Throttle On Off at idle

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 I idle around for ages in bottom gear, and the way it was originally made me want to piss the bike off to a better operator than me.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?

gptech wrote:

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?

Yep, no change from my adjustment. I'm 19 - 99

gptech wrote:

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.

Thanks gptech! I tapped it a bit on both sides until i got to o 19-201 with no throttle stick. Throttle response is much smoother than before. Good enough that I think I'll stop tinkering before I screw it up somehow.

That's great mate, do you have any other mods to your bike or is it all stock?

If it's all stock then this might explain why only adjusting the TPS has made a difference.

For me I think it was a combination of several factors that smoothed this out, but the TPS angle adjustment made the most noticeable difference. To put it another way: In hindsight I probably would have been happy with just the TPS adjustment, but I wasn't happy with just the other things I tried. That's why I finally bit the bullet and beat on my bike.

Other things I did to lessen the on/off or "jerky" throttle response:
- Lubed my throttle cables.
- Adjusted my throttle cable free play to just a couple of millimeters in the idle position.
- Geared the bike down from 13/43 sprockets to 13/51.
- Swapped the stock 1/4 turn throttle tube for a 1/6 turn tube. This gave me less distance and time for the throttle to turn through the dead zone near idle.
- Adjusted the idle speed (at the same time I made the TPS adjustment.) I rode the bike around my neighborhood for 1/2 hour while picking the idle speed I wanted. I was amazed at the effect of different idle speeds on the bike near the dead zone RPM range. In the end I decided I preferred the upper end of the recommended factory idle RPM range. I set mine near 1650 RPM.
- Sprinkled magic elf dust on my air filter after cleaning and re-oiling it.

My intake & exhaust systems, and CO settings are all still stock.

Finally got rid of the nasty on/off throttle problem I had (still not as good as a carby, but alot better than what the bike was originally like), I blanked off the AIS port.

My bike had the GYTR muffler fitted to it when I bought it and I had no reference to how a standard wr250r's throttle was like. All I knew that it was really bad, and I wasn't going to put the stock muffler back on.

I had the CO mixture set at +10 if I had it any lower you could tell that it was lean.
I fitted my wide band o2 gauge with the AIS hose blocked and it showed the bike was way too rich, around 12:1 at idle. I adjusted the CO to -10 to get the mixture to 13.8:1, any leaner and the bike wasn't happy.

Unplugging the AIS hose and the mixtures went up to 17:1, crappy throttle response.

So, if you have a aftermarket muffler or you've removed the butterfly valve in the muffler then you need to also block off the AIS as well.

I blanked off the AIS port by putting a piece of sheet aluminium between the flange and the head, I left all of the AIS assembly on the bike with all the hoses connected.

The only mods that made any major difference to my bike was blanking the AIS and screwing the idle air bypass all the way in and using the butterfly stop for the idle speed adjustment.

Glad you got it figured out.  This is the first I've heard of anyone removing the AIS and not blocking the port.  It's a known issue that'll affect fuel mixture and EFI operation.  Google for "WR250R AIS removal" and you'll see what I mean.  There a quite a few homemade and professional plates made to block the port.  Here's one example..

After much reading and research I added the "Throttle Tamer" by G2.  I'd say that the bike has now become as responsive as it can be for a FI bike.  See here: https://wr250rforum.forumotion.com/t405-tamer-throttle-tube

Are there any other options to fix it? Or have most people just accepted that their bikes are the way they are? I love EVERYTHING about my WR250X except for the on/off throttle jerkiness and I really don't want to sell the beast :(

Turned the idle air screw all the way in and installed a cbr600r idle cable, running my idle around 1600 sometimes I turn it up a bit to 1800-2000ish, seems to help a bit. CO was originally set at -2. I've tried numbers from -10 to +10 and I've decided that it's best around 0 (couldn't tell tooo much of a difference honestly).

Adjusted my TPS from 16-97 to 19-100 last night and it helped the jerkiness a lot, the jerkiness persists and is still quite bad esp in 1st and 2nd gear but the hard engine braking is pretty much gone thankfully

The only other things I can think of doing are power commander V mod or the G2 throttle tamer at this point, feeling very discouraged ugh... don't want to get the power commander and for it to STILL not be fixed :(

I've just been getting used to feathering the clutch at low speeds, especially in first. The snatchy throttle was a bit of a shock when I test rode the bike. Now, other than being a little loud with the revs, first gear maneuvering is smooth.

Plebeian wrote:

I've just been getting used to feathering the clutch at low speeds, especially in first. The snatchy throttle was a bit of a shock when I test rode the bike. Now, other than being a little loud with the revs, first gear maneuvering is smooth.

Yeah I know man I've been feathering the clutch too in 1st and 2nd to smooth it out since I have no choice but it would be a lot better if I could fix the throttle snatch completely, or atleast eliminate most of it...

It's really annoying when rolling on the throttle while cornering and while lane splitting/filtering. I imagine it'll be very annoying when I take it off road too which is planned for the future.

