Will a 06 YZ450f carb fit 08 WR450? tps same settings?

Long story short, i have some gremlins in my o8 wr carb i just can't work out so I'm looking to purchase a used carb off ebay and start from there..I swapped carbs with my friend who has another 08 Wr450 and it ran perfect so I know it's my carb.

. I know the WRs have the air cut valve and the yz does not so this would potentially change the jetting. But since the CDI is different on both bikes and the acv is different, would the TPS be set different? I don't want to touch the tps to be on the safe side. Reason i ask is this opens my options for carbs.

It is a direct swap, and requires no changes, other than possibly some jetting.


TPS calibration should be verified regardless, and takes under 30 seconds with a multi meter. Check it with the slide at the bottom!

A service manual can be downloaded from Yamaha's website.


Jetting will probably be fine, but check it anyway.

The YZ needle is leaner, and the main is richer. 

If you run the stock pipe, you will have issues with being too rich after 1/2 throttle. You need an aftermarket pipe or a small main (160)


You will experience more deceleration popping, because there is no ACV system,  but it's not a big deal. In fact, it runs better this way.


Do yourself a favor and put on an R&D fuel screw.


There is no issue with a stock WR carb that cannot be fixed, short of a worn out bore, a cracked body or stripped screw holes.


If you have ever used 'real' carb cleaner on your WR carb, you probably melted the split-body gasket. This can be replaced


If you have not reamed the passage above the pilot jet with fishing line (which has a 90 bend in it) you will have problems.

Same with the apump system: it gets corroded and must be dissassembled and soaked/reamed.


Please know that most carbs from ebay are worn out, and that is why they are for sale.....you need to see the slide and bore to know.

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