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milton450

Hi, I'm new, can you help?

9 posts in this topic

Hi, I'm new to WR450s and just wanted to know if someone could give me a little background on them.

1) Could you give me the years of production for each? (400, 426,450)

2) What are the main differences between WR motors and YZ motors?

3) Did YZ (4 stroke) motors come before WR motors, or did they both hit the market the same years?

Thanks guys, I'll be here a lot! :)

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I'll try...

1) Could you give me the years of production for each? (400, 426,450)

400's 1998-2000

426's 2001-2002

450's 2003-

2) What are the main differences between WR motors and YZ motors?

The main differences are NOT in the motors. Those are BASICALLY the same. The differences come in the "extras".

YZ's are made for the tracks, so they don't have the need for things that the off-road WR needs: Lighting (stator), tail light, kick stand, over-flow bottle, and gearing change. The WR stands for Wide Ratio. Couple of gears in the tranny are different.

Inside of the engine there is a timing difference. Old-school bikes can be switched around with no liablilities. Take off the valve cover, loosen the cam chain, and turn that exhaust cam back a tooth, and you can get YZ timing out of your WR. Some are even getting the new '03 cams (they have auto decomp built in!) and really making some serious changes!

3) Did YZ (4 stroke) motors come before WR motors, or did they both hit the market the same years?

1998 was the year that Yamaha brought the 4-stroke motor to the tracks, and they brought it competetively! Doug Henry on that white 4-stroke was something that looked odd then, but is rapidly becomming the standard.

See you around!

B

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Welcome to thumpertalk. You will learn alot from these guys, as I have.

Ditto what Beef said.

The 2003 WR450 has an electric start which is way cool. The big thing about these bikes, in my opinion, is that they handle real well. :):D

Ted

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Great, thanks guys, you really answered my questions! :)

Oh, one more question though. I heard the exhaust cam on the WR is different, but why would people buy the YZ exhaust cam if all they have to do is change the timing?

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Milton,

For the pre '03 bikes, the cams are the same, you just YZ time or WR time it.

Currently, some (me included) are buying the '03 cam, and putting it in the older bikes. I have a '98 WR400 that I had previously timed to the YZ specs. Since I wanted to keep the YZ timing, AND get the auto decompression, I bought the '03 YZ cam. (As was stated, you CANNOT just switch the '03 cams around. If you want YZ timing, you gotta get the YZ cam; if you want WR timing, you gotta get the WR cam. Can't switch them around because the decomp system will be defeated by the incremental tooth change.)

Hope that gets you where you need to be!

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WR's also are weighted heavier at the flywheel, if I'm not mistaken, to aid in less stalling at low RPM's. I actually weighted mine with 12 extra ounces for stall free technical riding. Welcome to the WR family.

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Brandon... you forgot "May contain traces of nuts"... and "objects in the mirrors are slower than you" ...otherwise, I think you have covered yourself... :) Wanna work for the TT legal team...?

David

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