YFZ450 Major vibration problems, help!

[yfz513]

hi there, ive been reading many many forums on here for a long time to help with problems ive had in the past, but havent seen one to help with this yet. Ive built a 2004 yfz 450 with the athena 480 kit, hot rods stroker crank, hot cams, ported and polished head, and im not too happy with the results. It idles fine, revs fine, reaches the rev limiter fine, but once its in the high rpm's for more than 30 seconds or so it seems to starve for gas, i figured on a delivery problem, changed to a hi-flow petcock, didnt help. I installed a dial-a-jet at this point on my edlebrock carb. This smoothed out any flat spots i had but didnt solve the fuel problem. This is one thing im worried about, along with vibration. That is my main concern. Right from idle all the way through the rpm's, all the time it vibrates terribly, i relize it will vibrate a little more with a stroker but this is awful. Ive taken the side case off, checked my counterbalance, all the marks line up fine, put an indicator on the end of the crank, just under .002 runout at the very end of the crankshaft. Everything is tight. Im at a loss for answers, i hope someone can help me out.

[jjm400ex]

did you have the crank/piston/rod balanced i've heard of balance issues with hotrod cranks

[soyo]

you probly should of had it balanced with the piston. dont know much about dial a jet, but the edlebrock carb shoul go! i never had any luck with them! the stock fcr should out perform that carb. i would also look at getting it bored out to at least 42mm. it seems that its running lean if at higher rpms it "looses power" since you have that carb you can adjust for fuel with the top screw on the carb, i would try to richen it up and go ride it and keep trying. but i would really try the stock carb. as for the vibration theres not much you can do at this point unless you take it out and get it balanced. many stock yfz's vibrate like crazy anyway. with the hotrod cranks you need to balance because of this reason. the trx's aren't that bad if not balanced though! hope this helps and keep us posted.

[yfz513]

with less than .002 runout is it still worth taking it out and having it balanced? i have no problem doing that, the season is almost over anyhow, i just dont want to be wasting my time.