Clutch Rattle / Idle Balance GRiSO 1100

I commented that my clutch was rattling on a different thread, I can't find it now but Pete responded it might be idle balance.
Sure enough when I checked today the balance was way out, so bad it would have sucked the oil out of my U tube manometer at idle.
The last time I did a balance about a year ago it was within an inch or two with both air bleeds closed, I'm not sure what's changed in the meantime. Both air bleeds were still closed.
To the best of my knowledge the sacred screw has never been tampered with, the bike has been off the road for 6 months.
So when I turn the bell crank about 10 turns it somewhat balances but by this stage the motor is doing around 3,000 and the LH body is still on the stop, obviously the RH is quite a bit open. I believe the stepper motor is working at least it runs about 2000 revs after a start then comes back to ~1,500
I just cannot get it to balance.
In the meantime I tweaked the bell crank and air bypass of RH listening to the clutch rattle, its currently running quite a bit quieter.
The bike seems to be running well.
I haven't reset the TPS yet, I don't see the need until I get the balance right.
Any thoughts would be appreciated.

Use the bell crank to balance at 3000 RPM, then reset the TPS, then balance idle with air bleeds.

Run a compression test. If it was fine a year ago, nothing has been touched and now it's off so far you need to turn the bell crank multiple turns there is something very wrong.

Have you checked the valves, (Have those gaskets arrived yet?) if you've got a tight or burnt one that could cause it. My guess is the rough clanky idle is down to it only running on one cylinder at idle.

No not arrived yet, thanks for the suggestion on where to look. I will do a compression test ASAP
Check the valves before riding it again.
One little thing, when I checked the valve cover screws several were so loose you could have just about wound them out with your fingers, I just assumed the material had shrunk.
As I said I wound on the bell crank and opened RH air bleed for the moment, it quieted down significantly.
I didn't run it for a whole year up until 2 weeks back, no reason other than cost of insurance.

Just a quick question of anyone.
Compression test, is that something you can do on a cold motor or should it be warmed up?
I know to open the throttle wide, I will do it with the bike vertical, not on the side stand.

For what you want to know it won't really matter. Make sure you disconnect the coils and injectors before doing the test. If you leave theM connected the moment you spin the motor it'll fire up, your gauge won't like that!

A good point, just pulling the outside plugs won't stop the inside ones from firing.
The wire to the solenoid runs right by the positive battery post, I can spin the starter with the key out.
Update:
I checked compression this morning, both cylinders were a touch over 180# so I know it's nothing serious, just a screw loose in the driver.
I will do the electronic TPS reset where its at now and try again, also look to make sure there are no hoses dropped off, I'm sure its something stupid.

So I pulled the tank off to see if a hose had become disconnected, all ok
I found by opening the air bleed on RH body 3 full turns it will almost balance but the revs are up, the RH still has a stronger vacuum but not over the top.
I'm starting to wonder if I don't have an air leak into the LH body, I will check that out next.

Time for an update, I took the throttle bodies off and gave them a good scrub while I used them to test a theory on measuring the flow rate through sacred screw setting.
When I put them back the engine was idling too fast but I think that's now resolved. One thing for sure now its balanced the clutch rattle is much reduced, thanks Pete.
One thing, when you adjust the throttle cables is it best to leave a little backlash or should the open and close cables be adjusted with no slack?

The smallest amount of free play you can get away with without the engine speed rising as you turn the bars lock to lock.

Thanks Pete

Well The clutch rattle seems to be resolved but I gtill have the annoying high idle speed driving me nuts.
I went away on a two day camping trip, On the way I found that at times the engine was idling at nearly 3000 revs, it seems unpredictable and made it a pig to ride, you couldn't rely on engine breaking.
One thing I determined if you pull up with the clutch pulled in say it is idling at 2500, if you blip the throttle it might come down to 1500 but then after a few seconds the speed would ramp up again over about 5 seconds.
I pulled off the inlet manifolds to inspect the "O" rings, checked the rubber couplings, Replaced the rubber couplings on the stepper motor.
Finally out of desperation I pulled the stepper motor supply hose off the Air-box and jammed a stick in it all to no avail.
BTW the sacred screw has never been tweaked.
One air bleed closed the other less than 1 turn open.
No faults showing on Guzzidiag
The twist grip is fully closing the throttle, it's hard on the stop.
Anyone have any suggestions.
Thanks
Roy

Take the TB's off and give them a really good scrubbing. You will probably find that grime on the butterflies and in the ports combined with a bit of wear in the spindle bushes means that when you shut the throttle with the engine off and do a TPS re-set it will happily recalibrate to 4.6 but when you start the engine and move the throttle, when it closes the combination of grime and wear means that the butterflies won't close properly and if you look at the TPS value in the live data in Guzzidiag you'll find that the TPS value has *Risen* by an amount, maybe as much as to 5.1 or so degrees.

