Jumpy Throttle fixed

[Tremor38]

My throttle has been extra jumpy during decel lately. The sensation is as if the throttle plates slam shut in two separate throttle positions as the twist grip is turned toward closed. When I had the same problem one year ago, I actually pulled the air cleaner and viewed the throttle plates. As I turned the grip toward closed, the plates would suddenly snap toward closed then re-open well before I had the grip completely returned (also well before any free play). I did not document the solution, so, now that the symptoms have returned 1 year later, away we go! The procedure involves moving the throttle sensor -the one that reads throttle body position- repeatly from stop to stop to re-establish a consisently good contact path inside the sensor.

Tools: Torx T20 security bit. Make sure the bit is short enough to clear the brake lines mounted against the frame.

Linkage access cover: Three Torx bolts of varying length. Raise the fuel tank for access.

Linkage:

Start of rotation: Make sure the key is off, or you will be fighting the servo motor.

End of rotation: Go through this cycle many times rapidly.

As a bonus, I sprayed oil into these lube holes at the end of the shaft, RH side:

Why not just put it in a higher gear and go to WFO several times, you ask? That helps but the 'fix' it doesn't last for longer than a day or two. The movement will be slower using the twist grip, and I don't think anyone really wants to put undue strain on the engine by snapping the throttle from stop to stop, several times in a row while it's running, regardless of the selected gear and RPM. Also, stop-to-stop movent is not possible via the grip with engine off and key on. You only get a very small movement (maybe about 5% deflection). The most effective and long-lasting way is to use rapid, repeated stop-to-stop movement via the method I've shown. My throttle control is as smooth as glass (comparatively) now. The fix should last the rest of the season, as it did last year.

 

[Tremor38]

Double post

 

[carrot]

how many miles you have on your bike ? i have been noticing the same thing also my bike doesn't feel happy revving above 5000 what i been doing is with the key on before i start i twist the throttle full open then let it snap back closed five times this works sometimes going to be replacing the throttle body position sensor to see if that helps . i have 30000 miles as of now seemed to have stated acting up at around 12000 miles .

 

[Tremor38]

how many miles you have on your bike ? i have been noticing the same thing also my bike doesn't feel happy revving above 5000 what i been doing is with the key on before i start i twist the throttle full open then let it snap back closed five times this works sometimes going to be replacing the throttle body position sensor to see if that helps . i have 30000 miles as of now seemed to have stated acting up at around 12000 miles .

I have about 25,000 miles give or take. Keep in mind that you are not moving the throttle body position sensor very much at all when you take the grip stop to stop with engine off and key on. You ARE moving the accelerator position sensor stop to stop, which is totally separate. The throttle plates only open about 5 degrees with key on and engine off, twist grip fully twisted. What happens to the TPS is we ride around so often at small throttle openings that the rest of the range can get buildup of plaque and such from comparitive lack of use in that range.

 

[carrot]

Cool thanks I will give this a try .

 

[carrot]

Still having this annoying problem that comes and goes so replaced throttle body sensor and can tell a much smother throttle response will see if it stays that way and here's some pics of what I found

 

[whisperquiet]

I just completed the first valve clearance check on my 2013 S10 at 27,300 miles. My bike had the jumpy, glitchy throttle for some time prior to the service and I chose to follow the OP's suggestion to rapidly cycle the throttle sensor. The air filter was replaced at 24,000 miles and I replaced the orignal sparks plugs when checking the valves. I am happy to say that my S10 runs smoother than ever with great throttle response and no "jumpy" throttle anymore. This is something one should check when you have occasion to remove the air box for any reason.

JUST FYI

 

[Harry Dresden PI]

Thanks for photos and post

 

[BenSuper10]

I have this exact same problem on mine. It is driving me nuts!! I had a 700km ride out this weekend and it was this for the whole trip. it can't be good for the engine.
I have a small video of my jumpy throttle but I'm not sure If I can upload it here?

Just few questions!!
Do I take off the accelerator position sensor or do I just physically move the linkage back and forward a few times to clear any build up of crap?
Do I spray any penetrating or lube oil (WD-40) around the linkages & springs?

I've checked the settings on the diagnostic and both position sensors are all in tolerance. I haven't checked the full range of resistance through them, which I will check today to see if the resistance drops at any stage during the closed to open twist.

