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underground-mpyre

Installing a '07 WR450 carb on a 426, what to do?

45 posts in this topic

Installing a '07 Wr450 carb on my Wr426, I know I should turn out the full screw two full turns, what else like needle or anything I need to do before installing?

 

Plus, also going to install the auto-decomp Hotcam too while in the process. With the decomp cable going to be useless and of course disconnected, can I run the Hot-start cable to the now-useless decomp lever or do I need the WR450 hot-start lever? I am asking if the 426 decomp cable lever and the wr450 hot-start cable lever compatible?

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You will need the hot start lever and cable

Copy the jetting from you YZ carb

Block off the ACV valve on the side of the carb by removing the plastic piston and putting a full gasket under the cover

Be sure to lightly coat the hot start plunger in Anti-sieze

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You will need the hot start lever and cable

Copy the jetting from you YZ carb

Block off the ACV valve on the side of the carb by removing the plastic piston and putting a full gasket under the cover

Be sure to lightly coat the hot start plunger in Anti-sieze

I do not have a Yz carb, but a '07 WR450 carb. Do I need to raise or lower the jet needle?

 

i got the Wr450 cable for the Hot-start and would like to use it for easy trail starts. Getting a hot-start lever is no problem, but wondering if the 426 decomp lever was compatible.

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Somehow there is a miscommunication: I own a 2002 Wr426 and updating it with a '07 Wr450 carb and asking what is there to do to prep the carb to the 426 before I install it.

 

Sorry, I am trying to be as clear as possible on what I asking.

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Somehow there is a miscommunication: I own a 2002 Wr426 and updating it with a '07 Wr450 carb and asking what is there to do to prep the carb to the 426 before I install it.

 

Sorry, I am trying to be as clear as possible on what I asking.

 

Right, and your 2002 WR carb IS a YZ carb: no ACV port

Copy the jet sizes from your oldest carb, but use new parts.

Service the new carb with fresh rubber parts

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You do not adjust the fuel screw by turns, you adjust it by idle speed. start with 1 turn out, adjust idle low as possible (hot motor) then raise it with FUEL SCREW. 

If it goes to high, lower it with idle screw.

 

Your accelerator pump should be re-built to 2008 specs

 

Read this

 

http://www.thumpertalk.com/topic/1093495-fuel-screw-and-jetting/

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Right, and your 2002 WR carb IS a YZ carb: no ACV port

Copy the jet sizes from your oldest carb, but use new parts.

Service the new carb with fresh rubber parts

Where can I find the right sizes at what website?

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That is all I need to replace is the spring in the pump?

 

How do I find a full gasket to block off the ACV valve next?

 

It does not replace the spring in the pump, it replaces the apump linkage spring, not the diaphragm spring.

 

Use rubber, cardboard, anything. Then change a 100 air jet.

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Make sure you plug the ACV well or it can be a headache. I epoxy mine shut so they look like a un drilled YZ carb.

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