust cooled the can cracked and fell off. Moral of the story is the motor on this thing took it, it still runs today. and still has compression, probably not what it should but still enough to run. meaning these old GS motors are bullet proof it takes alot to kill them.

[Graham]

Why fix something for free when you can spend hundreds of dollars rebuilding it?
Yes, valves do get out of adjustment and cause 0 psi compression.

Not all of a sudden.

[MisterCinders]

Why fix something for free when you can spend hundreds of dollars rebuilding it?
Yes, valves do get out of adjustment and cause 0 psi compression.

You would have to go past the valves (i.e., pull the valve cover) to deal anything that a leak down test might reveal. While you're in the neighborhood, give those valves some love. Tickle their naughty bits with a feeler gauge. If they are coy and won't open up for you, remove their inhibitions with a sexy new shim.

That may be all it takes to get some more sweet, sweet loving out of that bike. Valve adjustments are always worth doing.

[Harry P.]

lol, me thinks Mr Cinders is spending a little too much time in the garage

[Nessism]

Beat on it all you want once the maintenance is done and it's running correctly. These engines are bullet proof, however they are not idiot proof.

In the future, it's a good idea to do these simple checks before ruining the engine. Much simpler to repair before there is too much damage.

Quit guessing. adjust the valves and go from there.

A couple of awesome quotes here.

Valve adjustment is one of the most importing bits of engine maintenance...yet often neglected.

Another common, but very dumb thing, is running an engine with a header without rejetting the carbs. Hope both of these things were not done.