I have posted recently about check engine light comig on when bike is started cold but sporadically. A few days ago when bike idling in driveway, it started "gasping" for lack of better description--spittering and sputtering like intake leak. Took bike in for 20k service and had them check codes, and it is showing low O2 sensor front and rear and mechanic says it = lean running bike. Started bike cold at dealership and had the sputtering and then it stopped when bike warmed up, and they could not replicate it or find a leak with exhaust or intake when spraying fluid by it. He thought I should run injector cleaner in tank of gas as first offense and secondly replace intake gaskets if not addressed.

Any ideas gang?

Have 07 ultra with stock engine. 2:1 D&D fatcats wtih big sucker ac. Bike has run fine with thundermax for 19,000 miles with existing setup. I did change the map recently to run a bit richer and retarded timing 2 degrees at a few spots to address roll on ping.

 

Did this happen right after you did some tmax editing or at some later date? You could link up and do a monitor of afrs front and rear to confirm lean. Not sure how the dealer was able to reach a conclusion on the O2 sensors since the diagnostic is done from the module via link up and to my knowledge will not show up on the normal speedo check. Could be wrong on that, but even if you unplug the data port no error code will show up on the speedo regarding O2s. Only linking up to tmax tells what's going on. The only other thing that comes to mind would be low fuel pressure, or injector problems either mechanical or electrical effecting one or both. Maybe a faulty head temp sensor as well, but linking up with the correct gauges displayed will give enough data as to where to look.
Ron

 

thanks for you input Ron. The check engine light came on a few times before I changed the timing and afr, but the gasping for air symptoms are new. It also seems to be backfiring more even with decel activated to 1 on map. tonight after I posted and got home, I loaded the old map that i ran for 18k and will try it for a few days to see if the problem goes away. If it does, my mods were the culprit. If still present, will need to look further. The bike otherwise runs good. i was just trying to take out small amount of pinging in first gear when leaving stop light and roll on pinging if passing and really cranking the throttle.

 

Loaded map I had run for 19k miles, and bike is still gasping for air on cold starts, seemingly right behind the air cleaner. Any ideas?

 

You can check for an intake leak using carb cleaner. With the engine idling, spray some at the point where the intake manifold meets the head, one at a time. Careful not to spray it into the air cleaner. If you notice a change in how it runs every time you do that you probably have a leak.
I think HD has a propane tool they use for checking that, but if you can do it without buying a special tool I'm for it.