Blown Top end

[Joe400ex]

HEy whats going on guys. I recently got a 2 400ex engines from my manger, hey bought 2 motors from the dealer for his sons 400 when he raced and sent the motors to TMM and got one of them bored to a 416 with a port and polish, hot cams, hinson clutch basket barnett plates he told me that the motor only has 3 hrs on it and he blew the top end. The other motor i think has the same set up but stroked. He said he has 3 hours and he blew a rod. So i was wondering what could be the cause of these problems. and what do u think it cost to reapair the motors.

JOe400ex, thanx

[Joe400ex]

cmon guys

[PismoLocal]

If he blew 2 400ex motors within 3 hours of run time on each it sounds like the problem is the mechanic who did the motor work. :D


There could be multiple things wrong with each motor your going to have to inspect each one carefully and replace every part that has damage. Assuming all you need in the first motor is a piston kit and a hone your probably looking at any where from $100-$175. On the second your probably going to need a new rod, piston kit, maybe a whole new crank or a rebuilt one depending on how much metal is floating around. No one will be able to give you an accurate estimate because usually when some thing breaks it damages other parts as well.

If you dont feel like fixing either one of the blown motors let me know. I'm looking for a transmission. I don't need the motor to work because all I need out of it is the tranny.

[79400ex]

Is it just the head gasket or the piston or valves? It makes a big difference. Because each one has their own causes.

[Joe400ex]

Ok the guys son raced a 1999 400ex and they bored it and stroked it . The they went to the honda dealer bought a engine and sent it to CT racing and had it all worked on. When they got it back the motor ran a half moto and blew. suposely it has a blown top end The stroked motor supposaly only has a blown rod. so thats what i know as of right now.

thanks