More idle issues

Hi all,
Went for a long spin to the Antrim coast and GRiSO was not behaving very well. In fairness there had been
some clues beforehand namely the idle was intermittent at 1200 rpm and would occasionally idle at 2000 plus rpm
.Now the bike refuses to idle at 1200rpm unless I block the pipe from the air box to the stepper motor. I removed the
cars from the machine and cleaned them on the bench, a fair amount of mess was cleaned from them, but when put back
on the bike same issue. Reset tps using guzzi diagnosis and balanced carbs and then reset tps multiple times with no
improvement. I suspect the stepper is faulty and my question is ,
Is it possible to take apart the stepper?
to buy a replacement is fairly expensive and I followed a post about bypassing the stepper but would prefer
to repair what I have.
Thx in advance mark

Have a look here Tony looks like he got it sorted. [You must be registered and logged in to see this link.]

yeah confirm sorted - liquimoly carburetor and valve cleaner - about 10-15 ml into the stepper motor hose while idling, though not all at once. Several puffs of blue/white smoke, a stumble on idle and all should be golden.

If your bike is a flat tappet model it may be a sign the tappets are seriously worn too.

Well, if that solves it, then there was dirt inside. I know that some people put amounts of brake cleaner through the valve and that didn't solve it. I suspect not all problems will be solved this way.

Brake cleaner can be pretty savage on rubber parts, may cause more sticking than help ?

Stepper isn't maintainable from my ( unfortunate)experience. The shaft has a one direction 'barb' and you do damage pulling it out. Well I did.  I'd try Tony's nethod multiple times - the damn things are too expensive.
Conor

I remember someone who got it apart and back togheter

stepper is like this thing, the nose goes in and out and blocks the airflow.
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Thanks for all the replies, I tried multiple times with valve oil to get the valve to operate with no success.  Great picture of the valve , does anyone know if the valve  is normally closed or open at rest before the ignition is switched on as mine is permanently open all the time?
Might try removing the stepper from the bike again and soaking in a solvent

I have numerous sets of dead, fucked with, throttle bodies with steppers. PM me your address and I'll pop one in the mail. If it solves the problem you can pay for it. If not? Send it back.

Pete

Took pliers to my busted unit for you

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it looks like the unit is only pressed in? Is there something broken?, it looks like it can be put together.

looks like it, nose is scew on if im correct
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Great pictures and thanks for the great response. Ive tried to gently lever out the unit from the metal enclosure but it hasnt budged any tips on removing the motor from the housing without breaking any parts?

As you are finfing its hard yo get hold of inner body. Pulling on top connector risks ripping connector from the motor body. ( I know this...). That might be repairable if you are lucky but not for me. Need to be careful but a puff of compressed air in through one of the ports could help pop it...? Will experiment tonight on busted unit for you.

maybe heating the alu body with a paint stipper gently so it expands? Not to much so the plastic won't melt.

I tried air method - no luck

Sent Mark a pm with a very agricultural method that I got to work ok. Involves drilling holes in body so its a last ditch method.

At end of it all though there us still not much useful to be done once you open it up. If its not cleaning up with tony's method there is little more likely to be gained by opening it. If motor itself is the problem doubt much could be done with it.

Ok, this might sound drastic but i might try adjusting the yellow painted screw as the idle issue is back and im getting impatient. When i push gently the bar connecting the 2 throttle bodies the revs go down to an acceptable level and the screw appears to be a stop item. Any advice before i proceed.

thx in advance

Don't! Whatever you do don't touch that screw! Apart from anything else it won't achieve the desired effect because the stepper will simply compensate.

If you mess with the throttle stop screw the ECU can't gauge how much fuel to deliver, the system doesn't have a MAF sensor. You'll be up for new TB's.

Pete

Don't touch the sacred screw!

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Marktjoliver, DONT TOUCH THE STOP SCREW. How much vertical movement is there when you try to wriggle the throttle butterfly shafts at the underneath of the t/bs? When you had the t/bs off the bike I assume you looked through them. Was there a notable difference in the clearance around the butterflys? Any shiny spots in the t/b bores ? How much side to side movement in the linkage rod is there if you move it from left to right without moving the butterflys?

thx all, the screw will remain untouched. When i had the TB,s apart there was some shiny spots where the butterfly opens will remove again and check clearance and post photos. The linkage rod is ok with no undue play. Why do the revs drop when i push lightly on the linkage rod?

It affects it because you are pushing harder against the stop which :
- fractionally alters the TPS
- fractionally closes the throttle plates (like squeezing throttle closed)
- and probably wiggles the throttle plate in it's bearings which probably also do the 2 things above.

Photo time, there is some wear at the butterflys please advise if this is excessive.

thx mark[You must be registered and logged in to see this image.]" />" />" />" />" />

With the throttles shut how much vertical movement is there.? What do they look like when held up to the light with throttles shut?