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Why can't You Just Twiddle the Air Bleed's Until Idle Smooths?

Bonaventure

Cruisin' Guzzisti
Joined
Jul 30, 2017
Messages
181
Location
USA
I was wondering. If your higher rpm operations are acceptably smooth, but idle quality has become chunky how come you can't just adjust the air bleed screws until idle smooths out and not do anything else? Given that beforehand you run each screw in counting off how much so you can make note of the reference position they were in before you started.
 
One bypass screw should remain closed. Please read procedures on doing a sync. Does it really matter if idle is "chunky"? You shouldn't be idling much anyway. If Idle is "chunky" after doing a sync, the air passages in the stepper may need cleaning. There are posts here on how to do that.
 
One bypass screw should remain closed. Please read procedures on doing a sync. Does it really matter if idle is "chunky"? You shouldn't be idling much anyway. If Idle is "chunky" after doing a sync, the air passages in the stepper may need cleaning. There are posts here on how to do that.

Bike is new, prepping to do the 1st service myself, they should be clean. However, there is one point which I don't think matters but that i noticed and not sure actually how I *missed* it during my initial eyeballing of the bike right after getting it home August 29th. The vacuum line from the Stepper Motor for bypass air to the right hand (starboard) TB was not on very good there was what looked like nearly 1/2" of the brass nipple showing. It won't push to fully flush like the left side's best I could get it is to about 1/8" of nipple exposed which should be fine since the hump on the nipple is fully and securely enveloped now. I'd thought that to be the cause of the idle miss, but pushing it on properly made no difference as of a test ride afterward yesterday after work.
 
What is the idle miss you are talking about. Is it it blips every so often. If so, somewhat normal. Usually it is the lambda probes or stepper adjusting for imbalance. Gets better the closer you are to perfectly balanced. Does not indicate an issue. Never misses at throttle.

Don't overthink this bike. Most of the thinking has already been done on the majority of idiosyncrasies it has. It is just the way it is. It will drive you nuts trying to get it to run like a Honda. If you want that, wrong bike...;)
 
What is the idle miss you are talking about. Is it it blips every so often. If so, somewhat normal. Usually it is the lambda probes or stepper adjusting for imbalance. Gets better the closer you are to perfectly balanced. Does not indicate an issue. Never misses at throttle.

Don't overthink this bike. Most of the thinking has already been done on the majority of idiosyncrasies it has. It is just the way it is. It will drive you nuts trying to get it to run like a Honda. If you want that, wrong bike...;)


No, it's more of a constant chuggle ... a miss every other or every third fire. Also random misses between idle and about 3000rpm. Started doing in the last 100 or so miles, prior to that it was as you described. I pulled the spark plug covers and made sure both plug caps were okay-- they were. But it seems like an ignition misfire?
 
Start with a proper sync and TPS reset just to eliminate that potential. Does not sound sync related but hard to say. What is the TPS reading?

Even though the plug caps look good they can have internal splits in them. Are there any white spots on the boots That is a sign of arcing.

Confirm those things and then we can see where to go. That being said, assuming bike is still under warrenty so may want to speak to the dealer first (of course, not sure how good that will be??).
 
Start with a proper sync and TPS reset just to eliminate that potential. Does not sound sync related but hard to say. What is the TPS reading?

Even though the plug caps look good they can have internal splits in them. Are there any white spots on the boots That is a sign of arcing.

Confirm those things and then we can see where to go. That being said, assuming bike is still under warrenty so may want to speak to the dealer first (of course, not sure how good that will be??).

Choice of dealers is Sloan's in Murfreesboro who are sharp and very expert but almost 4 hours ride, and motorsports dealer 90 minutes away who seems to carry a couple Guzzi's as a distraction and mostly handles dirt bikes, ATV's and side-by-sides. Not inclined to use the 90 minuter, I could see them moving the sacred screw. Maybe not but who knows.

When I bought the bike form Eurocycles of Las Vegas I did so with the knowledge that I would be my own warranty except for major repairs.

No white marks on the spark plug caps they look brand new and perfect. Thumbing them gently revealed they're firmly attached.

There is a very off-chance that it being in last 100 miles it could be fuel related. I'm 140 miles on the trip odo since fill-up. It has begun exhibiting these things on that tank of fuel. It was 91 premium but convenience store gas. Granted, a reputable franchise type store, but who knows. Prior to that all fuel has been Marathon 93. Both numbers are R+M/2, USA octane spec.
 
Choice of dealers is Sloan's in Murfreesboro who are sharp and very expert but almost 4 hours ride, and motorsports dealer 90 minutes away who seems to carry a couple Guzzi's as a distraction and mostly handles dirt bikes, ATV's and side-by-sides. Not inclined to use the 90 minuter, I could see them moving the sacred screw. Maybe not but who knows.

When I bought the bike form Eurocycles of Las Vegas I did so with the knowledge that I would be my own warranty except for major repairs.

No white marks on the spark plug caps they look brand new and perfect. Thumbing them gently revealed they're firmly attached.

There is a very off-chance that it being in last 100 miles it could be fuel related. I'm 140 miles on the trip odo since fill-up. It has begun exhibiting these things on that tank of fuel. It was 91 premium but convenience store gas. Granted, a reputable franchise type store, but who knows. Prior to that all fuel has been Marathon 93. Both numbers are R+M/2, USA octane spec.

Could very well be. Fuel quality is a gamble sometimes, no matter where you are. Should not be missing as much as you are experiencing.

If it does turn out to be fuel, may want to check the drain hole under the cap. Know spot to plug and then if it rains, or you wash it, water can get in the fuel. A shot of compressed air every so often keeps it clear. There is a brass hose barb on the drain line with an opening the size of a needle head. Best to remove it and run a solid line from the tank to the bottom of the bike, or put a larger nipple in.

Other thing to check is make sure all the grounds are tight. This includes the battery and the mains to the chassis behind the starter. Just follow the wire from the battery and you will see it. i doubt it is corroded up this early in the game so just make sure they are tight. They can also cause the cutting out.
 
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No, it's more of a constant chuggle ... a miss every other or every third fire. Also random misses between idle and about 3000rpm. Started doing in the last 100 or so miles, prior to that it was as you described. I pulled the spark plug covers and made sure both plug caps were okay-- they were. But it seems like an ignition misfire?

I've had a similar problem on my Norge 8V, I disconnected the vapor recovery lines, replaced the one way valve, and blew compressed air through them, I did get a lot of water come out of the line between the canister and the tank overflow vent tube tee. and I noted the the line that is routed downward, was facing forward at the bottom acting like a "scoop" for water (I'm not shy about riding in the rain). This apparently filled the charcoal canister, and I have a new part on order. A side effect of this problem is also that the fuel tank gets sucked in, due to the vacuum not being released in the canister vent port. I replaced plugs, injectors and coils chasing this problem, and even though I am a certified Moto Guzzi technician, and kind of embarrassed to have spent so much money trying to fix this Norge, I am happy to have resolved it.
 
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