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leak down test.correct way?


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i need to konw how to do a leak down test on the shee.i have a tester and all but i need to know what to block off and how much psi to put into it.also on a compression test should it be at running temp or cold?and does having the pipes on make a difference in the comprssion test?

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plug the exhaust ports, put the spark plugs in, plug the intakes with the gauge is one and the pump in the other.

Pump the engine up to 6psi and let sit for 6min. if it holds at 6psi you are good to go, if not pump it back up and start sprayin all the mating surfaces with soapy water. Dont forget the crank seals and the reed cage gaskets!!

 

I always do my compression tests cold and with the pipes on, not sure if the pipes make a difference though.

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plug the exhaust ports, put the spark plugs in, plug the intakes with the gauge is one and the pump in the other.

Pump the engine up to 6psi and let sit for 6min. if it holds at 6psi you are good to go, if not pump it back up and start sprayin all the mating surfaces with soapy water. Dont forget the crank seals and the reed cage gaskets!!

 

I always do my compression tests cold and with the pipes on, not sure if the pipes make a difference though.

i diid the compression test last night and it was reading like 35 or so without the pipes on and this does not seem right.it feels like way motr because it kickes over pretty hard and has good pop.im going to do it agiain today and double check everything.oh yeah i dont need to plug the intakes for the leakdown test?edit:just did it again and it topped out at 140, is this good?

Edited by mybadbanshee
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plug the exhaust ports, put the spark plugs in, plug the intakes with the gauge is one and the pump in the other.

Pump the engine up to 6psi and let sit for 6min. if it holds at 6psi you are good to go, if not pump it back up and start sprayin all the mating surfaces with soapy water. Dont forget the crank seals and the reed cage gaskets!!

 

I always do my compression tests cold and with the pipes on, not sure if the pipes make a difference though.

oops i read wrong, my leakdown tester plugs into a spark plug hole so how should i go about plugging the intakes?i have an idea about how to do the exhaust ports but im lost on the intakes.

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oops i read wrong, my leakdown tester plugs into a spark plug hole so how should i go about plugging the intakes?i have an idea about how to do the exhaust ports but im lost on the intakes.

Your leakdown kit didn't come with plugs for both intake and exh? Most testers I have seen you plug off one intake(guage adapter goes in other) and then cap off the exh.. If you don't have plugs for the intakes you can get something to work from the hardware store to get you by.. Last year when I was kinda making a kit I found PVC plumbing caps that worked nice..

 

Was 140 the reading you got in both cyl's for the comp check?

 

RIPPEN

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this is a home made kit that i put together and it worked great. i bought the plugs from the "ace hardware store". it takes a little effort to get them in the exhaust ports. but they'll go in with the aide of a screw driver. i don't recall the sizes, but the exhaust plugs are a little smaller than the intake plugs.

 

i forgot to add the pic. here it is.

post-10984-1178999205_thumb.jpg

Edited by cam2
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oops i read wrong, my leakdown tester plugs into a spark plug hole so how should i go about plugging the intakes?i have an idea about how to do the exhaust ports but im lost on the intakes.

 

I think the leak down tester you have is for automobiles. For testing to see the shape of they rings and cylinders. You should still be able to get it to work.

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i think you did a compression test first... when you take out your spark plug and thread the gauge in the head and kick it over your testing the static compression...

 

a leak down test you remove the pipes... plug both exhaust ports... have both spark plugs installed... have the reeds and manifold on the motor... where your carbs normally bolt up you want one plug with the pressure gauge on one side and then the other plug with the pump on the other...

 

pump the motor to 6lbs and watch it fr 6 mins... if it stays then your good if not do like the first guys said...

 

click on the RNBrad link in my sig to see the make your own leakdown tester

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yes the leakdown tester i have is for autos.it a snapon that screws right into the head.is it possible to do it this way?or am i going to have to adapt it to read from the intake port?will i get accurate readings if i use the adapter for the head?

yes, it will work fine just as long as it doesn't leak air pressure and you plug off the intake and exhaust ports. use something like the rubber plugs shown in the pic i posted earlier. all you're doing when you're doing a leak down test is to make sure that the intake, combustion, crank, and exhaust area (minus carbs and pipes) of the engine don't have any air leaks that will eventually cause coolant, air, and or transmission oil leaks to get into the areas where they shouldn't. when you do a pressure test and unfortunately if the pressure drops significantly it will let you know if you have a intake gasket leak, a crank seal leak, a head gasket leak, or a cool head o-ring leak (if you use one instead of a stock head), a base gasket leak, etc, etc.

Edited by cam2
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well the reason im doing it is that the last time i rode it was a fresh top end that we broke in perfectly, on the first "ride"i shifted into 6th and then it got real hot real quick and melted my one of pistons.we couldnt figure it out but thought it may have sucked air in somewhere and leaned it right out causing the meltdonwn.would i be correct in this assumption?

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I went to the parts store and got 4 freeze plugs, a piece of I believe 1-3/4 radiator hose. Stuck my freeze plugs in and hose clamped them in the exhaust ports. I took the other freeze plugs and drilled one hole in it and put a valve stem in it, used a little hand pump for air shocks on a motorcycle which already has a built in guage. The other hole was plugged solid also. I used 6 hose clamps also. Worked fine on mine.

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