Snatchy off-idle Throttle Response fixed!

I tried increasing the TPS setting to about 102 with a little success.
I tried adjusting the CO to 10 with little effect, it was nearly there originally.
I tried drilling out the idle circuit to raise idle speed to 2250 or so with a little success.
I tried a programmer with no success. Threw it in garbage, that helped a bit!

The higher TPS setting made the throttle a little more responsive or with less hesitation when going from idle off throttle, to light throttle application.
The increased idle speed helped cover up the snatchy throttle response or the transition from no power at idle to power when the throttle cracked smoothness.

The solution though is so obvious I am amazed I did not figure it out sooner! This required 1 more adjustment that all the other adjustments were attempting to solve though not directly, or effectively.

Now I enjoy and love my WR250R with a smooth idle transfer at light throttle applications for Trials Riding.

Anyone want to guess the solution before I tell you?  Any interest?

Throttle cable slack or free play.

Husqvarna WR250?  

A different throttle tube might do the trick also, with a different cam profile.

Bumped the throttle blades open slightly.

Geared it down?

OK...that should do it! What's the answer!

I think he left laughing.

Welcome! Nice first post. I give up

Traded it in on a Beta?

Thx for the reply's:

The Solution to the off idle throttle hesitation, is to turn inwards the FI throttle body stop screw, just like you do on a Carburetor when you adjust the idle speed and the throttle blade location.

I turned in my set screw a little more than 1 full turn. This raised the idle speed to 3000 RPM or so. Then I turned in the other plastic idle speed screw on Left side of throttle body all the way in to lower the RPM resulting in a 2500 RPM idle speed. Perfect!

To do this, Remove fuel tank and hang on handle bars for support, and you can see the stop screw and lock nut on the left side from the top under tank.  The nut is 8mm and the allen wrench is 2.5mm long arm. Loosen and adjust with the engine running and can adjust to RPM using the factory Tachometer.

See pics

Liberty1 - Wanted to warn you about another thread on this forum that others have said about problems moving the TPS past 99% that it can stick open and hang up. will post it up if I find it, just wanted to let you know. Don't think it would be a fun ride at WOT.

So you bumped the throttle blades open slightly? :)

Traveller...Yes I bumped the throttle blades open slightly!!!

mcdoublehopper, remember the throttle body has a dual acting throttle cable. Look at it, it's not like a car. It has both retraction and on opposite side extention....to cables which enable you to pull the throttle shut as well as open. I feel comfortable.

I noted my TPS this morning was 101/24.

Good luck

I was being tongue in cheek. Note my earlier post... :) Cool you got it to work better.

Since the idle air is adjustable, that's what I was going to do to mine. Crack the blade a tiny bit, then adjust the air screw. The Dobeck took some of the light switch feeling away on mine, so I put it off.

Ah yes good point! would the 101% be the same as 99% so it wouldn't have to actually close to 100% before opening again? Not that familiar with throttle bodies.

Bike runs great with this throttle stop adjustment. Very smooth! I'm very happy now! The idle is higher though, which I like too.

I think this works because the Fuel Injector never really shuts off to exactly 0 with the throttle blade cracked slightly. It's as if you have a tiny bit of throttle on always, taking up the gap or slack if you will. The main fuel and air flow never goes to zero. So then when you give it a tiny bit of throttle, there is no lag because it is already injecting fuel. Now you have just given it more main circuit fuel and air, with no hesitation.

I really like the higher idle speed too. It stops the herky - jerky on/off throttle when just riding around town. Much nicer and smoother, like it should be. Like the old days with a Carburetor, only better and cleaner for sure now. Plus it is super off road climbing hills and also idling in parking lots. Lot smoother.

While I have no doubt this works, I just use the clutch to smooth the bike. I guess riding dirt bikes for years conditioned me to always use the clutch, no jerkiness.

I have found that inputting values to my PCV software in the 0% throttle cells was the nail in the coffin to my snatchy throttle.  I have the idle AFR set to 13.2 (0% throttle, 1500-1750 rpm) and the rest of the 0% cells from 2000-10000rpm set to +5.  This keeps the injectors open at all time except between 1500 and 1750, rpm ranges you would never be in during driving conditions and throttle operation.  These bikes seems sensitive to minor changes, so going from a good mix at mid throttle to zero fuel at zero throttle is very noticeable.  Damn emission regulations, choking out our little bikes...