The thing is at that sort of throttle interpretation the spark is beginning to advance and consequently the engine speed increases!

So, my course of action in cases like these is to clean everything thoroughly and then perform a balance and TPS re-set. If this fails to rectify the situation you can try the 'Nasty Kludge' of recalibrating the TPS while holding the throttle slightly open by sticking a 2-4 thou feeler gauge between the stop screw and the spindle stop. This will mean that after the re-set is completed the TPS value will be too low, but, when the engine is started and the manifold vacuum pulls the butterflies around a bit wider open. This will increase the value back up to roughly where it should be and the spark will not advance and the idle will remain stable, where it should be, controlled by the stepper.

Stepper starting to frizz - has happened to a few bikes of similar vintage. My stepper is now blocked off and no longer any issues with high idle. I put an 8mm (I think) bolt in the end of the stepper hose to block it off. Even in winter, no issues.

So I reset the TPS using a 0.1 mm feeler this gave me a reading of 4.2 degrees, Initially it seemed to run better but it soon settled back into revving its head off. At one time it was spinning at 3,000 revs with the LH throttle jammed to the idle stop.
One thing I should have mentioned its started to pop back in the exhaust, could that be a symptom of a leak?

I checked the throttle balance, its right on at 1500 and 3000 revs, no air bleed open at the moment.
The stepper motor is restored, at times it will idle around 1100 then a short while later might be 3,000

try just blocking the stepper motor inlet and see if the idle is normal. If it is, then the stepper is sus. You can put in some carb cleaner and it may help, but long term, it is toast. If not the stepper, other have/will chime back in.

Do one thing at a time Roy, start with the easy ones...

Oz1200Guzzi wrote:

try just blocking the stepper motor inlet and see if the idle is normal. If it is, then the stepper is sus. You can put in some carb cleaner and it may help, but long term, it is toast. If not the stepper, other have/will chime back in.

Do one thing at a time Roy, start with the easy ones...

Yes I tried that on day 2 of the trip, pulled the hose off the air box and plugged it with a stick.
It's back on the air box now.

Have you pulled the TB's and given them a really good cleaning? How's the TPS signal?

Less than 500 km ago I scrubbed them both with Acetone. I did not use it on the coupling rubbers just scrubbed it through the butterfly area on a rag to remove the carbon built up.

Re the TPS signal I have only looked at it with Guzzidiag and its sitting at 4.2% at the moment using the 0.004 (0.1mm) feeler. Seems very smooth up and back with throttle.
If I were to connect the multimeter to it I assume its not to set it like an earlier era bike just to watch it.

Did you have them off, 'on the bench' off Roy? Doing them in-situ doesn't give you good enough access for a really good 'Deep Clean' as we have been taught to say in these covidian times.

Kiwi_Roy wrote:

Re the TPS signal I have only looked at it with Guzzidiag and its sitting at 4.2% at the moment using the 0.004 (0.1mm) feeler. Seems very smooth up and back with throttle.
If I were to connect the multimeter to it I assume its not to set it like an earlier era bike just to watch it.

What does GuzziDiag show for the Throttle without the feeler gauge? The multimeter would be a good test to confirm the TPS isn't noisy.

Pete,
      Yes I had them off on the bench, I cleaned them with a rag soaked in Acetone all the throat but didn't swab out the air bleed.

Beetle,
         It would show 4.6 without the feeler, I didn't see the creaping up that Peter referred to, this bike is at about 60,000 km

I thought I would monitor the TPS Voltage to see if anything showed up there, I used a sewing pin to tap into pin C of the connector, I didn't use another pin for negative but connected the meter to a tappet cover bolt as chassis.
Key On I got 478 mV
With the motor running I got about 531 i'm not sure why but I notice the 0 Volt reference for the pot does come from the ECU not chassis
The mV ramped up to about 4 Volts very smoothly however after a while the idle started to wander.
Allowing the motor to idle after a while it went from 1100 - 1500 - 1700 while the TPS stayed firmly at 531 mV

Heres something new, I suddenly got a red triangle and SERVICE message
The stored faults in Guzzidiag were
P0130 to low  I wish this version of Guzzidiag had a list of the messages
P0120 to high
The service message went away but later came back with just P0130 to low

Note: my version of Guzzidiag V0.47 is the only one I could get to run on this ancient Mac
I really must update to a better platform this version crashes regularly.

P0120 is TPS open circuit or short to neg/pos. A very helpful error.

P0130 is lambda probe short to positive.

Sounds like the TPS may be taking a dump.

What might be worth doing is picking up a set of second hand TB's, they come up pretty often on the Bay of Fleas and either swap them out holus bolus Or swapping the TPS and then the stepper as a process of elimination. A second hand set will almost certainly be cheaper than a new TPS or Stepper.

Thank you Gentlemen,
So I assume the early Norge throttle bodies are the same as the GRiSO or is there a particular one I should ask for.
Thanks
Roy