Comp Test

[CA180]

How many pumps is recommended on a compression test for a 550?

Also verifying that the recommended valve clearances for the 550 is between .03-.08mm with a recommendation towards the larger gap.

Thank you

[rustybronco]

crank till the highest reading that it will obtain, if it reaches the proper compression ranges in about 3-4 compression strokes it usually indicates a good engine, 10-15 strokes not so good (also the readings will usually be low).

[CA180]

Cool. I got a reading of around 150psi across the board with 5-7 pumps. I think this may be skewed because of very very poor valve clearances.

[Nessism]

Cool. I got a reading of around 150psi across the board with 5-7 pumps. I think this may be skewed because of very very poor valve clearances.

With numbers like that you are not likely to have any valve sealing issues. This is not to say that you should not check the valves though if you haven't in a while - don't wait for a problem to occur.

[CA180]

Well, its a used motor that i picked up last weekend. and i wanted to double check everythhing before i dropped it in the bike. He told me that it had a problem of falling flat at 3000 rpm, so i'm trying to rule out everything possible before i have the same issue.

Oh and about the valves, i couldnt get a .038mm feeler between the cam and the shim. Thats the smallest size that i had on hand at the time, but its still pretty tight clearances.