i need some help from a WR know-it-all

i have a 98 wr400f

-uncovered airbox

-yzf exhaust pipe

-removed throttle stop...

wait a minute!!! that's not supposed to be removed!!!

I just recently investigated it, and it turns out the guy who owned the bike before me totally removed the stop... and the local dealership doesn't seem to be able to order one (or find the part # to order it.)

is it just a screw (if so, what size),

or is it a pin?

OR does anyone know where i could get one to file it down to correct size and install?

HELP!!! it doesn't run right on top-end without it.

also: don't the yzf and wr share the same carb?... if they do, what does the yzf have where the stop goes?

thanks for any help

Xrracer36

Some have removed them and and some have just cut them. Order a yz throttle stop and you should be all set. Don't forget the grey wire

yz throttle stop? do they have one... if so, where can i get the part # (the guys at the local shop don't see it on the card they look parts up on)

what grey wire?

ps. THANKS!!!!!!

You can order the stop from any Yamaha shop.

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01 WR426 Uncorked, YZ throttle stop, Grey wire cut, BK mod. Do I dare change to YZ timing. (soon)

Originally posted by xrracer36:

yz throttle stop? do they have one... if so, where can i get the part # (the guys at the local shop don't see it on the card they look parts up on)

XR, dont even bother ordering the YZ stop. I tried, gave them the "right" part #, and ended up getting the WR stop AT FULL LENGTH!

Just cut it down to 23mm, and put it back in. They wouldnt even give me back my $13, after realizing they screwed up. :)

Most of those guys are clueless!

xrracer36,

Do a search on "grey wire" and "grey wire", you end up with a great big grin.

no need for a throttle stop. 1mm later and the slide hits the roof of the carb and that won't do it any harm. they were like that for the first one hundred years.

Taffy

The only thing I have heard, is that the slide can crack when you bang that sucker open all the time. Never actually had anyone confirm that, however.

I have the WR stop if you want it. You can just cut it down, and stick it back in, if you think you really need one.

Before I cut mine, I called and talked to the(supposed)local Yamaha performance guru. He said leaving out the stop could cause problems with the TPS reading at WOT. The TPS is allowed to rotate past its normal range without the stop. This in turn can give a reading which is out of parameters and cause the ignition system to function improperly at WOT.

The way he advised me to go about cutting mine was to start with it cut to 24mm. Pull the air filter boot back so you can see the slide. Hold the throttle open and see how closethe slide is to wie open.Finish grinding the stop the rest of the way until the slide is just flush with the bore at WOT.

Sounds logical to me but not sure if its gospel, hope this helps.

Woody

Before I cut mine, I called and talked to the(supposed)local Yamaha performance guru. He said leaving out the stop could cause problems with the TPS reading at WOT. The TPS is allowed to rotate past its normal range without the stop. This in turn can give a reading which is out of parameters and cause the ignition system to function improperly at WOT.

The way he advised me to go about cutting mine was to start with it cut to 24mm. Pull the air filter boot back so you can see the slide. Hold the throttle open and see how close the slide is to wide open.Finish grinding the stop the rest of the way until the slide is just flush with the bore at WOT.

Sounds logical to me but not sure if its gospel, hope this helps.

Woody

[This message has been edited by Woody426 (edited October 02, 2001).]

now i KNOW your tuning "guru" is talking bollocks!

it's not about getting the slide flush with the top of the venturi ; it's about getting the needle up and out the way as far as possible in my opinion.

oh! and without sending the wrong ******* message to the TPS.

after all we don't want to hurt Mr TPS's feelings do we!

after all he is sensative to change.

Taffy

[This message has been edited by Taffy (edited October 02, 2001).]

Looking at the Yamaha parts CD, I don't see a separate part shown for the throttle stop. My WR doesn't have the stop at all and runs just fine.

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MX Tuner

in the parts fiche it is called a spring stop screw. it is not clear (at all). i will post the part number again i have it at home. that is the YZ part number. i do not rember that other post that i put it in.

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wr42601

not yz timmed yet

some mods

Easy.....I do agree with you Taffy that the farther the needle is out the better. But I also think there could be some validity to the TPS staying in check. After all it does supply the CDI with the input(along with the engine RPM) it needs produce a proper ignition curve at any given RPM and throttle opening. There is a proper resistance check in the service manual for the TPS at wide open throttle and at idle. The guru in question said it could cause a problem, not that it would always cause a problem. Just because I did mine this way does not mean I'm right.

:) Why do I feel like the bombs are about to start exploding around me....

Woody

[This message has been edited by Woody426 (edited October 02, 2001).]

Let me point out the obvious...

If you're concerned about the TPS going out of range, get out your manual and check it out with an ohm-meter.

If your worried about damaging the carb by trying to wring too much throttle, then get a stop.

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