How much compression does your average three wheeler need to run? Some people say at least 100 psi but one of my atc 90 had 70 and ran good.
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Arm chair racerNew to the board
How much compression does your average three wheeler need to run? Some people say at least 100 psi but one of my atc 90 had 70 and ran good.
Own-Honda 250es, Kawasaki kx60, Yamaha 350 warrior
Owned-one honda 350x three honda 90 s, one honda 110, one honda 185 , three honda 200e s, two honda 200s, one honda 200es, one yamaha 60, four yamaha 125 s, one yamaha 200, one yamaha 225dx , and two kawasaki 160 s, all of wich were good runing three wheelers. Also had lots of parts bikes. Also had lots of dirtbikes, 4 wheelers, gokarts, mopeds, and snowmobiles.
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Arm chair racerThe day begins with 3WW
Originally Posted by jawalth6
Hello
How much compression does your average three wheeler need to run? Some people say at least 100 psi
Why do you want to know?
It’s around 105 psi
xxxxx
one of my atc 90 had 70 and ran good.
Absolutely impossible the math/physics simply does not allow it therefore either your gauge was inaccurate, incorrect for the test [needs to have a short small id hose] and/or improperly done. This would calculate to a static compression ratio of approximately 5.0 using an intake valve closing time of 50 degrees abdc.
xxxxx
Hope this info helps
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Arm chair racerThe day begins with 3WW
Hello
It could run on less depending but it won't run even close to "good" as you claim.
Power User
4 Wheels? Huh?
The factory spec is different for each machine..the 200cc Honda is 156+-14psi, the 110cc is 177+-psi.
Those who suggest that significantly lower numbers are fine are only fooling themselves or wanting to avoid the repair.
True an engine will run at a considerably lower compression but run well is another story. If the numbers are even 30-40psi below spec a whole list of issues can result from smoking, to difficulty starting or getting a regular idle. Also a very sharp decline in power..
One old school method to gauge how much compression is lost due to ring wear is simple. Use your compression gauge and get your engine compression, then shoot a small amount of oil into the cylinder and slowly turn the engine over a few times. Then repeat the compression test..a sudden jump on the second test, say 20-30 pounds is a definitely a problem.
An ATC90 running on 70PSI..I say is impossible! I'd sure want to see the numbers on a properly calibrated compression gauge to believe that! Until then I say it's fiction...
Last edited by dougspcs; 04-30-2013 at 01:51 PM.
Current toys..
1986 Honda 350X..trail bomb!
1985 Honda 250SX..my main mudder
1985 Honda 250ES..Back in Black Trike
Current non-trike toys:
1990 Honda TRX300FW
1995 Seadoo GTX
1998 Polaris Indy Lite 340(Nearly new looking)
1998 Polaris Touring 500
1998 Club Car (electric)
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Arm chair racerNew to the board
My gauge must be ruined. It was a 20 dollar Harbor freight one.
Own-Honda 250es, Kawasaki kx60, Yamaha 350 warrior
Owned-one honda 350x three honda 90 s, one honda 110, one honda 185 , three honda 200e s, two honda 200s, one honda 200es, one yamaha 60, four yamaha 125 s, one yamaha 200, one yamaha 225dx , and two kawasaki 160 s, all of wich were good runing three wheelers. Also had lots of parts bikes. Also had lots of dirtbikes, 4 wheelers, gokarts, mopeds, and snowmobiles.
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