So now I know why Zip-Ty sells fuel screws...

Recap: you'll remember I bought a YZ426 to make into a dualsport/'tard for messing around town on.

Had issues with the lighting kit, but got it sorted. Then issues with other stuff, got most of it sorted.

Bike wouldn't pull cleanly midrange. Thought I might have timing issues, or grounding issues or something... Classic rundown: air, fuel, spark. I went back and rechecked fuel today...

Freeing the carb to adjust fuel screws is nuts. Zip-ty will sell another tonight... the bike was running rich. Dropping the needle, raising the clip two notches and it runs better - there's only one more notch.

For grins, I'll try the next leaner needle and get the next two leaner jets. I'm at 16-1800 feet, running stock EKR and 162 jet. I may race this bike (on a roadrace course, not motocross, with 17" wheels) at 4200 feet, hence the leaner jets. I think I have enough range with cooler weather on this needle to get it right for winter (I'm in Phoenix).

The other thing is I've got a stock beat-up exhaust, and I probably will want to run an arrestor in there for the AZ and US land I want to go ride. That'll probably make me want to go slightly leaner, too.

Fun fun... still haven't run errand one or even really left my neighborhood on this bike. Soon.

You all realize that I'm eternally grateful to every person who's posted a mod or experience here, right?

I went with a JD Jetting kit and the JD mixture screw instead of the OEM Yamaha parts - for one thing, the oem.thumpertalk store doesn't list the needles. And I took to heart the warnings on the Zip-Ty screw.

Fuel screws in order of preference

Merge Racing Brass (from TT store or Merge)

Kouba Brass (James Dean has these)

Kienteh Stainless Steel (James Dean has these)

I got three Ride Eng screws (dont ask me why there are three of them)

Do not do their job - not adjusting - just not correct proportions of the tip area, messes the rubber ring etc. They all live in the toolbox now with the OEM screw in place. :thumbsup:

Zipty Fuel screws are the only ones that I have used for years and no problems period. IMO the problems with any of them are with the ones installing them incorrectly:excuseme: Unless the tolerances are off in the first place

ZipTy and the other alloy screws work, but because of the non-oem tip shape, you have to go down one or two sizes in pilot jet. Why buy a $20 screw and have to spend an additional $12 on jets? Also, being it is soft alloy and has a bit of a taper to it, some who twist it too hard, have had the tip break off in the carb, permently damaging the carb. They can work but the reasons not to want them are significant.

Some manufacturers do seem to be a little careless about the shape of the tip. :thumbsup: I can't cite any by name, but it's come up before.

I have two Zip-Ty's, and the only thing I found with them is that the spring they are supplied with is not strong enough to hold them in place. I use teh stock springs with mine and have no problem.

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