[got_rice111]

Hey guys,

I need to do a compression test on a ex500.

I know that i need a pressure gauge, but do i need some sort of adapter to attach the gauge to the sparkplugs?

Also, whats the best way to get to the spark plugs on the ex500?

And do any of you know what the compression value of a decent ex500 engine should be?

Thanks

 

[fog]

Hey guys,

I need to do a compression test on a ex500.

I know that i need a pressure gauge, but do i need some sort of adapter to attach the gauge to the sparkplugs?


Your compression tester should screw into the plug hole directly.



Also, whats the best way to get to the spark plugs on the ex500?

If you mean to get them Out you need an 18mm thin wall socket. and remove the tank.


And do any of you know what the compression value of a decent ex500 engine should be?

Start at 16 psi m/l times the compression ratio of 10.8 to 1 + the one starting atmosphere 16 = 188.8 PSI in a perfect world. Anything around 160/170 is good.

On a warm just run engine remove both plugs block the throttles wide open and crank till the gage will go no higher.

FOG

Thanks

 

[knightslugger]

they do sell compression kits at your local auto parts store. Sometimes you'll be able to rent them as well. all should come with instructions.

 

[dragknee]

you can make one too fairly easily. google for instructions

 

[dad]

Make SURE you open the throttle all of the way while cranking. It's in the instructions but many times folks don't do it and many an engine has been torn down for no reason. You WILL get terrible readings if you don't.

This is standard practice doing a compression test but is MOST critical on any engine that has individual intake runners and butterflies. On many cars with a large common manifold the check won't be proper but won't be so grossly whacked out cylinder to cylinder because they all draw from the same common manifold, therefore get a reasonably uniform fill on the intake stroke. The readings may be lower than actual but not erratic from cylinder to cylinder, unless one has a problem. That's why on a common manifold engine the check might still be useful and not give wildly erratic readings unless there's trouble. Not so on the individual intake engines like bikes. A subtle difference in carb sync will give a wildly erratic reading.