sticking throttle

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May 3, 2001
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#1
Three rides ago the throttle on my 2002 yz250 stuck open for a moment . I checked everything ie pulley , cable , spring retainer position , dirt etc . All perfect ! Last ride it happens again ,scary !
While loosening the carb top I hear a clicking sound from the slide being struck by the tps position roller. With slide out of carb I can and pulling tps up , I can easily recreate this condition of the tps stuck in the wfo condition . As i loosened the sender unit screw slightly the binding stopped , tightening it brougt binding back.
On stripping the tps unit I saw a very distinct bright wear mark on the shaft . I used 220 grit emery paper to sand down the shaft and on re-assembly all binding was gone.
the tps unit spring probably accounts for a third of the slide return force and if it is stuck it will send wfo info to the advance/ retard
progam,causing the mystery sticking throttle ( I think ) . Will be
trying it out this weekend !
 
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Sep 30, 2002
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#2
YOU, are lucky!! Dec 21, 2003, my throttle stuck twice with me on my 2000 KX 250. One time in the woods, I managed to catch it and stop in time. I checked the cable routing, slide, etc. Could find nothing wrong. So I rode it again the same day. Well, coming up to a face of a jump, I had the speed to clear it so I let off the throttle and it kept on getting it. The result: It put me in the hospital for 3 days with 2 fractured vertabrae, and 3 broken bones in my left foot. When I was able, I searched everything on my bike to find out what happened. The throttle cable was ok, no binding, no air leaks, (the only way I could check for air leaks was to make sure things were tightened up.) The inside of the carb was clean, no sand in the slide or nothing. The ONLY thing I found wrong was a little sand in the bowl. The sand was just small enough to maybe get sucked up in the main jet and possibly get stuck preventing the needle to properly seat in the main jet. Highly unlikely, yet possible. I talked to a mechanic and he suggested that I shorten the slide spring a 1/4 to 1/2 inch. He said that the stock springs are really to long and get all jumbled up when you have the throttle open. He said the spring could have possibly gotten in a bind on the solenoid shaft keeping the slide from going all the way down. The result would be a partially stuck throttle which is what happened to me. I didn't believe him until I could observe it myself. YES, the spring can get jumbled up in that tight space and YES, It can get stuck on the solenoid shaft. So I shortened it and observed it. So far, from what I can observe, the spring can't get caught on the shaft at all. It's fitted just right and it returns the slide just fine. I am not yet able to ride the bike but as soon as I can I'm gonna try it out, VERY CAUTIOUSLY of course!! A friend of mine said he'd take it out first if I was scared of it. I may just let him do it. A stuck throttle on a 250, 15-20 foot in the air IS NO PLEASANT DAMN FEELING!!

Wish you the best of luck. If you have any questions or suggestions feel free to email me at: rutbuster1@charter.net
 

intmach

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#3
I know this an old thread. But has anyone else had any throttle related problems on there 02 yz 250. or the 125 also. Yamaha was supposed to have fixed that in late 01 for the new 02 models. Just wondering. My throttle stuck on the face of a jump 2 weeks after i bought it. In that accident i broke my pelvis in 3 places and also split my sacrum in half.

I am not wanting to do anything but warn others about this potential problem and just verify that these are rare and isolated incidents...

Paul

Intmach@yahoo.com
 

Jaybird

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#4
Always take a good look at the slide face itself. The coating can peel off.
 

biglou

#5
Wasn't there a recall at some point for this? New throttle wheel or something? I could be thinking of something completely different, or a different brand, but I think I remember a recall with Yamaha throttles a while back. Late 2001 seems about right, too.
 

elf

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#6
intmach said:
I know this an old thread. But has anyone else had any throttle related problems on there 02 yz 250. or the 125 also. Yamaha was supposed to have fixed that in late 01 for the new 02 models. Just wondering. My throttle stuck

Intmach@yahoo.com

The older bikes like my 99 and 00 had a recall on the throttle wheel in the throttle housing. They gave us a larger wheel to keep the throttle cable from coming out and getting jamed. I thought the problem was fixed on the newer bikes. Anyways I feel your pain, nothin worse than having your throttle stick at the wrong time.
 
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#7
I think the recall applies to 2002 YZ's as well. I know for a fact it included 2001 as I took a trip over the bars in a rythm doubles section when my throttle got stuck wide open. I replaced the roller wheel and it hasn't happened since.

