yzf400 Decomp cam for the millionth time!!

I have a 1999 YZF400, what are the parts required for the cam install (where can I order them, I live in so cal) and what's involved in the installation process?

I know it's posted a million times but I cannot find all of the info on one thread?

Please help a fellow YZ rider out.....Thanks a lot. :):)

Get a HotCam http://www.hotcamsinc.com/catalog.asp#4001-1E%%Yamaha%%YZ/WR%20400/426%%1998-2002%%Exhaust%20Cam P/N 4035-1E. They run $190 retail which is close to the same for a new OEM unit with the autodecomp. The HotCam is a better way to go since the cam sprocket tooth pitch matches the cam chain pitch in the 400. The 450 uses a slightly different size cam chain and will wear out faster running on the 450 sprocket. I've had a HotCam in my 99WR400 since last May and have been very happy with it - zero problems and run it pretty hard in enduro and desert races. I've been checking the valve clearance after every race and inspecting the decompression mechanism for wear - so far so good.

You'll need to get some different shim pads with the HotCam. I had to go from a 174 to 205 on #1 and from 171 to 200 on #2 (the lash spec is also a little different at 0.20mm versus stock 0.25-0.30mm). HotCams sells the shim pads at the best prices I've seen. Kits cost about $90 and you'll be covered for quite a while. You can also just buy refills in the range that you need for $35. That works out to be about $1.17/shim. For comparison, Yamaha charges a little over $5/shim. If you're really tight on money after buying a $200 cam, you might ask the service manager at your local shop if he'll let you trade shims out (your old ones for the sizes that you need out of his kit).

As far as parts go, all you should need is the cam and two new shim pads. The catch is you won't know exactly what size shim pads you'll need until you install the cam and measure the clearance, so it's a two step deal unless you have good selection of shim pads on hand. Read up on the valve adjustment procedures on this web site which covers cam removal and installation. The four things to really pay attention to are (1) making sure you don't drop the bearing keeper down the cam chain well when you pull off the cam cap (2) use good quality engine assembly lube on the new cam's bearing faces and lobes (3) make sure you properly torque the cam caps back down and (4) use a good quality petroleum based oil (non-synthetic) during cam break-in. I think the HotCam also came with some pretty decent instructions as well.

Good luck.


Great, Thanks a lot!! I printed this one and will place my order today!!

Happy Riding!!

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