The bike is smooth everywhere cept when you just roll on the throttle. It lurches as if my chain is set with 5 inches extra slack lol. (Chain and sprockets are in good health, tension at 11mm).

So the options to fix the on/off effect are:

-TPS adjustment
-CO settings
-Cracking open the throttle blades slightly
-Raising idle
-Fuel programmer
-G2 Throttle tamer

4 down 2 to go for me. Not sure if the throttle tamer will be worth it but a fuel programmer seems to be the solution for many, albeit an expensive one.

3rd option for me would be to sell this annoying WR250X and go and buy another one that doesn't have this bloody on/off effect hahahahaha.

Do you guys reckon this problem is absolutely fixable on each WR250R/X that has the problem or what? I mean... as if it isn't 100% fixable! :/ don't have a good feeling about this since the TPS adjustment didn't do as much as I had hoped.

nibbana wrote:

Plebeian wrote:

I've just been getting used to feathering the clutch at low speeds, especially in first. The snatchy throttle was a bit of a shock when I test rode the bike. Now, other than being a little loud with the revs, first gear maneuvering is smooth.

Yeah I know man I've been feathering the clutch too in 1st and 2nd to smooth it out since I have no choice but it would be a lot better if I could fix the throttle snatch completely, or atleast eliminate most of it...

It's really annoying when rolling on the throttle while cornering and while lane splitting/filtering. I imagine it'll be very annoying when I take it off road too which is planned for the future.

The bike is smooth everywhere cept when you just roll on the throttle. It lurches as if my chain is set with 5 inches extra slack lol. (Chain and sprockets are in good health, tension at 11mm).

So the options to fix the on/off effect are:

-TPS adjustment
-CO settings
-Cracking open the throttle blades slightly
-Raising idle
-Fuel programmer
-G2 Throttle tamer

4 down 2 to go for me. Not sure if the throttle tamer will be worth it but a fuel programmer seems to be the solution for many, albeit an expensive one.

3rd option for me would be to sell this annoying WR250X and go and buy another one that doesn't have this bloody on/off effect hahahahaha.

Do you guys reckon this problem is absolutely fixable on each WR250R/X that has the problem or what? I mean... as if it isn't 100% fixable! :/ don't have a good feeling about this since the TPS adjustment didn't do as much as I had hoped.

IMHO, Do the G2-Throttle Tamer next... less expensive than fuel controller.

nibbana wrote:

So the options to fix the on/off effect are:

-TPS adjustment
-CO settings
-Cracking open the throttle blades slightly
-Raising idle
-Fuel programmer
-G2 Throttle tamer

4 down 2 to go for me. Not sure if the throttle tamer will be worth it but a fuel programmer seems to be the solution for many, albeit an expensive one.

Great list.  I'd also add verifying correct throttle cable free play of no more than 3 to 5mm.  Too much free play increases the throttle time spent in the on/off idle dead zone.

I've experimented with idle speed changes a bit. Higher idle speed certainly lessens the off-idle twitchiness. But I can't help but think that raising the idle is mostly a workaround that gives a feeling of relief from the problem by requiring more clutch work moving on and off of idle.

The PCV programming mods likely work because they change the actual EFI fuel mapping in the low RPM range.  I think CO changes may do that too, and only at the low RPM range. I don't have a PCV but have discussed this with a few riders that do.

I've had good results and no more complaints with the combination of idle adjustment (currently running somewhere between 1650 and 1700 RPM), TPS adjustment, throttle cable free play adjustment, and G2 throttle tamer.  I have stock exhaust, no programmer, and did not mess with CO settings.

wwguy wrote:

I've experimented with idle speed changes a bit.  Higher idle speed certainly lessens the off-idle twitchiness.  But I can't help but think that raising the idle is mostly a workaround that gives a feeling of relief from the problem by requiring more clutch work moving on and off of idle.

If I decide to do something, idle speed will be my first adjustment. I think I am running a little low anyway.

Yet another update on the snatchy throttle issue.... I've been running a 13 front and 50 tooth rear sprocket.  I just put on a 14 tooth front and the bike smoothed out even more.  I took an 8 hour ride yesterday covering over 200 miles and I didn't notice the jerky, snatchy, on/off throttle at all.  Perhaps I've arrived!

Thought I'd update everyone. I ended up buying a PCV(fuel + ignition) and used the stock map with my fully stock bike for a few months. It improved the snatchy throttle a bit, I think enough to justify the price of purchasing it if it you intend to keep your bike stock. What made the most difference for me was when I bought and installed a Q4 + megabomb header and did the flapper mod a couple months ago and switched over to Nicks V2 map that I got off the WR250R/X facebook group which is pretty much made for the exact mods I have(Nick has a Powercore 4 with baffle).

I'm really happy with the bike now. There's still a tiny bit of a jerk in 1st and 2nd but nothing to complain about. It's a fraction of what it was like bone stock... and with the increased throttle response and slight power increase all around, this bike rips! Especially for a 250cc.