TRX250r.org

Author Topic: compression for stock motor, jug, head, etc + CR head gasket?  (Read 1598 times)

Offline atvmxr

Just rebuild a motor, .060 over, cr head gasket.  gauge is only showing 155 psi.  It should be more like 190, right? full throttle, about 10-15 kicks.

Pretty sure the gauge is bad. another R motor only had 120 psi.  My sons 70 had 0psi, which started this whole train of me testing motors.  I guess either way that 70 needs a topend!


Maybe its because all the motors were cold, warmed up adds 20-30 psi?
Bunch of race quads that run on premix

Offline broken1

Re: compression for stock motor, jug, head, etc + CR head gasket?
« Reply #1 on: June 11, 2020, 11:41:48 AM »
I got 2 86's, one with a long rod crank & virgin 88 cylinder at 66.75 & the other with a short rod crank & 86 cylinder also at 66.75 with clean up porting. Both have ATC head gaskets & they both have just over 200psi. Sounds like it could be your gauge. With that CR shim gasket it should be up around 220psi & you will have to run race gas.
« Last Edit: June 11, 2020, 11:45:33 AM by broken1 »

Offline 2ndmoto

Re: compression for stock motor, jug, head, etc + CR head gasket?
« Reply #2 on: June 12, 2020, 12:10:00 AM »
You seat the rings by doing a few heat cycles?

 

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38