Throttle On Off at idle

same bike, smaller wheels
both have the same motor

My 2008R has a BAD stumble/jerkiness problem off idle so I just read this theread to see if I could learn anything.

Being a lazy guy I tried a variation of the high 5 approach of just tapping on the TPS with a punch to move it without loosening the torx fasteners.

Rather than tapping on the "top right hand corner" to rodate it CCW, I tapped down on the rear fastener boss right above the torx bolt hole.

This moved my setting from 16-96 to 19-100 BUT it caused the throttle to drag to the point that it would stay at WFO.

After thinkintg about this I realized that I hadn't simply ROTATED the TPS but rather had moved the back side down with moving the front side.

This apparently created a bind inside the TB that put the drag on the throttle.

SO still being lazy I tapped up and back on the front fastener boss to, hopefully, get the TPS recentered on the throuttle shaft and remove the bind.

This worked to eliminate the bind but changed the reading to 19-102.

I haven't put things back together yet to see the rusults but I don't expect that the 102 vs 100 is significant in that the computer probably just ignores any value over 100 and even if it didn't the difference at higher throttle opening should be insignificant.

I'll let you know how this works after I test the bike.

I checked my values in diagnostic mode just now.

I think this is out of spec... 16-92. I guess I'm off to Sears for some security bits.

I have PCV w Autotune with which I had been unable to cure the MAJOR off idle stuble (with mixture changes and accel pump feature of the PCV/Autotune)

I realized that the idle speed was down at the bottom end of the spec or lower. I also found that increasing the idle speed seemed to SOLVE the big stumble upon opening the throttle :<) Strangley, even with the idle screw so loose it was beyond where the O ring provides locking drag the idle speed was a little below the max spec of 1650? However 1600+ was sufficient to fix the stumble. I sort of rest the PCV map and Autotune target AFRs and haven't ridden it enough to do any map adjustments. BUT it is now running fine.

Re: The resetting of the TPS to 19-102 didn't seem to fix the stumble (may have helped a little)? The calibration of the PCV is done as one of the last steps and basically takes the closed and open positions and makes them 0% and 100% for purposes of the PCV.

My net take is that the first thing I'd try if I had a stumble is increasing the idle.

Well I got mine adjusted to read 19 and 96 now.

I pretty much removed the throttle body to get access to those security screws.

Upon firing it up the idle would rise and fall semi-rapidly and then the bike would die after a few seconds of that. Once I recalibrated the TPS in the Power Commander program idle was fixed. I tweaked the idle setting once everything was working.

Hard to say if there's a difference yet. I took it down the street to Home Depot for some hardware, but it's such a short trip I didn't notice anything. Over the next few days of commuting I should be able to make a determination.

The TPS adjustment is worth while.

Before, if I would ever-so-slightly open the throttle the bike would die. There was a dead spot there. The only way to get past it was to quickly rev beyond that point.

That dead spot is now gone. Low speed throttle openings are much less choppy. I am pleased.

Kansas Bob wrote:

I put on 20 miles this morning, and it rained over night for the first time Weeks!! I even got to play in the mud a little!

Bottom line is everything down low is much improved , and performance hasn't suffered. Back in April I did some technical riding in Arkansas and dumped twice in first gear because it just wouldn't pull down low. It would either cough and die or blast me off the trail when I opened the throttle. This morning I was able to actually get it to "chug" a little........ It sounded like a flipping KLR

I checked the numbers again, and it's holding at 18 - 100, I'm happy with it the way it is now, and my 47 tooth should be here today. Hopefully that will improve Reeally slow riding even more.

Up Date:
In July I put on 600 miles in Colorado. Very happy with the bike now! Throttle Snatch in the tricky low speed rock sections was minimal, and overall the bike preformed excellent!!

Current set up is Michelin desert front, 120- T63 rear, 44 tooth rear with stock chain, Factory lowering adjustment rear with forks moved up as far as they will go, Factory fork oil lever lowered 3/4 inch, and TPS re set to 18-100. Bike is 100% stock otherwise, and I run Lucas fuel conditioner / upper cylinder lubricant which really does help the power, and offers the fuel pump some lubrication.

Thank you Kansas Bob !! Your foto's and tool helped so greatly that once I understood the safe (lets not break anything else) procedure and with my Machinist Tradesman knowledge it only took maybe 15 minutes to do the actual adjustment once the plastic was removed. The only thing I did differently to pry the the throttle body aside to access the bottom screw, was to use a wooden handle mallet and entered the frame a little further back where I could pry against the flange with the hole at the back end of the TB. Wood is better than plastic screwdriver handle because it has better friction and won't slip. But the best info was accessing the Diagnostic tool in my gauge, rather than going out to buy a sensitive voltmeter and poking into wire insulation.
This forum is a great source of info and it is all because of the membership. I am very greatful.

