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A simple method for Idle speed adjustment?


NakedV
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Hi All. Fitted the Mistrals over the W/end and put 170 miles on the bike. several plug checks later and all looks pretty good. Bike running very nice with no flat spots and strangely feels a little smoother. (It's a smooth bike anyway). My only niggle is that the idle speed has come up a little to about 12-1300 rpm. Is there a simple way to drop the revs at idle without upsetting the entire set up?

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The simple solution is to turn both idle set screws out the same exact number of turns.

Whatever you do, count the precise number of turns so you can undo what you did.

You probably only need to go about a quarter turn out.

But I recommend you should check the balance and check the TPS reading.

Buying something to measure balance is not that expensive and once you have it, it is very quick and easy to check the balance....but setting it can take more effort.

I also recommend splicing in connectors to read the TPS (but this could invalidate your warranty)

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My only niggle is that the idle speed has come up a little to about 12-1300 rpm.

 

I think I have read here in the past that many members have their idles as high as 12-1250 rpm's saying it helped idle cut-outs etc. Mine is set and normally reads 1,800-2,200 rpm's FWIW.

 

I agree to check the TPS as it should be on or near 3.6.

 

Bob

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.... Just leave it as it is. ...

 

Exactly. Don't splice in anything, don't check here and there this or that. You say it's running smoothly. In this case the only thing to check regularly is fuel and tire pressure. Maybe also the oil level, but then it's enough.

 

Anyway, turning out the right idle stop screw a little (after you've finally found and recognised it) is nothing you need to document in every detail.

 

Hubert

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Anyway, turning out the right idle stop screw a little (after you've finally found and recognised it) is nothing you need to document in every detail.

 

Hubert

 

That is a pretty cavalier statement suggesting just turning screws willy-nilly. :D

I'm always sure to have a notebook, photographer, and notary public present to notate, document and notarize any adjustments.

Can't be too careful :whistle:

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For sure, even with any changes you make, use the pinned TPS Procedure. All the values remain the same.

 

I've said this before, but it's not uncommon that the early tachs read "optimistically" and a 1200 rpm reading could really be 900 (not high enough). Coming from a big block V-8 background, I've always loved the cam-lope idle, but the Guzzi (for several reasons) likes it higher.

 

Just winding one or both of the idle screws is not a good idea. Not disastrous, mind you, just not good.

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Bloody, Hell! It's starting to make sense. Correct me if I'm wrong but the 150 mV setting, all closed is a static base line. The ECU I take it uses this as a reference point from which it then adds the required increase in fuel corresponding to the increase in voltage-throttle opening from this "base line" setting. One this "base line is correct it's just a case of balancing both sides like with carb's. Simples :drink::drink::drink: Mick. (Not thick really, just want to be clear before the tools come out).

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Bloody, Hell! It's starting to make sense. Correct me if I'm wrong but the 150 mV setting, all closed is a static base line. The ECU I take it uses this as a reference point from which it then adds the required increase in fuel( and ignition timing) corresponding to the increase in voltage-throttle opening from this "base line" setting. One this "base line is correct it's just a case of balancing both sides like with carb's.(Yes, but... injection bodies adjustment screws are not like carbs mixture/idle screws) Simples :drink::drink::drink: Mick. (Not thick really, just want to be clear before the tools come out).

:thumbsup:

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....

Just winding one or both of the idle screws is not a good idea. Not disastrous, mind you, just not good.

 

There's no reason to say this. What you say is wrong. Turning the idle screws, or in other words, adjusting the idle revs to one's personal gusto, is exactly the same as pulling in the idle lever, just in the opposite direction. It has nothing to do with balance, synchronousity or TPS base settings.

 

It may be not a good idea to have the idle set to too low revs, but again, this is a different thing than just turning the stop screws out or in.

 

Hubert

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Bloody, Hell! It's starting to make sense. Correct me if I'm wrong but the 150 mV setting, all closed is a static base line. The ECU I take it uses this as a reference point from which it then adds the required increase in fuel corresponding to the increase in voltage-throttle opening from this "base line" setting. One this "base line is correct it's just a case of balancing both sides like with carb's. Simples :drink::drink::drink: Mick. (Not thick really, just want to be clear before the tools come out).

Once the 150mV baseline is correct, its just a case of balancing AND getting idle speed correct AND TPS reading correct AND CO reading correct.

Correct TPS reading, and Veglia idle speed vary by bike.

According to documentation at http://www.mphcycles.com/Technical/tpsexcel3.htm the ECU recognizes anything below 575mV to be at idle, as seen by flag on diagnostic program.

The ECU never sees the 150mV during normal operation. The 150 mV is measured when throttle linkage is disconnected. When throttle linkage is connected the TPS will be about 500mV (give or take about 75mV) and should be what the ECU sees at idle.

Theoretically if you disconnect the linkage and set screws and move the right TB valve from fully closed to fully open the voltage should go from 150mV when fully closed to just under 5V at WOT (wide open throttle) (4.85V might be a typical reading, but it should probably be between 4.75 and 4.95V)

A few on the forum could not get the engine to run right when using the 150mV setting. Instead they used a recommended mV at idle and got good results.

Either way should work if done correctly.

Also, I find that at 1300 RPM the transmission clunks when shifting from neutral to first. If yours shifts smoothly than you are probably fine at that RPM reading. In any case you want to keep idle RPMs well above the stalling point, but below the transmission clunking point and below 575mV (4 degrees as read by diagnostic software)

The speedometers on our bikes are not all calibrated the same. Being off by 200 rpms or more seems to be common.

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I've said this before, but it's not uncommon that the early tachs read "optimistically" and a 1200 rpm reading could really be 900 (not high enough).

 

 

FWIW - I have a VDST (scan tool) and have experienced this..........My vaguelia is just not that accurate! Look, she starts at 750 rpm's!

 

Bob

tach.JPG

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Quick hijack.

Bob,

 

Those mirrors, Rizoma Dynamic? How is the view? I'm considering them for my Aprilia but am worried about the small size.

 

Thanks, back to idle adjustment now.

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Those mirrors, Rizoma Dynamic?

 

Yes Dan, Rizoma Dynamic mirrors. Funny........the Mickey Mouse ears are MUCH larger but vibrate so much on my bike you couldn't see anything......the Rizoma's are smaller but for whatever reason, do not vibrate so I can see. It only took me a couple days to get use to the size difference.

 

BAck when I bought PJ's was the only guy......seem to be more carriers in the states now.

 

Bob

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