Surging/stumbling 1999 Bassa

[marcmorrison]

Need some help/clues/ideas to rid my Bassa of surging/stumbling....here's some background info.
Just purchased from original owner with 7,300 miles...all stock components.  I have changed all fluids, oil/air/fuel filters, new spark plugs, wires/connectors, valves set cold to 6 at intake, 8 at exhaust.  Checked TPS...no gaps in the sweep from 0 to 5 volts.  Fresh full tank of premium fuel...condition of pre-existing fuel unknown???  Seafoam has been added to the last full tank of gas...haven't ridden enough since then to determine if that will change anything.

Problem is hard to start....stumbling, rough from idle speed to about 2,000 rpm....surging at this approximate throttle position when riding.  Once things get beyond 2,000 rpm, it's smooth and strong to the higher rpm's.  My first thought was TPS, but it shows no gaps and is set correctly.  Are there other sensors that would come into play under these conditions (I'm a points/condensor/carb kind of guy)???  Maybe throttle plates are out of balance/synch....symptoms strike me more as a fuel delivery as opposed to an electric issue (of course, that would include the ECM and other attached/related components)???

BTW, these issues were present when I picked it up two weeks ago, so I haven't done anything yet to either cure it or make it worse.

Thanks in advance for your help.

[Chuck in Indiana]

Ok, I'll start it off. You say you checked the sweep of the TPS, but did you check it was a 150mv, linkage unhooked, etc.?

[marcmorrison]

No...I failed to unhinge the linkage...will do so and report back.  I set the TPS at the same voltage as my 75th MG (also, unhinged when I checked it).  Thanks for the lead!!

[guzzisteve]

I'll bite too, Clean the throttle bodies, take out air screw and clean passageways. 20 year old goo cleaned off.
I always back off idle screw and check TPS, no short cuts.
Hell, it could be your sidestand switch being rusty.

[fotoguzzi]

yeah base line TPS setting first thing coming to my mind.

then the fuel trim setting out of whack? you need Guzzidiag or techno research tool to adjust that.
 
OH but super cool you got a Bassa with low miles! what color?

[marcmorrison]

Chuck....I disconnected the throttle linkage and reset the TPS to 154.....still bucking at idle (almost to the point of dying), surging/stumbling to about 2K rpm.  Suggestions, ideas, thoughts, etc???

[fotoguzzi]

It's been a long time but if I reach into a fold in my brain I remember you set the baseline voltage to the 154mv but then increase it to something like 450 with the idle stop screw? so what procedure are you using to set the TPS?

found this from V11LeMans.com

The consensus has been to set the idle where the bike simply idles well without concern for the "degrees of opening" or millivoltage exhibited by the TPS. This is in Step 6 of the Decent Tune-up.

Also, note that the TPS idle setting is a range while the baseline is specific.

Just to clarify, the fully closed "Baseline" TPS voltage, measured with a quality voltmeter is 157 mV (Meinolf's derivation).  :nerd:

 Guzzidiag can't perform that task and it helps mightily to use the Casper's TPS Breakout Harness.

The idle TPS voltage of around 530mV is not critical. At that point, where ever it ends up is fine. :rasta:

Our respected friend. Meinolf, agrees:

"The value after reconnecting the linkage doesn't have to be 525mV. It can be 500 or 400mV. The ECU will interpolate anyway (unless you follow below procedure, then your idle setting is exactly at a break point). Set it so the specific bike idles best."
One of the least considered factors in the run quality of the V11 is the battery condition, high current relays, and clean/ solid/ treated electrical connections and ground (earthing) paths.

NOTE: this for a V11 Lemans, numbers might be slightly different but what I'm saying is your 150ish voltage is with butterfly fully closed not what it should be at idle.

[marcmorrison]

I'll take a look at the throttle bodies tomorrow and give things a good cleaning.  As far as the sidestand switch, it has obviously been removed by the prior owner....can't even find the wire leads from the switch (must have been cut back, hid somewhere...hopeful ly looped anyway). Will check on that possibility as well.  Thanks....keep swinging!!

[oldbike54]

 7,300 miles , if that is correct that is about the mileage that the valves are bedded in . Check the valve lash .

