300trx has me baffled!
#1
300trx has me baffled!
Just put new rings in my 300trx(has a 10:1 85mm piston) and a web 40b cam. I am running it with no base gasket for a little added oomph. Last night i got finished putting the top end back on and everything. Started it and let it idle for a few seconds, sounded great. However as soon as it gets above idle it has a really loud knock. I am at wits end. Do you think I need premium?
#2
300trx has me baffled!
I went from a 9.2:1 stock piston on my quad which is not a 300ex to a 11:1 piston and a race cam and it was recommended to run atleast 108 octane race fuel. I would definatley try a higher octane gas might not need that high but its better to have too high of octane then not enough.
#3
300trx has me baffled!
Originally posted by: gotmuddy
Just put new rings in my 300trx(has a 10:1 85mm piston) and a web 40b cam. I am running it with no base gasket for a little added oomph.
Just put new rings in my 300trx(has a 10:1 85mm piston) and a web 40b cam. I am running it with no base gasket for a little added oomph.
#4
300trx has me baffled!
Unless the timing is way off, a motor isnt gonna knock from spark unless theres a load on it. reving in nuetral, isnt a load. add some octane booster and see if it goes away, but im thinking it wont.
When the head was off, did you see how far up the piston went? Is it possible the piston nows goes too far, because the base gasket is out?
When the head was off, did you see how far up the piston went? Is it possible the piston nows goes too far, because the base gasket is out?
#5
300trx has me baffled!
i'm with hondabuster on this, i'd say that yer piston either slapping the head and might bend a ring land as a result, or you might be hitting a valve, both not good, before running the motor without that base gasket i would've done a clay-ball clearance test between the valves and the head to make sure they don't touch, with the higher compression piston the dome is probably higher and near hitting the valves anyway, so either way you cut it, take it apart, check the piston dome for marks, check the ring lands for bent sections, and check the valves to make sure you did'nt bend them, the 10:1 piston should have enough oomph, if not i'd look to swapping engines for a 400ex. but for your motor, at best, no damage, at worst, bent valves or cracked piston domes and bent ring lands. good luck...... josh....
#6
#7
300trx has me baffled!
Guys, I never said I have a 300ex. I have a 300 TRX. this is the old-school 2-valve motor. The 10:1 compression piston I run is a flat top. before I took the top end back off I checked the piston/valve clearance using a piece of solder. Besides, a 350x cam wont fit in a 300ex. Today I am gonna put the cylinder back on, check the timing, and put some octane booster in it.