YZ cam upgrade.

9 replies to this topic
  • bfg50

Posted May 04, 2003 - 05:52 PM


I am wondering why my WR450 is hard to start after I put the YZ cam in it. Could it be the jetting? Or could it be related to the woodruff key problem, is it possible that it is bent just enough to throw off the timing?

  • Indy_WR450

Posted May 04, 2003 - 06:05 PM


I did mine when the engine was still hot and it started up right away. I also rode a few hundred miles on it before going back to WR cam. I did notice that it was a little easier to start with the YZ cam. I would check that you have the cam in the right position. Take the cover off and check everything again. :)

  • bfg50

Posted May 04, 2003 - 06:23 PM


I appreciate the feed back. I carefully checked the cam before I put it all back together. I actually marked the timing chain (with a magic marker) exactly where the WR cam's markings were. When I put the YZ cam in I used the same spot for the one that lines up with the top of the head (the left hand side mark). The top mark on the cam did not go in the exact same spot. That mark is 1 tooth to the right (closer to the intale cam). Does that sound right to you?

  • wr250rr

Posted May 05, 2003 - 02:28 AM


Hey Indy, why did you go back to the wr cam?

  • Indy_WR450

Posted May 05, 2003 - 11:48 AM


That sounds right as far as the mark on the cam needs to be at the top of the engine cylinder sleeve casting. I remember it looking ackward because the decompression linkage looked in a different position. I rechecked mine and counted 13 links between the marks on the 2 cam sprockets. As far as why I went back to WR cam timing. In tight woods and hill climbing the WR cam is superior for load end grunt. You lose bottom end to get the high reving mid and top ends of the YZ cam. I for one did not like the sacrifice. More power up top does not suit my terrain and since my style of riding is a lot of short shifting and lugging to control wheelspin (mud) the WR cam is better for me. If i were out west in the desert I would definitely go with the YZ cam it rips! :)

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  • bfg50

Posted May 05, 2003 - 12:26 PM


I counted 13 pins too. Well I have the woodruff fix scheduled at the dealership. I will let you know if it is bent. :)

  • wr250rr

Posted May 05, 2003 - 12:42 PM


Thats strange. When I put my 01 WR250F to yz spec, it gained low, mid, and top. Very noticable all around. I WAS going to do it to my 450. I don't think I'll mess with it now. Thanks alot :)

  • bfg50

Posted May 05, 2003 - 04:03 PM


Yea but if you get a pipe that boosts your low and mid range; the YZ cam will rule. :)

  • Indy_WR450

Posted May 05, 2003 - 04:06 PM


Yeah but if you get a good pipe on the WR the bottom end will rule by an even larger margin! Thunderrrrrrrrrrrrrr Alleyyyyyyyyyy! :)

  • bfg50

Posted May 06, 2003 - 05:01 PM


Don't cheat yourself. The WR with a YZ cam has plenty of bottom end. If you need more just change your sprockets. The YZ cam gives you all that and CRAZY REVING 2-stroke like BLAST OFF ACCELERATION!!!!!!!!!!!!!!!!!!!! :)

Don't forget. The WR cam is designed to s l o w you down. :D


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