Pressure Testing Motors

A place for all your Diablo Rouge Questions or just a place to shoot the bull about those little Red Devils.
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Go Go Diablo
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Pressure Testing Motors

Post by Go Go Diablo » Sun Jul 12, 2009 8:58 pm

Hi all,

Pete and I worked on a motor today to freshen up the ignition system and crank shaft seals. Pete tells me that he heard motors can be pressure tested by pumping air with a small hand pump (like ones used to pump up shocks and things) and that they should hold air. I've not hear that before.

So the Hirth 54R we were working on needed seals. It did not hold any air prior. We replaced the seals and put a very slight amount of Permatex on the seal housing gaskets. Then with a good blank plate over the exhaust and intake ports, we pumped air into the pulse fitting on the engine housing.

Wow - it did hold air. We pumped in a couple of pounds and it held right there. Has anyone heard of this test before and if so, what can be expected for holding air pressure? Seems like a good test to be sure you don't have a motor with a leaky crank which tends to burn up your pistons.

Regarding the blank covers, we have them available for sale if anyone is interested. Good for testing as stated above and also for storing a motor. $3 each. Also available now are the rectangle plates that bolt on the upper side of the muffler to chassis bolts for $2 each.
Too many Diablos and parts to count.
Yamaha 600 SX

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