This one DOES have me stumped..

[Huzo]

Gotta’ go now, watching this..
https://youtu.be/tcVmwf24zvU

[s1120]

Just a WAG but does the V85 have the same type of plugcaps as some other modern MG bikes that go bad a lot? I just thought that becouse you said it first acted up after washing.. 

[Huzo]

Just a WAG but does the V85 have the same type of plugcaps as some other modern MG bikes that go bad a lot? I just thought that becouse you said it first acted up after washing..

I have thought about that too and I don’t know.
The symptoms look a bit like it.

[Kiwi_Roy]

It is ride by wire isn't it, I know nothing about those systems.
Surely it can't be as complicated as a 1400 see Carl Allisons diagrams on This Old Tractor
A single throttle body I believe
I would expect it to at least throw up an error message if something was failing, even a humble V7 does that.

[smdl]

Back at the top of the page I asked if the ignition was single or dual plug on the V85
I wondered if the loss of a few HP could be one plug quitting for a second.
I have looked through all the reviews and none of them mention two plugs so I assume that is a red herring.

Sooner or later a question will come up about a wiring issue, so far I have not seen a wiring schematic for the V85.

Hi, Roy.

You can find the wiring schematic here:

http://www.thisoldtractor.com/moto_guzzi_small_blocks_wiring_diagrams_-very_large_and_easy_to_read-.html

Cheers,
Shaun

[malik]

..........l
I’m leaning towards TPS.
Is the TPS in the twist grip drum ?

On the 1TB's the TPS is somewhere up near the throttle body & ECU, might even be integral to something. Beetle knows. It's not as accessible as on the 2 throttle body bikes. FWIW, the 15RC ECU never showed any error code in Guzzidiag all the years I was having what turned out to be a malfunctioning TPS.

If the spark plug ends in a solid post, rather than being threaded, I would change out the caps & plugs. One of the first things I did to the 1TB V7. Nothing beats tactile feedback for reassurance of a solid connection down there.

[Guzzistaracing]

I'll go with that one.. but.. this is ringing little bells in my memory thingy. I think I've read of this somewhere else, too.

i was thinking the same, was it something about the traction control?

[Chuck in Indiana]

i was thinking the same, was it something about the traction control?

Seems like it, but my memory.. Oh look! Squirrel!

[Kiwi_Roy]

Hi, Roy.

You can find the wiring schematic here:

http://www.thisoldtractor.com/moto_guzzi_small_blocks_wiring_diagrams_-very_large_and_easy_to_read-.html

Cheers,
Shaun

I must be a bit dense, I dont see anything to download.

[smdl]

I must be a bit dense, I dont see anything to download.

Sorry, if you scroll down to the bottom of that page, the V85TT writing schematic is the last one listed.  You can just click on that and you will have the PDF.

Hope that helps.  I can send it to you directly if that doesn't work.

Cheers,
Shaun

[tris]

Could you jury rig an old school throttle lock and achieve the same cruising speed?

That should take any idiosyncrasies of the cruise control programming out of the equation

[Kiwi_Roy]

Sorry, if you scroll down to the bottom of that page, the V85TT writing schematic is the last one listed.  You can just click on that and you will have the PDF.

Hope that helps.  I can send it to you directly if that doesn't work.

Cheers,
Shaun

Of course it does, I told you I was a bit dense lol
Thankyou for that.

[smdl]

 

[mondtster]

Could it be when the ECU switches from closed loop to open loop or back the other way? That could easily produce a condition where the power droops slightly with seemingly no change.

[Huzo]

Could you jury rig an old school throttle lock and achieve the same cruising speed?

That should take any idiosyncrasies of the cruise control programming out of the equation

I have shut the cruise off and it makes no difference.

[Huzo]

i was thinking the same, was it something about the traction control?

Beetle was onto that from the start, but I don’t have a diagnosis yet..
If he can’t figure it, I can’t see that I’ve any chance.

[Huzo]

Could it be when the ECU switches from closed loop to open loop or back the other way? That could easily produce a condition where the power droops slightly with seemingly no change.

Will Guzzidiag show a code for that anomaly ?

[SIR REAL ED]

Huzo,

Is he ECU black?

Have you considered stripping the black paint off it, then polishing it or painting it silver?

Can't hurt.

You might pissed off the Italian gods of motorcycle styling with your arrogant modifications of their divine design!

If it is a subtle surge, you might want to swap out your plug caps, maybe try iridium plugs, or go a heat range or two hotter just to see if there are any noticeable difference.  That would at least be a clue as ignition as a potential source.