Does this mod permanently raise the idle? Did you try lowering it with the idle adjustment on the left side of the FI throttle body?  I personally wouldn't ever run an idle above factory settings, but that's just because I see alot of red lights and traffic.  If the idle can sit at 1650 and you have cured the snatchy throttle with a simple tweak to the screw, which I believe does the same thing as adding fuel at 0% throttle, then this mod should be a sticky

just replace your stock throttle stop screw with an idle adjust cable like all stunters do for extra idle pull, even not stunting it comes in handy in tighter terrain, stock idle sucks when you let off the bike wants to dive hard and can easily cause you to lose balance when offroading. first mod ive done to all 3 of my wrx's is add an idle cable, may be why ive never understood what people are referring to with snatchy throttle. The on n off is caused by whats mentioned above, to low of idle and 0% fuel when let off. idle cable or idle stop screw adjustment hangs it open a little, problem resolved. Cable works far better for reasons above also, stop and go traffic you can run it lower anytime you want but when you want a little extra idle for offroad smoothness its a quick one turn away.

Note, with a high idle speed set at 2500 rpm or so as done above,  the Idle Speed Control Valve on the Throttle Body can be eliminated. It is not necessary when cold since the idle speed is already high enough.

To prevent it from increasing idle speed unnecessarily when cold, remove it and turn the nut on the end of it OUT about .100 inch.  This mimicks a Warm engine so it does not increase idle speed when cold.

This keeps the idle speed from getting to high when cold!


Have Picture

I re-tuned my bike's idle speed, using the following procedure to make it run smoother, just off idle.  

1. Set CO for best idle quality, with stock idle speed setup, because it does not adjust easily with a very high idle speed.

2. Eliminate the High Idle Speed Valve, since it is not needed.

3. Turn in plastic idle speed screw on side of Throttle Body all the way in, or off.

4. Turn in Throttle Body adjustment screw, under tank, about 1 1/4 turn in. (results in about 2400 idle speed)

5. Turn TPS Throttle Position Sensor until achieve a 24/104 setting. (Tried 21/100 was nearly the same result)

6. Start Bike, warm up, and test.

7. To achieve about a maximum warm idle speed of 2750 RPM , turn the plastic idle control speed screw on side of Throttle Body out about 1/8 turn of so. It is very touchy at this idle speed.  Note that with a high idle speed the idle drifts up and down easily, so that is why I use the Idle Speed Screw to adjust the final idle speed to 2750 RPM. (If you want to lower the idle speed a bit, you can just use the idle speed screw, rather than needing to remove fuel tank to adjust throttle blades.)

The motorcycle is much more enjoyable to ride with this setup for me. I like the smooth throttle at light applications. The higher idle speed, Throttle blade adjustment, and the TPS settings all contribute approx. 1/3 each to the improvements I roughly estimate.


Hope this helps others, Good Luck!

Picture of High Idle Control Valve on Throttle Body, removed on table.

The small screwdriver points to the nut to loosen about .100 to eliminate the cold high idle valve from increasing idle when cold.

The punch points to the plunger that advances out when the bike warms, or put in hot pan of water like was here.

Adjust this only if you have made the throttle blade idle rpm increase as stated earlier, since you do not need it if you already have a 2500 or so idle speed.
I did this with the fuel tank removed, when I adjusted the throttle blades.

Hope this helps, Good luck!

Your info just goes to show that I don't know everything, you're never too old to learn etc. You've solved my too-low idle issue. Ok, OK, I should've known, but sometimes you overlook things and overthink things.

Thanks for that, Liberty. I don't want an idle as high as yours, but I do want 1800-1900 rpm. Cheers mate.

Great to hear the higher idle speed is working for you! https://2img.net/u/2514/21/58/60/smiles/525406.gif

A 2000 RPM idle speed, rather than 2500 RPM is probably a good goal for most bikes.

(As the idle speed gets higher near 2500, it is smoother, though the bike tends to pull a bit at low speeds, which can be a trade-off)

Cheers!