 Dusty

[marcmorrison]

Valve lash was checked cold....not off by much, but intake set at 6 and exhaust at 8.

[guzzisteve]

Wires for the sidestand switch run up the LH frame tube to main harness under tank. Just being unplugged works fine.
Have you looked into the electric fuel petcock, could not be opening fully OR a rat nest in the airbox or exhaust

[rodekyll]

What ECU?

If it's the big one under the seat there should be an idle trim adjuster.  I forget where.   Have you tried to use it?

If it's the later, small type it can be trimmed and troubleshot with guzzidiag and the error codes can be read.

IIRC, either type should be able to blink out diagnostic codes, too.  My EV has a red LED for that.  I've not read it in so long that I don't remember how.

But I'll suggest it's possibly a leaky or misrouted plug wire, bad connection to the coil or plug cap, or other high resistance generator, like a combination of resistor wires, resistor caps, and resistor plugs.

  The old points system in my Convert with 7mm wires acted like that when the spark was bleeding off and grounding to whatever was handy -- often my leg, if it was wet out.  Then around 2k or so everything seemed normal.  Either my leg got numb or it really did smooth out.  At night I could see the light show and jump Sparks to the engine with a screwdriver.  When that happened I would trim the wire back a few mm and reattach the cap.  I've solved it forever by running the wires through plastic tubing.

The point is that since you just replaced all that stuff, it wouldn't hurt to review your wire routes, overall resistance, connections, and plug gaps.

[John Ulrich]

Bassa’s were the first to get the 15m CPU.  I had mine remapped by an Aussie Company, FIM, that remapped Ducati’s using the 15m.  I have not heard of anyone else who cracked the codes to do this.

[rodekyll]

It's been done for a while now.  Guzzidiag for the little stuff and Beetle here on the board will remap a 15m if you don't want to.  Software is free.

[Zoom Zoom]

Lots of good replies already, but I do have something to add. Firstly, 6 and 8 is a bit much. Original US spec was 2 and 4. Euro spec was 4 and 6, which works well. (edit: The measurements are in thousandths, just to clarify.)

Anyway, probably not your source of trouble but worth mentioning.

Someone also mentioned the plug wires. I was experiencing trouble with my EV back when. What I discovered was the plug wires were trapped in the cooling fins where they came around the back of the jug, and discovered that was causing me grief. I took an old piece of fuel line, sliced it lengthwise, and slipped it over the plug wire with a small clamp to hold it in place. Although I was ready to get a new set of wires, That solved my trouble so I called it good.

Just out of curiosity, is the bike equipped with a Power Commander? I had one for a while and it messed up once while away on a trip. It made the bike run rich and it was a PITA at low rpm's kind of like you are describing. I unplugged it and the bike started and ran fine at low rpm's. I never reconnected it after that.

John Henry

[Wayne Orwig]

Have you cleaned the tips of the timing sensors?
New plugs?

[John A]

My prediction is this will take a software cure to fix. Btdt, same as JU. Bassa's had that problem and if it's never been done, all the other stuff helps but you'll need Beetles magic, along with GuzziDiag. I don't think FIM is still in business, that's what JU and I used so many years ago.

[Sheepdog]

The low speed surging suggests fuel trim to me, also.

[Kiwi_Roy]

Valve lash was checked cold....not off by much, but intake set at 6 and exhaust at 8.

As others have stated the setting of 154 or 157 with the throttle fully closed is the important one in fact you can skip the next one and just set the idle speed with the fast idle lever or throttle stop and never know what the millivolts is.
It could be your ECU resetting, monitor the 12 Volts at the ECU relay coil with a small lamp, if you still have the electric petcock the fuse for it is a good point to access the relay coil.  I’m thinking that at such a low mileage it’s more likely to be something in that circuit. The lamp should never so much as flicker.
Why did you replace the plug leads?
To check them just pull the caps off both plugs and measure the resistance to chassis, both sides should be the same, about 8k (this checks resistor cap, lead and coil all together)



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[oldbike54]

 Do all Bassas run the 15 M , RK and I just had this discussion . Clarify please .

 Dusty

[fotoguzzi]

Do all Bassas run the 15 M , RK and I just had this discussion . Clarify please .

