HELP!! 250r making loud knock

[trx450Rrider]

hey guys. my motor is making a loud knock when i start to rev it passed idle and it will rev alittle bit then just die. i dono what it is i checked the oil and there arent many metal shavings but when it happened i was riding and it just shut off. its been sitting for about 4 months and i decided to tear it down and check stuff. it wouldnt even start before but now it will start and run for about 15 to 30 seconds then it sounds like its getting no gas and shuts off. i put it in gear acouple times and i only got it to stay running once but it ended up dieing out again. im kinda thinking it is the crank going. it has a hot rod crank in it right now and i hear those arent that great. also when i took the topend off there was alot of metal shavings in the intake side and around the crank area but i figured it was from the new topend i just put on before it stopped running

[wilkin250r]

Metal shavings are never good.

I know it's always handy to have a starting point, or an idea what is wrong, but I honestly don't think that really matters in your case. It sounds like you need to pull it apart. Whether you know what's wrong, or you discover what's wrong when you're in there, your starting point is all the same, pulling it apart (or sending it to shop).

I had a knock and rev problem once, turned out the crank bearings were toast. Grab the flywheel and see if you can wiggle it back and forth. But that will only tell you your crank bearings, it won't tell you rod bearings or other problems.

[Rich250RRacer]

It's a Hot Rods, that says enough. Looks like it's time to replace the crank.

[wilkin250r]

Not all hotrods are bad cranks. I've got one in my 340

[trx450Rrider]

i guess im gonna pull it apart this week :(

[2muchquad]

For future reference,shavings in the topend or bottom end of a 2 stroke is never good,:( good luck with your findings..