With out a doubt that's running hotter, you could even have an injector problem or something like a timing issue...

 

 

Crazy thought but you mentioned this only happens when cruising. Is it possible its an airflow issue for the rear cylinder? And I dont mean the normally less flow because its a V twin, but something severe caused by an accessory you have on the bike?

 

Injector swap will be part of the diagnostics process as will timing adjustments.

Interesting that you ask. The builder had a sumping issue with the bike and installed a new oil pump which he said solved the problem. Presumably, there was an issue with the scavenge side of the pump. The bike runs about perfectly so I don't suspect sumping but I don't know much about the topic. How would I check for that?

Apologies if the multiple threads on this build have made things confusing. I've tried to keep each new topic separate from related but distinctly different ones. I figured this would draw the attention of people with expertise in those topics, and it would make the thread more usable (i.e. effectively searchable) for those with the same problem down the line.

That's worth considering, but there are no such accessories on it, and the problem is no better even in cool, moist night-time air.

 

Blue rear pipe only means that the rear cylinder runs hotter than the front; well known. Compare with the rear pipe on a well tuned, cool running 98" motor making 115/115 numbers.

Trying to attach a timing map for Z and a photo of the pipes on my softail to show that they look similar to his; no worries. The images upload fine but I cannot see the "Insert" button at the lower right hand side of the page; don't know why, never had a problem posting images in the past so I am stumped.:icon_shru:

 

 

I had some upload trouble today myself, though ir resolved fairly quickly.

Your word about the color of your pipes is good enough for me, but I sure would like to see that map!

 

Z saw this on Fuel Moto's Facebook and thought of you, lots of good info there

https://www.facebook.com/FuelMoto/?f...-a8716Z4NfgqxQ

 

Trying again but still can't see the "Insert" button at the lower right hand corner. I did manage to "upload" the map but when I uploaded the pipe pic, it wiped out the map. So, map first and pipes second. Well, now I am back to not being able to attach/insert an attachment. Happy to send you the map via email if you want to PM your email address. It is a map for an all bore 107" motor that makes 124TQ/110HP on 87 octane fuel. I do run 93 in south Texas in July through mid September though just to stay on the safe side when ambient temps are 100*+.

I don't know why I can't insert images; have tried on home and office computers, different browsers and still can't figure out why.

 

The PowerCommander literature makes it seem as though the PCIII won't do timing without a separate timing module. There was so much back and forth on this in another thread that I called and asked: it does support timing adjustments, and no separate module is required. Totally understandable that you'd come to the conclusion you did. I confirmed by looking more closely at the app, and saw 2 tables for timing.