03 WR450 Rebuild time

I just bought a 03 WR450 witha blown motor.

Gonna be replacing the crank and cam as the teeth are missing, also the starter basket is broken.

Anything I need to know about before I start ordering parts?

Upgrades?

How do the valves hold up on these machines?

Any and all advice is welcome

Thanx

jim :naughty:

dont know from experience but have HEARD that using the YZ cams would be a much better idea if you are in search of more power...

not so much the intake cam but the exhaust cam... or you could purchase a set of Hotcams or any other performance cam manufacturer..

dont know of any other tips but wouold sugges the performance cams!

good luck! :naughty:

450GN, got a kick out of your avatar! :naughty:

use a yz exhaust cam, 2004 crank, 2004 flywheel, and 2004 starter parts.

I just bought a 03 WR450 witha blown motor.

Gonna be replacing the crank and cam as the teeth are missing, also the starter basket is broken.

Anything I need to know about before I start ordering parts?

Upgrades?

How do the valves hold up on these machines?

Any and all advice is welcome

Thanx

jim :naughty:

I had my 03 WR450 rebuilt completely this winter.

Crank cam chain sprocket was hooked to the point I needed a new crank.

New bottom end bearings were needed.

Ti valves were beat up on the seat surface and I had them replaced with Kibble white SS valves , spring, and guides. Valve seats were in good shape so you can just put in new Ti valves springs and guides but they are more money. I put a Hinson inner and outer clutch basket but only really needed to replace the outside basket due to notch groves from the plates. New piston, rings and rod and have the jug honed and Nikasil recoated for the oversize piston up to 100mm in diameter.

Combustion head had some build up to clean off and the exhaust port had a thick build up and needed a lot of cleaning up and porting. Put in a new counter shaft bearing and seal at the rear drive sprocket because it gets abused compared to the rest of the transmission bearings. Check for rounded shifter forks. mine were still OK. :naughty:

Hey Indy, approximatly how many miles did your 03 have on it at the time of rebuild?

I had almost 12,000. miles and 3 valve adjustments along the way. The motor was really starting to run rough the last 1000 miles. You will feel warning signs. :naughty:

Hamfisted,

I have a 03 that I put an 04 crank into to solve the woodruff key issue. I know that this is an overkill, but did not like Yamaha's answer to the woodruff key repair (red locktight and lapping the surface). Had to buy 04 starter gears, flywheel and stator also, but if you are going to buy a crank anyway, consider the 04 option, you will have to go through the parts fish and compair parts and price out the options to make your decision. I have had 0 problems with this setup and am very happy with the results.

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