It only happens when in slow/slowish moving traffic and in a certain rev range. My throttle jumps from anywhere between 2K-5K to 0.5K, it's really annoying and deadly on bends, it feels for a few milliseconds that the power drops completely and I'm going to drop the bike because of it.

I've no problem with it when I give the throttle full whack on the road or at idle!!

My video shows when I'm in neutral and idling, I twist to about 3K revs and the revs drop and fluctuates back up again

Hopefully your advise clears it up. I'll let you know how I get on later when I get to do it.

Edit: Update!!

I did your procedure earlier and WOW, the bike runs very very smooth, the smoothest I've riden it yet, Brilliant fix!! Thanks Tenerator12

While I was down there I checked the resistance on the accelerator position sensor and the throttle position sensor, the thing is, is that the tolerance is not in spec according to the manual.
Specification: APS = 1.2 to 2.8 KΩ, mine was 0.95 to 2.10 KΩ.
Specification: TPS = 1.2 to 2.8 KΩ, mine read 1.0 to 2.25 KΩ.

But, when all connected back up, the tolerance reading on the diagnostic is perfect.
Specification: d:01 = 9-20, mine read 17
Specification: d:14 = 12 -22 & 97-113, mine read 15 (closed) & 100 (open)
Specification: d:15 = 9 -25 & 97-113, mine read 16 (closed) & 101 (open)
Not worried though because she's running as sweet as a nut!

 

[Geekay]

just found this threat from searching - i also had a very jumpy throttle and the reported "neutral throttle stutter" - I'm pleased to say that this has fixed it and vastly improved my throttle response and control.

Do we know if the symptoms - even with the "cure" signal the start of the end of the throttle position sensor?

I.e. does it come back and the only real fix is to replace the sensor? or does this fix seem to work for an extended period of time?

Thanks again - great forum and great info!

 

[tpak]

My throttle is having this issue as well. I'm going to try this when I replace the air filter in the next garage session. I do wonder if what carrot is showing below could be cleared up with a quick blast or two of contact cleaner before replacing the part? Was it worn or grungy, hard to tell from the pics?

In any case, I'm hoping the OP's solution is all I'll need!

Still having this annoying problem that comes and goes so replaced throttle body sensor and can tell a much smoother throttle response will see if it stays that way and here's some pics of what I found

 

[rbmgf7]

Sorry to revive this thread but I figure I add to it since it already has pics.

I've done these instructions a couple times now but the problem always comes back about half a day later. Starts smoother than what it was, then a couple hours in it immediately jumps right back to having the snatchy acceleration and dead deceleration in the 2-3k range.

I went ahead and removed the sensor and sprayed inside it with MAF cleaner and rotated the sensor back and forth numerous times (the part where it couples with the throttle bodies has a small opening into the sensor). I repeated this along with blowing it out with air.

What I assume to be was dielectric grease coming out. I guess dirt might be getting into those two tiny ports on the throttle bodies and making their way into the sensor; especially if you ride in dirt and rain. Maybe it's caking on the contacts where it slides? Seems unlikely but it's a guess.

I went for a short ride and I could tell that this solution was way smoother than just working the linkages back and forth. It's still early but I'll see how it goes. I still need to do a sync and maybe adjust the sensor settings in the instrument cluster but I want to see how the throttle responds with some time.

Regardless, it does seem like the sensor is the root cause.

TIP: if you want to save the hassle installing those security screws, go get some allen head bolts. I think they're M5's. I just happened to have a couple lying around that worked so unsure on the size.

 

[rbmgf7]

No dice. I guess I spoke too soon. It did last longer than before but when it gave, it got knarlier than before.

I took the sensor off to test and the resistance bounces everywhere and isn't consistent in either direction for either wiper.

I did find this

Since the OEM ones on the ST are blank, it leaves me to believe that these might be the same one. Anyone buy one from here or should I be the guinea pig?

 

[WJBertrand]

No dice. I guess I spoke too soon. It did last longer than before but when it gave, it got knarlier than before.

I took the sensor off to test and the resistance bounces everywhere and isn't consistent in either direction for either wiper.

I did find this

Since the OEM ones on the ST are blank, it leaves me to believe that these might be the same one. Anyone buy one from here or should I be the guinea pig?

