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dirtysouth

05 WR450 to YZ time????

4 posts in this topic

New to the Four Stroke world. So far so good. Switched from CR250 to WR450 and streeted it. Only got 500 miles and I'm liking how the power comes on all the way out. Needless to say, I want more. Have been reading about the grey wire deal and sounds easy enough. Advanced timing sounds like fun. :banghead:

My question is concerning the exhaust cam advance. Was reading some threads that said the following "You cannot simply rotate the exhaust cam to achieve YZF timing on the 2003 model. This is because of the new auto-decompression feature of the 03 bikes. Although the bike will run properly, it will not start. The 03 WRF exhaust cam lobe is the same as the 03 YZF. The auto-decompression nipple is in the same position. The timing mark is one tooth different, same as in 01 and 02. Even with that said, you CANNOT move the WRF cam one tooth to simulate YZF timing on the 03. The difference in the two cams is that the nipple on the WRF cam sticks out about 1mm more than the YZF and therefore opens the exhaust valve too far when adjusted to YZF timing. To obtain YZF timing on the 2003 WRF you must purchase and install the YZF exhaust cam."

Does anyone know if this is also true for the 05 WR450 or can I just advance the timing using the factory exhaust cam?

Lookin to learn.... :applause:

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no, you have to buy a YZ exhaust cam. you wont miss the old wr one..............

More than not-I'm assuming the '04 would require the purchase of the YZ cam as well?

Thanks

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The only way you can re-time the late model WR cams is to press the sprocket off and move it to the YZ position and press it back on. I'm kinda leery of the procedure, as I would have to tack weld the sprocket in place for peace of mind once I got it right. Knowing my mechanical skills.....I'd have to press it off and on a couple of times to get the timing just right.

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