motor issues

[lt250r92]

I had my bottom end redone in my lt250 a while ago because the crank seals went and it was eating oil. ever since i got it back I have a really bad vibration and the seals blew out again i have put less then 20hrs on the bike since the rebiluld. ive checked the timming marks and they were dead on and the key wasnt broke . this is driving me nuts does anyone have any sugestions on what this minght be thanks.

[gassrx.com]

is the crank bearings loose in the case or is the any crank good,,

[lt250r92]

i havent tore the motor apart yet

[rideracelivemx7]

well based on what it sound. its your crank and its not balanced. cranks dont come from the factor balanced. they are machined and pretty much eyeballed. i mean obviously there not all out of wack but they always suggest having a crank spun before installing. but a mechanic wont do it unless you have them. but i can almost guarentee that being the problem. having it spun at your local shop i dont think will cost you more than 100 i think. but just the slightest imbalance will throw off the entire motor. and theres no vibrations that would do that besides the crank. but let me know if you get it fixed. pm me or email me for questions if youd like. rideracelivemx7@tmail.com