Measure the resistance change from full open to fully closed. If the replacement is the same as OEM it should work. I replaced a TPS on my Honda ST1300 using an aftermarket one intended for a Honda car. It worked fine. Trouble with the ST1300 is that Honda does not offer the TPS separately, only has part of the entire throttle body assembly. Sometimes, the installation doesn't use the entire range of motion so it's also really important to adjust/calibrate the TPS so that it provides the same range as OEM when installed. Most TPSs have slotted mounting holes to allow for the adjustment.

 

[Ridon29]

You sir are a genius. My Xt has gone from hesitating misfiring and general bad running to super smooth power delivery... thanks very much

 

[Ramwyn]

Is this fix applicable to both Gen 1 and 2 bikes?
I've tried just about everything else to try and cure the jumpy throttle and lack of deceleration at low RPM.
This includes ECU remap, TB screw adjustment + synch, CO increase, and throttle cable free-play reduction.
It's spoiling what is otherwise a very capable motorcycle

 

[Farbar]

Replaced TPS with a new one from alibaba for $50 and all is well again. (Thanks rbmgf7)
I think running around the same speed a lot of times , or on cruise around same speeds creates a resistance spot in the TPS and whenever your bike decells or accelerates accross that spot, it can hiccup. TPS is just a fine scale potentiometer. I also changed my accelerator sensor while I was in there (reads the input from your wrist) as that can cause the symptom too. You can spend some time in diagnostics 1 and 14 to check the readings, VERY slowly moving from closed to WOT. Any jumpy or missed numbers, is highly suspect. Plus you get to see the initial settings. 1 should be between 10-20 (15) and 14 should be between 12-22 (17) Rotating them on their mounting screws adjusts the numbers

 

[Rewop]

Just wanted to say thanks Tremor38, this afternoon I carried out your fix as described above, and have just been for a test ride - not a hint of a stutter or throttle jerkiness, the bike is running smoother than it has for weeks. My 2013 Gen1 bike has 18,200 miles on the clock, and I think I first noticed the deterioration in throttle response around 15,500 miles and this has gradually got worse to the point where I wasn't confident on slow speed turns/roundabouts etc, so finally faced up to sorting out the problem today.

I removed all of the left hand side panel to make access easier but It may be possible to do this job by just raising the tank. I kept the tank raised and held back by using a 27.5inch (700ml) mountain bike inner tube. I stretched from the rear carrier over and around the top of the tank, it fitted perfectly without being to slack, and no danger of scratching anything - as long as you keep the valve out of the way

I wasn't sure how many times to cycle the TPS so did it about 100 times - 5 x 20. Also I haven't seen Torx bolts with the centre post in the bolt head before. I don't think these are common in the UK, but fortunately I had a set of bits with hollow points. I only have a standard socket set and this with the bit in place was to large to fit in the available space to undo the bolts, so managed by wrapping a bit of tape around the hexagonal end of the torx bit and fitted a small six ml ring spanner over it, fortunately the bolts weren't done up too tight. I took my time and did the whole job in about an hour and half. If it needs doing again it should take less than an hour now I'm familiar with the procedure

Thanks again

 

[Ramwyn]

Just thought I'd chip in with the solution that worked for me........

I removed the TPS and cleaned it out using contact cleaner and compressed air, whilst rotating the shaft.
Disappointment later followed when my test ride revealed this had not cured the snatchy throttle (at 2-3000RPM).

I was now running out of options (already done ECU remap, TB air screw adjustment, TB synch, CO increase, and reduced throttle cable free-play). However, a telephone call to my ECU remap man (Grant at Wiz Performance) provided a glimmer of hope.
He suggested the fueling was being leaned off at low RPM, and it was caused by the Oxygen Sensors.
I just disconnected them at the loom, went for a test ride and well, elation followed - the dreaded jumpy throttle was cured!
To say I'm happy is an understatement. I'd been thinking recently of selling the Yam as the snatchy throttle was spoiling what was otherwise a very good bike that really suited my requirements.

As for the Oxygen sensors, it seems their purpose was to ruin the smooth running of the engine for emissions reasons.
I have now removed them and inserted some Stainless Steel plugs in the downpipes.

 

[Cycledude]

https://www.answers.com/Q/What_does_an_02_sensor_do