How about the dry gas, have you tried that yet?

cheers mate!

[lucky phil]

Could it be when the ECU switches from closed loop to open loop or back the other way? That could easily produce a condition where the power droops slightly with seemingly no change.

Hence my suggestion to use guzzidiag to switch off the closed loop and see the result. Closed loops effect is on steady state throttle and is effectively a rich/lean switch. Common for all sorts of engines to surge a little in the switching if the mapping isn't great.

Ciao

[Huzo]

Huzo,

Is he ECU black?

Have you considered stripping the black paint off it, then polishing it or painting it silver?

Can't hurt.

You might pissed off the Italian gods of motorcycle styling with your arrogant modifications of their divine design!

If it is a subtle surge, you might want to swap out your plug caps, maybe try iridium plugs, or go a heat range or two hotter just to see if there are any noticeable difference.  That would at least be a clue as ignition as a potential source.

How about the dry gas, have you tried that yet?

cheers mate!

That is actually very funny SRE.
I pulled the plug leads off (lucky buggers... ) while riding at high speed and the surging stopped...!
I think you are onto something...
Also I reject the notion that I am arrogant, I’m just wiser, more intelligent, funnier, better looking and generally superior to everyone else..
How can that possibly be my fault...?

[drbone641]

Could it be an injector
issue with turbulence in the fuel flow? During basically constant higher RPM

[mondtster]

Will Guzzidiag show a code for that anomaly ?

It’s not an anomaly. But if the target AFR changes significantly while switching modes it would have the potential to cause a detectable increase or decrease in power.

[Huzo]

It’s not an anomaly. But if the target AFR changes significantly while switching modes it would have the potential to cause a detectable increase or decrease in power.

Hey, there’s another thing..!
I thought to isolate the TC so selected off road mode. Sure  enough, the bike could be made to spin the wheel under acceleration.
There seemed to be no discernible loss in power though, I thought it was supposed to de rate the output a bit..
Fancy that..!

[mondtster]

Hey, there’s another thing..!
I thought to isolate the TC so selected off road mode. Sure  enough, the bike could be made to spin the wheel under acceleration.
There seemed to be no discernible loss in power though, I thought it was supposed to de rate the output a bit..
Fancy that..!

I can’t tell a difference in power delivery no matter what mode I’m in either. From what I recall seeing when I looked at the engine calibration file, the requested torque is the same for all three modes. But I haven’t looked at the file since last fall so my memory may have failed me.

Another thing I had thought of is that you changed the exhaust and relocated the o2 sensors. I wouldn’t expect this to cause trouble but maybe? Did it run any different before vs after the exhaust modification?

[SIR REAL ED]

Huzo,

this is a single TB bike right?  So it can't be a balance issue, right?

Might want to consider replacing the TB with a carb to see if that helps!   

[Huzo]

Huzo,

this is a single TB bike right?  So it can't be a balance issue, right?

Might want to consider replacing the TB with a carb to see if that helps!   

I did it the other way ‘round Ed.
I took the throttle body and associated circuitry, along with the ECU and grafted it all onto my lawn mower while having a coffee. The darn thing ran perfectly...!

[Huzo]

Another thing I had thought of is that you changed the exhaust and relocated the o2 sensors. I wouldn’t expect this to cause trouble but maybe? Did it run any different before vs after the exhaust modification?

It never did it on the standard system and I’m thinking to throw that back on to try it again.
Bear in mind however,  it doesn’t do anything wrong 95% of the time with the new one..

[mondtster]

It never did it on the standard system and I’m thinking to throw that back on to try it again.
Bear in mind however,  it doesn’t do anything wrong 95% of the time with the new one..

Interesting. If you do put the old exhaust on again let us know the results.

Assuming we’re heading down the right path, the ultimate solution may be to get an ECU calibration that has the closed loop function disabled. I know it was being worked on at one point in time but I’m not sure where the experts are at on that project.

[SIR REAL ED]

I did it the other way ‘round Ed.
I took the throttle body and associated circuitry, along with the ECU and grafted it all onto my lawn mower while having a coffee. The darn thing ran perfectly...!

Makes sense.  The engine on the lawn mower was probably designed 30 years after the engine on the Guzzi....

did you try the dry gas, or switching fuel yet?  How about a new set of plugs?  Sometimes it's the simple things.......   

[Huzo]

  How about a new set of plugs?  Sometimes it's the simple things.......   

Not yet but I will.
Problem there is that it feels like a partial loss and so intermittent.