Clutch pro I just purchased a 2002 atk 450 mx I took it out on my first ride and noticed that the clutch would slip and the catch off and on but mostly under full throttle i opened the clutch case and took a look all the clutch is brand new but i think the guy i got it from may have put 90W in the trans i know the factory recommends 80W or 85W would this be causeing the problem. I checked the cable made some adjutments and it still slipped a little. The clutch plates also seemed dry with oil on small parts im just trying to figure out what could be causeing this problem any help would be great.

Sounds like you smoked the clutch. That burnout could turn out to be very expensive!

Idle jet clogged or vacum leak clean carb MOPAR Kenny

clutch cable needs adjusting its still engaging whilst when you stop by sounds get back to me if its wrong i have other optons

From the sounds of your riding style (wheelies, etc.) you have burnt out the clutch.
No matter how much fun you think it is, Yamaha never designed them to be a toy to do wheelies. It is a sportsbike designed to go round corners fast.
The only silver lining is, hopefully the cost of replacing the clutch will stop you riding like a fool in future.

Oil is too full or scavenge pump is not pumping properly. Look down into the oil fill hole in the frame do you see oil flowing? If the oil is too full or the scavenge pump is not pumping then crankcase pressure is increased to the point where it starts blowing oil out of the vent into the airbox area... I would go with oil being too full. Drain the oil from the frame and engine and add 1 qt, perhaps a HAIR over, but not 1.5qts. 1.5qts is always too much for ours, I barely go over 1 qt. We have about 18 Dales in our group that we ride with, so we are used to seeing this.,,,

I am new to the forums and I am currently looking to buy a 2003mx 450 It is street legal with CA plates and he wants 2200 for it. When I go check it out is there anything specific that I should look for? How reliable was the motor in the 03's? I am not sure what other questions to ask. I would appreciate any help. edit: also does $2200.00 seem like a good deal for this bike? Make sure it was street registered before the cut-off date in 2004. For the rest I'd do a little bit of reading on this site on the updates needed. At $2200 it's a good deal. ,

and have done more working on the bike than riding the bike. Unfortunately I'm back in that position again of the bike not running after getting it running last fall then overheated and wouldn't start again. I think that I'm going to spend the money to have someone go through my 450 mx and rebuild and update some of the internals. Was thinking of just bringing the entire bike to someone and that way I know it would be ready to go when I picked it up. The bike is in Boise (would be pretty easy to get it to ATK), but am working in Seattle area during the week right now for a while longer. What are the options on this and who would you recommend? ,Since you are in Idaho I would recommend Blackwidow. They are a site sponser. ,,,

it revs fine but then backs down to idle slowly. Cdsracer mentioned that his cousin's in SoCal also does this.... Is it due to the different dirtbike clutch basket size? Any idears? Something simple maybe?Mine both drop right back down. Sometimes a slight hover at 2200 RPM or so then settles at 2000 RPM (usually only before motor has fully warmed up) ,,,