 Dusty

yes the 95-96 or 97if there was one? Cal 1100ie and 98 -00 EV had the big box, "99 Bassa and V11 got the 5m. then sometime around 2000-01 the EV got it.. about the same time the EV got the body makeover maybe?

[rodekyll]

Dusty, they seem to be making a distinction between an EV and a Bassa.  I didn't know that the two models were concurrent.

[marcmorrison]

To answer some of the questions/scenarios mentioned to this date.  The prior owner mentioned that he attempted to hook up the Power Commander, but for reasons unstated, he was not happy with the results and removed it....what else he may have done to COMPEL the PC to work (ECU, throttle settings, etc.) also unknown.  As previously stated, this problem existed at the time I test drove the bike....everything I have done to date since acquiring the bike could be described as general (or preventive, in the case of plugs, wires, connectors) maintenance, however, none of those things has done anything to alleviate the problem.

Question....1) where is the timing sensor located??  2) how can error codes in the ECU (by way of the red led light) be displayed???

[Kiwi_Roy]

If you were to look from in front of the engine it's at the top of the timing cover at 2:00 It picks up the teeth of the sonic wheel fixed to the cam shaft behind the chain sprocket.
The gap between sensor and wheel is set by shims. (I think it's ~ 1mm on these engines)
Sometimes an owner will remove the sensor to fix the oil leak and get the gap wrong.

I find the best way to measure the gap is to put a blob of JB Quick on the tip of the sensor, install it, wait 10 minutes then remove it to measure the thickness of the JB blob. It won't stick to the wheel because it's oily but don't rotate the engine while waiting for it to set up.

There's a lot of discussion as to which ECU you have, it would help to know that
Have you located the warning lamp, I believe it only flashes a code while the ignition is On (I never got the one on my EV to work)

[oldbike54]

yes the 95-96 or 97if there was one? Cal 1100ie and 98 -00 EV had the big box, "99 Bassa and V11 got the 5m. then sometime around 2000-01 the EV got it.. about the same time the EV got the body makeover maybe?

 Pretty sure the 2,000 model year got the 15 , at least the Jackals did .

 

Dusty, they seem to be making a distinction between an EV and a Bassa.  I didn't know that the two models were concurrent.

 I'm not disagreeing with any of this , but memory says we have had this discussion before and some of the earliest Bassa models had the 8 . Just seeking clarification .

 Of course we are dealing with Moto Guzzi , so ....

 Dusty

[marcmorrison]

I located the timing sensor...removed, cleaned a little oil off, polished a small amount of "crud" from the center electrode, re-inserted with the original shims....good to do this anyway, but surge/stumbling still present.  Checked the new plug wires, connectors....5K ohms as specified. YES, this is the 15 CPU, not like the CPU in my "97 Cali 1100.  I don't have the equipment to do any CPU diagnosis nor re-mapping (IF that is the problem)....just about run out of possibilities to fix this with the resources I have at hand.  Yes, I know where the red CPU led light is located.....will see if "ignition on" will light up any errors therein.  Thanks again

[PeteS]

No one has mentioned the air bleed screws yet. My EV went down the road about ten years ago so I forgot how they were supposed to be set but know they will affect low speed running.

Pete

[Kiwi_Roy]

As I understand the CPU light only works while the ignition is on, I suggest you pick one of the faults listed then unplug the associated sensor to test it, I'm pretty sure the motor has to be spinning.

There must be someone near you with Guzzidiag who could test it for you, it can be tricky getting it to work cold turkey.

Your 5K measurement sounds like just the caps, I meant measure from cap to chassis which picks up the cap, lead & coil in other words makes sure everything is connected

[Kiwi_Roy]

No one has mentioned the air bleed screws yet. My EV went down the road about ten years ago so I forgot how they were supposed to be set but know they will affect low speed running.

Pete

Good point, have you done a throttle balance dead easy with 15 ft of tubing a bit of oil and a stick,
It could be out so far it's running on one cylinder with the other cutting in.

I would still try the lamp on the ECU relay, if it's losing power for a split second, an easy thing to eliminate.

[Chuck in Indiana]

I don't think anyone has mentioned the junk relays the bikes were delivered with. I would replace them, or at least change them around so the injection gets a different one. DeOxit in the relay bases, too..