YAMAHAPPY wrote:

Thank you Kansas Bob !!

Glad it worked out for you! I really believe doing it the right way and loosening both screws is the best way to go. Since I did mine I've read a couple of times where people get the whole setup in a bind beating on it causing the throttle to stick at WFO.......... not good.

Today I was able to get out for a ride in the coastal mountains just north of Vancouver BC to try my bike since I've done the TPS adjustment. OUTFREEKIN STANDING !!!!!!!!! You members were absolutely right when you say that the effort results in a whole new bike rideability. I began with a diagnostic reading of 16-96 and bumped it up to 16-98. Up and down trails I can now easily feather the throttle controlling the acceleration, and the deceleration has no more of that terrible "engine braking" that wore out my arms big time. I can just coast if I want with no choppy throttle (almost like a 2 stroke). And as an added bonus, I can make wheelies in first gear with so little effort with the 13/45 ratio. The throttle response is snappy!
I've also just got my suspension back from FACTORY CONNECTION in Corona for a service since they re-valved it last year and FC did a great job again. We use them for all of our bikes. I now have a perfect bike after 4 years of ownership.

I just purchased my 2009 WR250R with 777 miles on it. It also had the on-off throttle at low idle. The throttle settings were 16-96. I had the dealer adjust it under warranty to 19-100.
I was surprised at the difference it made. Very nice. Thank you for the ideas.
Cheers
IdahoWR250R

HAppy New YEars folks !

My WR had the snatchy throttle off ide syndrome. I pulled everthing off to have a look at doing the throttle settings adjustment. But those bolts are intimidating to get to.

Instead, I got my CO mode going so I could check my idle RPMS and adjust the fuel mix at idle. Turns out my idle was too low and I riched up the fuel mix a bit at idle. Seems to have smoothed out the snatchy throttle off idle a good bit. If you want to do this th einfo is in this thread.
https://wr250rforum.forumotion.com/t3769-wr250-r-x-built-in-programmer

Much easier than tackiling those bolts to adjust the throttle settings. I still want to tackle tha another day.

I adjusting the TPS yesterday. I ended up loosening just the front screw. I did so by grinding down (shortening) a t25 bit, and using a tiny 6mm wrench to turn it. It worked fine, if bit finicky. I used some tape to hold the bit in the jaw of the wrench, while inserting it from below, pulling the line from the radiator outwards and out of the way.
I couldn't get to the rear screw as there's way less room there, so I tried tapping on it instead from above. Nothing happened at first, so I proceeded to grind down the t25 bit further, to the point where the wrench no longer had anything to hold onto. The idea was to make my own little tool for this part. Turns out that's kinda hard without a dremel.
Getting tired of it all, I started tapping the unloosened screw again, and waddya know? It suddenly gave it, and started turning.
I adjusted it from 16/96 to 19/99. Having ruined the t25 bit, I couldn't tighten the front screw, but I decided to try the bike regardless.
I rode it for 6 km, doing about 60 km/h to warm it up a bit. It was below freezing temperature, so I'm not entirely convinced the warm up procedure worked. I don't even know if it would matter at all. Anyway, the bike didn't seem too much different. It might've been slightly better off idle, but it certainly wasn't the vast improvement I was expecting after what I read from others.
I*m going to get hold on another t25 bit, tighten up the TPS, and try the bike again once the weather gets warmer, sometime after march I reckon. I'll let you know then if there's an improvement.

i have an 2008 yamaha wr250r as well and i have adjusted my tps from a .63 to a .73 and i didnt feel a difference in the jerky throttle. is there anything that anybody has done that is a for sure fix to the jerky throttle. i checked the numbers on the diag and it said my bike is 17 - 97. how do i adjust to make those numbers 19-100 is it the same way i adjusted the tps. when i adjusted the tps i didnt know to check those numbers intill reading this post so i dont know if adjusting the tps made any changes to the numbers.

Bumping the idle speed up a bit and richening the CO up a bit fixed the jerky throttle on mine.

My 2012 with about 350 mi on her so far, has a bothersomly touchy on off bucking issue. I am so happy to find out that I am not alone in this issue. I will read and re read everyone's suggestions here and hopefully I can correct my issues too!

Hey folks....

I just had to register and let you know you've been an awesome help.

My TPS was set at 15/94, and I was able to adjust it up to 19/98, which improved the low end stumble a lot.

The CO was set at 4, perhaps by previous owner, I only adjusted it up one notch. My bike is fully opened.

Again, thanks a lot

My bike was like a lot of the ones mentioned previously. Atrocious, jerky throttle when opening from full closed.

