'81 Yamaha YZ465 Need advice

You might want to reconsider before buying a beast for vintage motocross. I have a 465G and a '75 YZ360B. The 360 is much easier to ride/race than the 465. Don't get me wrong I love both machines, but the 465 will keep you very busy.

They are extremely strong machines and once their setup they are fairly reliable. It will has brute strenght that is almost equal to a modern day water cooled 250cc. The flaw is they are not very nimble and aren't the most forgiving if you don't pay attention at all times.

Here is a link for a club that can answer specific question. The 490 is based on the 465. It just has a bigger jug and the suspension evolved.

http://autos.groups.yahoo.com/group/yz490/

Good Luck,

The 465 is a fine machine. Have the shock gone through and use a heavier oil as they don't have enough damping. Run the shock pre-load a bit higher than normal to tuck in the rake of the front and get it to turn better for moto. 465's had the best motor of the big Yamaha two strokes. 490's are beast of a machine and ever harder to jet properly. All big Yamaha's had pinging problem that can't be jetted out and race gas won't help it. Find a shop to reshape the head. Scott's Performance in Ca. used to perform the service, Eric Gorr may be another.