rod bearing ?

[honda400zx]

i jut got this 1989 yamaha yz 80 and when i got it it was seized,unseized it rode it around, and it seized. rod bearings, split the caces cleaned things up found a good used crank. put it together new top end rode it foe 45 min approx breaking it in and it just bogs out kicks over twice and locks up. rod bearings again, its all apart now and before i search for new rod and bearings heres the question. what would cause it to keep failing? had it rich to keep everything cool too just cant under stand. hope sombody can help me out even tho its a yam....

[Castor-426ex]

it can be the crank...or the rod itself...or a lot of other things

[phatswinn]

did u put gear oil in? sounds obvious but its something i could see me doing

[speedjunkie]

Originally posted by Castor-400ex
it can be the crank...or the rod itself...or a lot of other things

He is right, it could be any number of things. Time to have a machine shop look at all the rotating parts before you put it back together. Could it be that oil is not getting to the rod bearings?