Yet another good reason to keep at least one finger on the clutch lever at all times. I know it is difficult to remember what to do when something goes wrong, but at least you will be a little more prepared.
 

viking20

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#8
Over here we never hear about those recalls.....A vet rider in our club seized the throttle in his -99 yz 250 , one of the scariest crashes Ive ever seen , on a really big table-top..He was heavily injured , worst of all a new shoulder joint was needed.He didnt work for over 6 months , and will never ride again......
 

intmach

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#9
Actually from what i remeber the recal was from 97-01. I had an 01 that never had a problem. I replaced the Wheel with the larger one just to be safe. I know that this problem has occured on my bike (02) three times. And it's the wheel that is catching the wire and pinching it inside the throttle assembly. The backlash has been removed from the cable as per the manual. I think I will put a motion Pro on it just to end the problem once and for all. Pretty cheap solution if you ask me. I just hope noone else finds out the hard way that their still maybe a problem..

Thanks for the replys..

Paul
 
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Jan 17, 2004
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#10
Just had my throttle stick on my 03 kx 250. I hit a tree stump because of it. I thought I broke my foot. I am still walking but I am walking on the front of my foot instead on the heel. I can't wait for this pain to go away.. I believe my cable was bad and it was sticking on the throttle housing. The pressed fitting was ripped off the cable. I replaced the cable and I am a little leary of driving it now. It is an awakening when this happens to you. I am pretty sure I am pretty sure I corrected the problem but I am still cautious.
 
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#11
I'm sure everyone knows this, but I want to throw it out there. If your throttle locks wide open, mash the rear brake and lock the wheel up. This will definately shut down the engine.

A stuck throttle always happens at worst possible time, it's hard to keep a clear head when it does. My last one happened halfway up the face of a medium table top. I set up for it ok, but when I throttled back, the bike had other ideas. It's an odd feeling taking off at full throttle when you only planned on a 1/4. I landed ok, shot across the track, over the berm, and off the track I went. Must have look like that MX Unleashed commercial. (at least thats how it felt to me) I pulled in the clutch and stopped without going down. Engine still wide open. I tried the kill switch, but it didn't work. So in my infinant wisdom, I chose to remove the plug boot. The engine did stop after that. But not before it shocked the $h1t out of me. It was such a shock, literally, that I lost my balence. You guesed it, after my graceful recovery and stop, l wound up falling anyway.

After I regained my composure, I got up enough nerve to start it up again. The bike fired up ok, idled well and shut off with the kill switch. Seemed like an odd occurance to me. I rode the rest of the day without incident. Although I was a bit gun-shy of that table top.

I have now promised myself to use the rear brake if it happenes again.

Hope this helps, Steve.

P.S. I picked up a few bottles of carb cleaner and went to town the next day, just for G.P.
 
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Dec 19, 2000
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#12
I'm looking for details on the '97-'01 Yamaha RECALL NOTICE for the throttle pulley. Mainly a referrence number. I learned this in 03 from this site. I stopped at a dealer and they knew all about it - told me to bring in VIN# and they'd give me the part. But I broke my wrist soon after and didn't ride anymore in 03, Then in the winter of '03 I bought a rebuilt YZ125 and rode it in 2004. I sold the 125 this spring and was prepping the 250 (install a new throttle cable bought in 03). Figured it would be a good to install a new pulley too so I went to the dealer (Northshore in Eastlake, Ohio) to pick one up. Well, they really dumbed up in 2 years! No one there knew anything. They gave me a Yamaha service # (800) 962-7926 so "I" could call. I called the number and after 5 min of menus, garbage, etc. the machine hung up on me-I was told the lines were too busy!! I COULDN'T" EVEN HOLD ON IF I WANTED! The message also told me my dealer "was the best source of info" (right!) and to "check the web site." I went to the website I learned it wasn't accepting emails and was referred me back to the number that just hunk up on me!!!

If YAMAHA reads this - I like your bikes but if this is how you treat customers regarding safety issues, maybe I'll look at Honda next time? Also, consider yourself "on notice" should my throttle stick and I'm injured as a result!!!
 
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#14
I thought I was the only one that ever had this problem, everyone thought I was crazy when it kept happening to me on my 2000 yz250. Mine stuck a couple times on the same day always on the face of a jump. the last one almost wrecked me, when it went wfo i grabbed the clutch and front brake going up the face of a tabletop(dumb I now know but it was in a panic) the bike endoed but I stayed on, sprained my shoulder, just lucky it wasnt a whole lot worse. Took it to my local yamaha dealer and they did the recall, also loosned up my throttle cable, I havent had it happen again yet but then havent been as aggressive on it either. Won't have to worry about it now though, someone stole it last week, wish I hadn't gotten it fixed now, hope it happens again to the thief. Looking at a new 05 now. maybe.