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View Full Version : 250R-310 piston help???



danimal95
05-27-2008, 07:02 PM
so i decided to put the 310 kit in my 85 R this weekend,after pulling the motor splitting the cases and installing the new crank and piston assembly,all is well.after sliding the new jug over the piston and rotating the assembly i notice that the piston is .030 out of the hole measured at the oter diameter ofthe piston not the dome,i figure i can work around this by machining the head no problem.then as the piston reaches the bottom of its stroke i notice that it doesnt go far enough down and is blocking 1/3 of the intake ports and 1/4 of the exhaust port..this i cant work around any thoughts?????it seems as though the piston was made wrong,i need help asap thanks

DeePa
05-27-2008, 09:33 PM
i know that 87-89 trx pistons/crank combos were different than 85 and 86

maybe you got a long rod crank?

mike

danimal95
05-27-2008, 10:11 PM
i know that 87-89 trx pistons/crank combos were different than 85 and 86

maybe you got a long rod crank?

mike

i thought that as well but the piston is only out .030 and if it were the long rod it would be out .190