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oddball

valve maintenance

8 posts in this topic

Hello,

New 02 WR426 with 100 miles on it. I have recently pulled the air box lid off and spark arrestor, cut the grey wire and did the BK mod. I have jetting parts on order.

My question is on valve adjustment. The manual says to adjust valves after break in, and the local shop says wait a season. Can I simply check the valve clearance with a feeler gauge, and if so what specs?

Better to be looking at it than for it.

Jason :)

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I checked mine at about 500 miles and they were fine. I went another couple thousand miles before checking them again.

My bike stranded me one day, would not start (and ran very rough when cold). These symptoms occurred very suddenly and I thought it was maybe just a fouled plug, but a fresh plug did not help. When I got it home I found one of my intakes had gone way tight (the others were all still in spec). I adjusted all the intakes because even the two that were still in spec were on the tight side. Exhaust were all middle of specs.

It's so easy to check them. Do it yourself. All you need is a set of feeler guages. The middle intake requires a narrow blade, but you can just cut a standard sized blade down to fit (the ones you need are like paper thin).

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let me ask you oddball did the grey wire help at all??? Also I am good friends with my local dealers mechanic and he told me that the dealer trys to get you in after the ten hour break in and get you to spend $500.0 dollars on the the ten hour tune up, He told me that he never has to adjust the valves and that it is a waste of money to bring it in. Besides you can check them your self very easy.

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let me ask you oddball did the grey wire help at all??? Also I am good friends with my local dealers mechanic and he told me that the dealer trys to get you in after the ten hour break in and get you to spend $500.0 dollars on the the ten hour tune up, He told me that he never has to adjust the valves and that it is a waste of money to bring it in. Besides you can check them your self very easy.

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*Note slight correction; (0.10 and not .010mm)

I checked my valve lash at first 1000 miles on my 2002 Canadian(no grey wire) WR426F. The "Owner's Service Manual" that comes with bike does specify 0.10 mm to 0.15 mm (0.0039-0.0059 inch) for the intake and 0.20 mm to 0.25 mm (0.0079-0.0098 inch) for the exhaust valves. My intakes were at 0.12, 0.11 and 0.12mm. Exhausts were at 0.21 and 0.22mm.

[ July 19, 2002: Message edited by: dominator426 ]

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Thanks for the specs. My valve are out of adjustment at just 100 miles. I will take care of this when I make the YZ timing mod.

As for the question for the grey wire difference, yes. I was going to put a Jerry rig switch on my bike with the grey wire, but between the BK mod and the grey wire; hang on to your bike. The bike has WR timing and I felt like it pulled hard even at the top, compared to the performance before.

Now I'm concerned about the loss of low end power with the YZ timing. Would any one give me a yeah or neah.

02 WR426

Jets and needle on order

Air box open

Spark arrestor off

Bk mod

Grey wire cut :)

not sure of WR or YZ timing

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Oddball,

Are your valves loose or tight? Cause they do get tighter with miles, from what I gather...If your gap is a bit big, you should be fine for a while. Adjustment shims come in 0.05mm (0.0020 inch) increments. Please check my correction for the proper lash readings in previous post...(0.10mm and not .010mm) Are you using a metric feeler gauge?

[ July 19, 2002: Message edited by: dominator426 ]

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Thanks for the correction. I can now see were you got your specs out of the owners manual under valve clearance. They are a little above specs, but I will put some more miles on the bike and see if it begins to tighten up. Gues I should have written down my as found specs when I had the cover off, oh well.

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