So 1. Increased idle to 1700rpm hot.
2. Removed the throttle tube. From where the opening cable nipple is located (ok, ok...), using a 2mm drill bit I grooved the cable guide for about 20mm around the tube. Deepest at the beginning, then gradually getting shallower. This made a notable difference. Easy to do. There is a thread on how to on XT660.com, I think.

It's still a bit snatchy, but not too bad. I idle around for ages in bottom gear, and the way it was originally made me want to piss the bike off to a better operator than me. Now, it's ok. Not great, but ok.

Finally, an observation about the bottom end power of the WR. My bike will chug down to ridiculously low speeds in first without stalling. It does have a 48T sprocket, but my TTR250 has 13/50, down from 14/44, I think. The TTR will stall much more easily than the WR. It does not have the ability at extremely low speed that my WR has, which is understandable in one way, ie much later design bla bla, but the TTR is lower in compression. I know it's only academic, but the WR has momentarily got down to 4.7km/h GPS without stalling, whereas the TTR can only manage about 6, and usually it will stall at that.

I tried this mod on my wr and there was very little if any change. The tps in diag mode went from 15 to 19 after adjustment.

I think the only way to smooth this out is to eliminate the fuel cut on decel completely.

Have ordered a PCV, hopefully this will allow the decel to be removed.

The other ideas for this I found on supermotojunkie were to use a idle cable from a cbr600rr. http://supermotojunkie.com/showthread.php?66503-wr250x-no-external-idle-control-problem-solved!

BY doing this you no longer use the idle screw for idle adjustment. And this would put the throttle at idle in the range that stops the ecu from going into fuel cut and giving you a smoother idle transition.

I finally adjusted my TPS angle today and the difference is night and day for me. I bought my stock 2011 WR250R used last February with 800 miles on it. Between then and now I'v put 1500 mostly dirt miles on it and spent a couple grand on farkle to make it more nimble and capable on mountain trails. My previous mods included 13/51 gearing, steering stabilizer, suspension adjustments, and controls ergonomics (e.g taller and wider bars, lower footpegs, etc.) I also replaced the stock 1/4 turn throttle tube with a 1/6 turn throttle tube. The one thing that had been driving me absolutely NUTS was the throttle on/off jerkiness. I felt like a cowboy riding a horse that didn't have any speeds between "giddyup!" and "whoa!!"

My settings as found:
RPM: 1800
TPS: 16 - 97

My settings as left after adjustment:
RPM: 1650 (upper end of factory recommendation.)
TPS: 18 -100

Now the "on/off" experience is all but gone and I can put about in 1st gear at 3 MPH. Along with lower gearing and steering stabilizer, this is the most rewarding mod I've made to this bike. If I wasn't a hillbilly dirt rider and rode mostly on the pavement this mod would be at the top of my list. I wish I would have done it sooner.

Interesting that adjusting the TPS has all but solved the problem for some people and others it has made no difference.

My 2015 seemed to develop on-off at about 100 miles. Codes showed it to be set 16-98. I tried adjusting to 18 but it had 2 issues. First if i eased the throttle back it would only go down to 20, but if i let it spring back it would go to 18 ususlly but sometimes 17 or 19. Worse, the throttle would stick.

I settled for 17-100 which seems to have made the throttle smoother but only a little

pwlldvd wrote:

My 2015 seemed to develop on-off at about 100 miles.  Codes showed it to be set 16-98.  I tried adjusting to 18 but it had 2 issues. First if i eased the throttle back it would only go down to 20, but if i let it spring back it would go to 18 ususlly but sometimes 17 or 19.  Worse, the throttle would stick.

I settled for 17-100 which seems to have made the throttle smoother but only a little

You have to tap the opposite side of the TPS so it will recenter it.

Just keep going until you get to 19. For me it made no difference.

What has made a difference is I screwed the idle bypass screw in completely so all air now has to pass by the throttle butterfly. I adjusted the throttle stop screw at the throttle body, you have to remove the tank to get access.

My TPS setting is now 20-101, the transition at idle is just about right, very similar to a DRZ400 I rode on the weekend.

I have my CO setting at 10 up from 4 as I have a GYTR muffler fitted.

I also read that disconnecting the o2 sensor made a difference but I noticed none on my bike so I reconnected it.

I've done the TPS and CO adjustments and the final was to adjust my throttle cable to minimal freeplay. All three of these adjustments, combined, smoothed out the throttle.

JS5Owner wrote:

I've done the TPS and CO adjustments and the final was to adjust my throttle cable to minimal freeplay. All three of these adjustments, combined, smoothed out the throttle.

Have you checked what the TPS value is after you did the cable adjustment?