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sirthumpalot

The TPS adjustment thread

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Posted (edited)
14 hours ago, sirthumpalot said:

It would be unusual for your tps adjustment to cause the idle to rise that much.  Double check that you didn't accidentally activate the cold start knob as that will make the idle rise up a lot.   Let us know what you find.   

The only thing I can think of is that when i rotated the TPS unit to remove the cover, I created a vacuum leak.  The install of the clutch was methodical and error-free.  Idling to reach warm up was fine and normal.  It was only when I was bliping the throttle to break in the clutch it started rising.  Now that Im thinking about it, I wonder if I bound up the throttle cables a tiny bit when putting the tank back on after installing the TPS.  

Edit- 

Definitively throttle cable binding

Edited by N.dica

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Posted (edited)

If it's easier than removing the tank for you, put the TPSTool back on and take a TPS reading at idle.  If it's where you set it, then the cables are not binding.  If it's higher than where you set it, then something is holding the throttle open, whether it be a bound cable, the cold start or idle setting.  If you want to eliminate the TPS adjustment from the equation, temporarily set the TPS back to the stock setting and see if that resolves the issue.  Here is some info on the cold start knob, it should be popped-out during normal operation.  Pushing it in will raise the idle: 

https://dirtbiketest.com/fresh-dirt/ktm-throttle-body-tuning/#66FUJGChVjk6qIeB.97

 

Edited by sirthumpalot

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Been noticing some slight lean bog when I wack the throttle hard from idle and light backfiring while in the air as I back off the throttle with the engine unloaded.

So I bumped mine up pretty significantly by .12v to .68v from .56v.  The bike seems  to idle with MUCH more authority and feels more like a 450 in the lower mid range.....wack the throttle and it barks like an angry beast ha ha.

 

C2ED71C1-4219-4524-A40F-04733227D278.thumb.jpeg.7a74421fac3d4bbb09d2a077ba98e60a.jpeg

 

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Maybe someone could help me.

 

I bought a used 2017 250 exc-f, and I should have left well enough alone because it ran fine but... I took the reeds out of the airbox and now when I crack the throttle from idle I get a pop and stall.

So I bought the TPS tool and turned tps to .69 and I am still getting the pop and stall

 

Any ideas? The bike was de smogged already when I bought it.

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Where was the TPS when you started?  Feedback I get from the 250 guys indicates they usually get the best results with higher settings than the bigger bikes.  Try jumping to .74 and see what happens.  

Also does it stay running if you do more than crack it?  Even when things are really lean, it's rare to completely stall, which makes me think there might be a second issue.  

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9 minutes ago, sirthumpalot said:

Where was the TPS when you started?  Feedback I get from the 250 guys indicates they usually get the best results with higher settings than the bigger bikes.  Try jumping to .74 and see what happens.  

Also does it stay running if you do more than crack it?  Even when things are really lean, it's rare to completely stall, which makes me think there might be a second issue.  

Yes, If I slowly open the throttle it will stay running, It just stalls if I really crack it quickly

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1 hour ago, surfnjmatt said:

does anyone happen to know what the stock euro tps settings are?

I'm not as familiar with the 250's, but there are 2 common factory defaults depending on which style throttle body you have, most likely your bike falls into one of these two.  Put the TPSTool on and give the idle screw a little turn, like 1/8.  If the TPS reading changes then your factory default is most likely 0.40V with the idle all the way out (throttle plate fully closed).  If adjusting the idle does not affect the TPS reading at all, then your factory default is likely 0.60V and it does not matter what the idle is set to when you reset the TPS.  

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53 minutes ago, sirthumpalot said:

I'm not as familiar with the 250's, but there are 2 common factory defaults depending on which style throttle body you have, most likely your bike falls into one of these two.  Put the TPSTool on and give the idle screw a little turn, like 1/8.  If the TPS reading changes then your factory default is most likely 0.40V with the idle all the way out (throttle plate fully closed).  If adjusting the idle does not affect the TPS reading at all, then your factory default is likely 0.60V and it does not matter what the idle is set to when you reset the TPS.  

Ok so I adjusted tps to .74 and the Popping and stall is gone, but now it does bog off idle if you crack it real hard.. Other then that its like a new bike.. Just want to be sure I am not still lean as I don't want to get to hot

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Just now, Fatt_Tones said:

 

Is the bike fully warmed up when you have this bog upon whacking open the throttle from idle?

No it is not

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Just now, Fatt_Tones said:

 

Maybe before adjusting the TPS again, let the bike warm up to proper operating temp and ride it.  Sounds like you're getting close. 

 

IS the Bog a sign of being to rich or too lean?

 

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If the bike is cold when you're testing it, then most likely the bog is from being too lean.  As mentioned above, definitely get the bike up to temp before judging the result.  It's not unusual for a cold 4-stroke to act lean.  

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55 minutes ago, sirthumpalot said:

If the bike is cold when you're testing it, then most likely the bog is from being too lean.  As mentioned above, definitely get the bike up to temp before judging the result.  It's not unusual for a cold 4-stroke to act lean.  

Ok, that seemed to do the trick.. Once warm the bog was gone..

 

So this means I should be running a good, mix? Just weary of running to lean

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