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eazrider

YZ 450 Manual Decompression Assy.

5 posts in this topic

Has anyone installed a manual decomp. assy. from a 426 on a YZ 450? The 450, under normal conditions can actually be started by hand (I've done it) but sometimes, after laying it down (upside down?) the motor loads up and requires kicking until one is red in the face to get going again. With a manual de-comp capability, it is a small task to pull the lever in, hold the throttle wide open, kick it over 5-6 times to clear the extra fuel out of the cyl, and then start normally. Any thoughts?

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You can do this. It will not hurt anything. The parts off the earlier models will fit. Use 2000 YZ426 parts.

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there is actually a kit sold by Yamaha , have your local yamaha parts man look up in the micro fische for your bike . It should be towards the top named something like alternate decompresion . extremely cheap compared to buying new pieces individualy. Or find someone who just put in an auto decomp. Hot cam in their older bike and get their old parts

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there is actually a kit sold by Yamaha , have your local yamaha parts man look up in the micro fische for your bike . It should be towards the top named something like alternate decompresion . extremely cheap compared to buying new pieces individualy. Or find someone who just put in an auto decomp. Hot cam in their older bike and get their old parts
The kit is PN 5TA-W1228-00-00

Simply opening the throttle wide open and kicking it will clear out a 450 with the decomp, too. It would be a little easier to kick over, but it works without the manual decomp nevertheless. Your thoughts were mine before I actually owned my 450 for a while, since I'm an old time thumper guy, and am familiar with pretty much every trick you can use a decomp lever for. Now, I really don't miss it.

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Like greyracer said, just kick through it a 10-15 times then it should fire right up. I wouldn't bother with the manual decomp. I had serious doubts about removing my decomp lever when I 450 cammed my bike, but now I have no regrets.

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