01 YZ426 stock carb and plug cap change

I just got a 01 YZ426 and was just wondering if anyone knew what MM the stock carb was and was wondering if anybody had a rough guess of the jetting I will need to perform because I just ordered a FMF mid pipe and slip on Titanium. Also my plug cap went bad and have to install a new one and was wondering if that cap just unscrews from the wire. Thanks for any help guys you truely seem to be experts.

I'm not sure about the jetting. But, I do know the plug wire simply pulls off. It's pretty hard to get off sometimes.

I just got a 01 YZ426 and was just wondering if anyone knew what MM the stock carb was and was wondering if anybody had a rough guess of the jetting I will need to perform because I just ordered a FMF mid pipe and slip on Titanium.

Unlike some older thumpers and most 2 strokes, most modern MX 4-strokes won't need much jetting adjustment w/ the addition of your avg. aftermarket exhaust (provided the jetting was ballpark to begin w/).

You alter a lot more about the breathing characteristics of a two stroke by changing the expansion chamber shape, and a four stroke will need re-jetting if the breathing characteristics are altered greatly, like going from a WR or XR stock system to a closed-course competition system.

Bottom line is if the bike is jetted properly you'll likely only need a fuel screw adjustment.

Hope this helps.

Oh, forgot, your carb is a 39mm Keihin FCR. Stock jetting is 42 pilot, 162 main, EJP needle on 3rd clip, fuel screw at 1.75 turns out.

Pretty sure that is it, anyway....

your the f%ckin man thanks a lot. guess it would be nice if I had the manual but a clymer is on it's way!

you should do the coil on cap mod. It is clean , works and makes the carb and shock easier to get to (after you remove the old coil)

From user "Mike Dean"

"I sell a coil on plug kit, includes everything you need including a new coil, wiring, connecter, shrink tubing, convolute tubing, and simple instructions. $45

Mike Dean

www.mikedean426@excite.com

608-576-8745

(notice the coil is removed from the frame.....)

64735f96.jpg

Anybody know if these kits are still available? Where can I get one? I can find the coils just not the plug. Thanks!

GM sells replacement connectors and terminals for their stuff, and the connectors on Yamahas look similar to those used in Japanese cars. You might be able to match something up at a dealer.

A lot of people used to use the over plug coils from a Suzuki Haybusa, and I believe that the connector was available as a repair part. Do some searching here. You should be able to find something.

Thanks gray! I will be looking!

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