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Terrain Rider 4z

Help Gray!!!

10 posts in this topic

I got my 01 426 back yesterday from the shop. If you recall, I went with a Hotcams ex cam and the full 2000 426 stainless valve setup. Now my bike is making a lot more valve noise than it use to. Should I be running the valves in 2000 spec clearance? Or 2001 spec clearance?

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The valve specs are the cam grinder's call when using aftermarket cams, but it should be stock specs for an '01-'02, as I recall. It would not surprise me to find that even at the '01 settings, the aftermarket cam would be noisier, because the aftermarket grinders don't always put as much effort into the quieting ramp on the leading edge of the lobe.

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The valve specs are the cam grinder's call when using aftermarket cams, but it should be stock specs for an '01-'02, as I recall. It would not surprise me to find that even at the '01 settings, the aftermarket cam would be noisier, because the aftermarket grinders don't always put as much effort into the quieting ramp on the leading edge of the lobe.

If he's going for the 00 (stainless) specs, then shouldn't the ex valves be at 0.25-0.30mm vice the 01-02 spec of 0.20-0.25mm?

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Here's my two cents.... I have a 2000 YZ426 and removed the old cam and replaced it with the HOT CAM. I used the factory specs and the motor was making a ticking sound, so I checked the clearance again and agian. The problem was they were within the specs so I left it alone and got used to the ticking sound 3 years ago. The bike still runs great after being abused in the sand and tight woods trails. I think the sound you might be hering is the decompresion arm in the front of the sproket, every rotation it will make a clicking sound... Like I said this is my two cents with my experince....Good Luck...

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I think the sound you might be hering is the decompresion arm in the front of the sproket, every rotation it will make a clicking sound...
The Flyweight should not make any noise at all at any speed above 600 rpm, which is well below idle.

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Ryan, when I put the Hotcams exhaust cam in my '02 I noticed a little more noise also, finally just got used to it and have never had a problem.

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The Hot Cams , even when shimmed perfectly will be noiser. As Gray pointed out, the lobe ramps are steeper and the valve action is a tad more abrupt, this leads to more noise.

The HotCams rec. clearance should be used as it is a good comprimise between the valves slamming shut and the action being as gentle as it can be, given the cam profile.

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Wow that is a bad noise then. My bike is also a PIA to start now when cold, but that could be the cold temps here in eastern WA? I can't ever remember having such a hard time starting, even in the winter.

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