Purging Coolant like crazy and white exhaust.

[FinalImpact]

A compression test will not tell you anything as far as loosing coolant, don't waste your money. The only time I'd run a compression test on an engine is if it were skipping or otherwise running bad.

Pretty true!

That's not to say the HG will live a long healthy life as it may have cost it some life - but if you caught before it did any damage from over heating - you might just be fine! I'd play it safe and swap the fluid every 2 years if it makes through the summer!

This still cracks me up. . .

radiator cap FTW!

 

[04fizzer]

A compression test will not tell you anything as far as loosing coolant, don't waste your money. The only time I'd run a compression test on an engine is if it were skipping or otherwise running bad.

A compression test could show if the head gasket is leaking, though. If the cylinder is pressurized, and the coolant bubbles, you'll know there's a problem.

 

[GTPAddict]

If the cylinder is pressurized, and the coolant bubbles, you'll know there's a problem.

True, but that is not a compression test. When doing a compression test, a gauge or pressure transducer is screwed in to the spark plug hole and the engine is rotated. This tells you how good the rings and valves are sealing the cylinder.

When you do what you're talking about, you pressurize the cylinder. This is called a cylinder leak down test. This also requires knowing where the cam lobes are so you can verify the valves are all closed. Usually the easiest way to do this (on a car anyway) is to pull the valve cover. Not so easy on these bikes but I'm sure there are other ways of knowing.

 

[04fizzer]

True, but that is not a compression test. When doing a compression test, a gauge or pressure transducer is screwed in to the spark plug hole and the engine is rotated. This tells you how good the rings and valves are sealing the cylinder.

When you do what you're talking about, you pressurize the cylinder. This is called a cylinder leak down test. This also requires knowing where the cam lobes are so you can verify the valves are all closed. Usually the easiest way to do this (on a car anyway) is to pull the valve cover. Not so easy on these bikes but I'm sure there are other ways of knowing.

Good call. My bad.

 

[ELHOCKEY]

This tells you how good the rings and valves are sealing the cylinder.

(And head gasket)

Also will help to put my mind at ease on a cold and hot engine if the compression measures within spec on each cylinder than it goes a long way to indicate that the head gasket is sealing well between the cooling jacket and cylinders.

If there is a small leak in the HG that does not cause a significant amount of coolant to be lost it still more than likely will show a loss of compression.

 

[FinalImpact]

(And head gasket)

Also will help to put my mind at ease on a cold and hot engine if the compression measures within spec on each cylinder than it goes a long way to indicate that the head gasket is sealing well between the cooling jacket and cylinders.

If there is a small leak in the HG that does not cause a significant amount of coolant to be lost it still more than likely will show a loss of compression.

My heartache with a CT is that by the time the average mechanic gets the plugs out, the head area is no longer at operating temp so a weak gasket could go undetected.

If you had baseline numbers for all 4 cylinders from a gauge you own (think comparing apples to apples "history") this would be best. As it stands now you have no history so as long the holes meet spec - it's a go but that doesn't mean its OK.

So if i were you the money spent on a misfit mechanic could be used to buy a good quality gauge and couple of tools to do it yourself. With this, a month from now you could do it again and see if you get the same results. This will add more value than a stranger checking out you bike!

That's what I would do if it were mine. . .

 

[FinalImpact]

(And head gasket)

Also will help to put my mind at ease on a cold and hot engine if the compression measures within spec on each cylinder than it goes a long way to indicate that the head gasket is sealing well between the cooling jacket and cylinders.

If there is a small leak in the HG that does not cause a significant amount of coolant to be lost it still more than likely will show a loss of compression.

IMO this type of testing will only show when the HG is well on its way out. Because your's is running well, it may go undetected yet still have a small leak. A better test would likely be one which tests the acidic content of the coolant. Although I have heard of exhaust gas sniffers - it seems difficult to find anything other than a Canary which you'd have to train and results may vary. :don'tknow: