My V11 sometimes idles uneven when warm and even pops and almost stall

[Emil Jensen]

My rather newly bought Moto Guzzi V11 Le Mans from 2002 (13.939 miles) has a small problem. Sometimes when it is warm it idles uneven and even pops and almost stalls. It seems like one of the cylinders don’t take in gas at one of the blows and then it sets out and pops in the exhaust, almost stalling. It only happens when it is warm – when it’s cold it runs like a... well like a cold motor!

 

To fix this I first suspected the valves which I then adjusted (they were way off – check below) and at the same time I had a look at the air filter which looked fine. The problem was improved, but it was still there. This weekend I then calibrated the TPS and balanced the throttle bodies. So far with no result. Also I did a compression test, but I might not have done it properly. I just unplugged the sparkplugs and skrew in the compression tester in (I just read, that you should have the throttle wide open and I didn’t).

 

Compression Test: Right cylinder: 120 PSI - Left cylinder: 114 PSI (totally warm engine)

 

The valves before adjustments:

Intake ®: 0.203 mm

Exhaust ®: 0.203 mm

Intake (L): 0.178 mm

Exhaust (L): 0.254 mm

 

Hope someone out there can figure out, what is wrong with my Guzzi – thanks.

 

PS: I have attached two pictures of the sparkplugs – perhaps that can give a clue?

[docc]

Unplug your coil wires form the coils and be certain they are clean and free of corrosion.

 

Setting the TPS and balancing the throttle bodies can be accomplished by several different methods. You might want to try an alternate method and be aware the indicated idle on the tachometer may be 500-700 rpm high.

[Kiwi_Roy]

Yes check the compression with a handful of throttle.

 

The difference in compression might be just a throttle imbalance.

[Trevini]

It might be worth checking the inlet rubbers. They seem to be quite prone to cracking and splitting, causing an air leak. Cheap and easy to fix. The other thing it could be, but I don't know how likely it is, is the temp sensor for the FI. That might be fooling the ecu into thinking it's a different temp to reality.

 

Trev

[fotoguzzi]

sounds a little like mine before I changed out the Cross Over for a Mistral one.

[jcbooghs]

from raceco UK:

 

Tappet clearances for the Guzzi big twins should be set to 0.20mm for the inlet and 0.25mm for the exhaust. This also applies to the "modern" Guzzis such as the Sport 1100, Cali 1100i and V11. The factory settings for these bikes are 0.10mm and 0.15mm respectively, but this is to try and reduce engine noise to meet US emissions regulations. With tappets set this tight the engines have trouble ticking over and running cleanly at low revs.

[Kiwi_Roy]

My bike has the Italian sneeze also, it every now and then seems to fire early sort of kicks back like it wants to run the other way when it is idling slow, never does over about 1200 revs indicates. It does this with the stock or MyECU.

It seemed to ease it a lot when I opened up the tappet clearance but not gone completely. Perhaps it's just idling too slow, I keep meaning to check the tacho against a frequency meter.

You can check the revs by measuring the alternator frequency x 60 / 7

[rossoandy]

from raceco UK:

 

Tappet clearances for the Guzzi big twins should be set to 0.20mm for the inlet and 0.25mm for the exhaust. This also applies to the "modern" Guzzis such as the Sport 1100, Cali 1100i and V11. The factory settings for these bikes are 0.10mm and 0.15mm respectively, but this is to try and reduce engine noise to meet US emissions regulations. With tappets set this tight the engines have trouble ticking over and running cleanly at low revs.

 

 

Same issue here...my gut feeling is running lean...just about to check clearances and plugs,inspect inlet rubbers too. I wondering if an engine sensor is messing around, ie temperature or crank sensor......a process of elimination...

[mznyc]

If your tune up adjustments are correct and good,I would inspect for an air leak.All connections at headers,X-over fore and aft and the TB boots.I would say nearly 50% of the bikes that have these symptoms show the boots to be bad.

Plugs look good,in the normal range.

[rossoandy]

from raceco UK:

 

Tappet clearances for the Guzzi big twins should be set to 0.20mm for the inlet and 0.25mm for the exhaust. This also applies to the "modern" Guzzis such as the Sport 1100, Cali 1100i and V11. The factory settings for these bikes are 0.10mm and 0.15mm respectively, but this is to try and reduce engine noise to meet US emissions regulations. With tappets set this tight the engines have trouble ticking over and running cleanly at low revs.

 

 

Same issue here...my gut feeling is running lean...just about to check clearances and plugs,inspect inlet rubbers too. I wondering if an engine sensor is messing around, ie temperature or crank sensor......a process of elimination...

Cecked all above yesterday,compressions fine at around 130psi,tappets ok too. Obserbing the engine running at a fast idle of 2000rpm I could see the coughing was on the left cylinder only, now thinking a dodgy injector as the new plugs I fitted are running lean on this cyl too...