To much compresion,any ideas why?

**YTZ250#1** · 02-09-2004, 12:06 AM

A friend of mine has an 84 big red.He had a bore job done and installed a new piston and rings,also a new cam.It starts and runs,but is pushing
270# of compresion.His book says it should be around 165.2 gages had the same reading so that rules out a bad one.he is affraid that if he runs it to much that it will blow appart.Any ideas what could cause this thing to be so high on compresion?

**250R4Ever** · 02-09-2004, 12:17 AM

your friend must be reading the wrong number or something because if it had 270lbs of compression you wouldn't be able to start it with the pull rope. i know a mechanic around here that has a 85 tecate 3 and his had 201lbs of compression at the plug and he has broken kick starters left and right, so you must be reading the numbers wrong or you're not testing it right or something.

**KASEY** · 02-09-2004, 12:25 AM

i run 225 psi in my 250r and thats alot!!! so something is really wrong!!!! either your guage is wrong ,, i don't think even arnold could pull start that!!!!! better check it again,,,,

**TRI-Zbrian** · 02-09-2004, 12:32 AM

lol OMG that thing would rip your arm off trying to pull start it

**250R4Ever** · 02-09-2004, 12:37 AM

Originally Posted by KASEY

i run 225 psi in my 250r and thats alot!!! so something is really wrong!!!! either your guage is wrong ,, i don't think even arnold could pull start that!!!!! better check it again,,,,

or arnold would be picking up the whole trike by the pull rope while trying to start it. lol

**YTZ250#1** · 02-09-2004, 12:40 AM

It has electric start so I don't think he is pulling it.And he has had 2 gages on it,they both read 270#.he is very mechanicly inclined and is reading the gage right.Any other Ideas?

**slippy4** · 02-09-2004, 01:05 AM

with that much compression i dont think regular pump gas would run right in it. is it warm when he tests it?

**250R4Ever** · 02-09-2004, 01:08 AM

i don't think an atv starter can turn over that much compression

**mudduck14843** · 02-09-2004, 10:01 AM

did he put in a high dome piston?
my 200x pegged a 200psi meter but i have a high comp piston.
i would run airplane fuel or race fuel in it and run her.

**ATCMedic** · 02-09-2004, 01:52 PM

You mention it just had a bore job done, did the machine shop deck the cylinder or mill the head? That would raise the compression ratio...

**Dan Tenn** · 02-09-2004, 02:41 PM

Are you doing the compresion test with the throttle wide open, and pulling it over a few times ?

**YTZ250#1** · 02-23-2004, 11:22 PM

Here is what we found out.It is bored .80 because the shop messed up the first time and had to rebore it.They also ordered the piston as the replacement for the one that got messed up in the bad bore.They ordered
a 12.1 piston,and it is supposed to be 7or8.1.Any body know where we can find a low comp piston?All the books I have only list the 12.1.

**TRI-Zbrian** · 02-23-2004, 11:40 PM

try dennis kirk

www.denniskirk.com

**rob0781** · 02-24-2004, 02:05 AM

Originally Posted by mudduck14843

did he put in a high dome piston?
my 200x pegged a 200psi meter but i have a high comp piston.
i would run airplane fuel or race fuel in it and run her.

1984 big red almost mint STOLEN BY: EJ'S TOWING AND REPAIR IN HORNELL, NEW YORK(LEGALLY)!!!

How do you legally steal a trike???

**mudduck14843** · 02-24-2004, 10:06 AM

[quote="rob0781"][quote="

How do you legally steal a trike???[/quote]

it was towed and he wouldn't let me have it back for a couple weeks then when he finally released it the storage/tow bill was outragous

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To much compresion,any ideas why?

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