Compression testing ?

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buzzkill

buzzkill

Mad?scientist
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So who here test there compression ? got any numbers to compare ? , I just got a replacement for my tester I lost somewhere ? so gonna check my ESP ported engine vs a Redcat I got from REP732 just for fun.
I know that testing compression is a good way to tell if you need to re-ring a engine or if you burnt it up ! lol . we used it all the time to track when to rebuild a Kart motor.
 
My gauge is my hand and foot. If I can pull without having to step on a tire, it's time for a ring.... How often would you re-ring your gokarts? Once a yr or more?
 
MonsterAir said:
My gauge is my hand and foot. If I can pull without having to step on a tire, it's time for a ring.... How often would you re-ring your gokarts? Once a yr or more?
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same here BUT I just tested the ESP motor and it was 70 PSI !!! added some oil and it went up to 85 psi throttle open so I must have leaned it out to much ?? gonna pull the top and check it later. I also tested the Redcat motor and it was 75 PSI

We would re-ring a cart motor every 5-6 race weekends depending on compression ratio.
 
What ratio are you looking for in the ESP, I never looked into those numbers before..... Just threw away my gauge too. Never used it once lol.
 
Im going to say since these are smaller engines and less air is being compressed im sure it won't be at the usual 110-120 psi range. I could be wrong but who knows
 
Well I talked to Doug over at ESP and using a automotive compression tester does not work very well on these small engines !! he say that is because the hose has about 1/2 of the capacity of the cylinder ! Never thought about that , he said on a brand new build with a Auto comp. tester he sees about 90 PSI ! FYI , Im gonna try it with a short metal tube adapter and see what I get .
Rep732 said:
Im going to say since these are smaller engines and less air is being compressed im sure it won't be at the usual 110-120 psi range. I could be wrong but who knows
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the Kart engines were 100 cc FYI , this was an Italian Race kart motor ( cant remember the make ) but it was a good motor !
 
Seandonato73 said:
You need to use a tester with the check valve at the tip of the hose. And typically 90psi would be my service limit.
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NOW U tell ME !! , I might cut the hose down and use a coupler to see if it changes , the motor runs GREAT so Im not really worried about it after talking to Doug, I might still pull the top end to inspect it anyhow.
 
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