Cool Weather vs. Hot

[JeffOlson]

In cold or cool weather (30s, 40s, 50, and even 60s), my Norge runs great. It is smooth. It purrs. It shifts well. It tolerates low revs. I love it!

In hot weather (80s, 90s, 100s), however, it does not run nearly as well. It groans, vibrates, bucks, and lurches. It will not tolerate low revs. It is like it is a different bike. If I did not know how well it runs in cold or cool weather, I might not put up with it. I might ride my Vespa instead.

What gives, and what can be done (other than riding my Vespa)?

[Gliderjohn]

Hmmm! Not noticed any of that on mine. Don't know.
GliderJohn

[Groover]

Is the Norge FI or Carb intake? If carb, then you can richen the low end needle valves on the carbs maybe 1/2 to 3/4 of a turn on each (richen = unscrew them counterclockwise on Dellorto carbs). If Fuel Injected, then not sure. Maybe the map (If applicable) needs to be tuned to richen the low end a bit,

[JeffOlson]

^ FI.

It looks like I need to borrow a PC from my brother and upload Mark's latest Norge map. (I have Macs, but the GuzziDiag writer program cannot "see" any maps on my Macs, so I am not able to use it to upload a new map.)

[Bobolink]

Do you still have the evaporative canister? After removing mine, the bike seemed to smooth out a bit. 
You may want to check TB sync and valves.
I'm not sure if there is a ambient temp sensor that alters fueling, but I had a hot weather cold start issue with my Norge; my issue, however, seems to have corrected itself after two years.

[Bobolink]

Marks map, as good as it is, may not help if something is out of tune.

[Groover]

I've messed with maps on a bike I used to have and I tried trading maps with other people around the country at different sea levels; What worked well on one bike didn't work well on another, same variables otherwise. That was a power commander III unit that would override the factory ECU. If it's that type where you can adjust fuel levels at different throttle levels, then I'd go in (back-up your current map before messing with that if that is an available feature) I'd try that. For now, I'd just focus on your low end though. I think that's the area more sensitive to temperatures and atmospheric levels. The upper end usually has enough "slack" to work anywhere (within reason).

But again, I'm just guessing here. I don't have an EFI Guzzi, so take what I'm saying with a grain of salt. Hopefully someone whom is doing this more frequently will jump in a help you out.