Carb Stuck Open

Help please!!!

I romoved the carb from my '00 WR400FM for cleaning. When I remove the slide by rotating the throttle shaft until it disengaged from the slide. It throttle shaft stuck in the open position. I replaced the slide and confirmed that nothing was stopping the slide from dropping but the throttle shaft won't drop below about 90% open. It moves freely from 90-100% open but won't drop.

I faintly remember someone warning me not to open it to far or I would damage the TPS. Did I damage it? Has anyone else experienced this problem? What to I do to correct my problem?



get brutal.

no the tps has to be smacked about.


an off beat question while were on carby's has anyone played around with their tps and set that up properly?

I don't recall that issue being addressed much by this forum. But it may be worth looking into. A guy in my local area does a lot of work on Yamaha 4-strokes. I talked with him last week about having my cams degreed. It's about 6 hours of labor (close to $400) but he sets up the motor and carburetor to perfection. 'Calibrating' the TPS is included in that. He told me that you need some kind of special tool to do that and we didn't get into specifics.

An interesting thing he told me was that in EVERY SINGLE bike he's worked on, the cams and TPS were off at least a little bit and needed to be adjusted. I'm going to save up the cash and get this done sooner or later. Gentlemen, there is a lot of power trapped in our bikes, just waiting to be unleashed, as a result of 'variations in production'.


SFO is selling his calibrated cams and VT camwheels on this very page.

your friend will take less than six hours to do this. it's more like two hours. i had to measure all the cam lifts etc, you just want to get on with it.

i wouldn't call it a lot of power, a noticeable difference maybe.

i consider it a great disappointment that i didn't hang around long enough to try different timing sttings. there's no reason why the wr has to have such poor grunt off the bottom. the answer is in the cams or ignition i'm pretty sure. cams probably.

but first you have to get your jetting spot on to notice anything.

as for the TPS, it's well recorded that all you need is a multimeter. Clark said that he had advanced his and it had improved it. i don't think that's right. might be, but i don't think so.

he probably found that the engine was able to burn what were very rich settings all that long time ago-at least phew! er! a year :D

try doing a search and looking for clark mason and tps.

sets the carburation to perfection!!!!!what a load of twaddle. you've been suckered again!

the people who have got the carburation to perfection are on this site, the info is FREE and we're not full of s***!

how about sending me $400! :):D


Hey Jerry,

There is a locking tab behind the throttle wheel, to help keep the carb open for service. Just put a little screwdriver in there, and push the tab inward.

Thanks Jam....

I was wondering how many post's it was going to take to answer Jerry's initial question....Some days it goes on and on and on and on and on....

Bonzai :)

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