2001 Yz 426 help plz?

5 replies to this topic
  • DunmireD001

Posted April 14, 2013 - 10:53 PM


I am looking at purchasing a 2001 yz426f from a friend soon... He got it new in 01 and has ridden it maybe 10 times since he has had it. The bike is in great condition overall, but the problem is that due to lack of riding (i assume) it is now having carb issues. It has good gas in it, but the bike only stays running while choked. It runs great that way, but when you release the choke it won't stay running... After research I see that carb issues aren't uncommon with this make/ model due to engineering flaws...

Now I know that this bike as well as the 450s pretty much all run a 39mm carb, but my question is that, could I just take a carb, (and throttle assembly if needed) off of say a 2006 model wr/yz 450 and put it on this bike?? Would it be possible? Practical? Would i run into Any issues doing this?
Or should I just rebuild the carb that's on this one and keep using it? If so are there any recommendations on brands to choose or just any advise in general?

I may possibly build this into a street legal supermoto later. Don't know if this would change my options or not...
Any feedback is much appreciated

  • grayracer513

Posted April 15, 2013 - 06:54 AM


...the bike only stays running while choked. It runs great that way, but when you release the choke it won't stay running...

The pilot jet has a varnish deposit at least partially blocking it.

Read: http://www.thumperta...726#post8021726

As to the carb swap from a 450, it's essentially a bolt-on, and the results are stunningly good. Use a carb from an '05 or later model. You'll need the 450 throttle cables, but your throttle tube will work. You'll also need as much of the 450 hot start assembly (cable, plunger, lever, etc.) as you can get the carb with. Use only YZ450F carbs, not WR or YFZ Quad carbs. The latter two are set up with a bunch of emissions junk that there's no reason to deal with. Very good mod if your carb is actually trashed, but you can probably save yours.

  • DunmireD001

Posted April 15, 2013 - 10:16 AM


K, thanks... I'll probly go with the rebuild first to see how that goes but if it becomes an ongoing issue I'll just update the entire setup

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  • DGXR

Posted April 15, 2013 - 10:32 AM


Like grayracer suggested, you might check/clean the pilot jet and see how the bike responds -- it's quick and easy and costs nothing, and it improves (if not outright solves) many idle problems. If you just want to rebuild it anyway that's up to you.

  • DunmireD001

Posted April 15, 2013 - 11:45 AM


Yeah I'll just keep a rebuild kit handy in case I need it... They only run like 40 bucks and they are always good to keep on hand in case something happens on a weekend ride and I wanna fix it on the spot. But I'm pretty sure one of the jets are clogged like you guys are saying... I'm thinking ittl be an easy fix

  • SteveSplaine

Posted April 15, 2013 - 12:14 PM


Yup, just a clogged jet. If its been sitting for more than a week or so it needs to be cleaned. If your running race gas its even sooner.

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