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david857

01 YZ426 stock carb and plug cap change

8 posts in this topic

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.

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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.

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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....

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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

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

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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.

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