I'm in the middle of diagnosing this issue, however I thought I'd post it up and see if anyone can shed some wisdom.

Basically, when the bike is warm (or it's hot outside and bike has been sitting in the sun) the engine fails to stay alive after startup. I turn it on, let the sensors read and the lights to go away and hit the start button and it fires. But almost immediately the idle becomes choppy, the rpms rapidly decline and the engine shuts off. To bypass this and keep the engine going, I hit the start button again and give it some throttle for 15 seconds or so and after i let go the idle is rough at first but then balances out and goes to normal.

Key things to note, when this happens, upon the initial combustion of the engine coming to life...i notice a flash of dark smoke coming from the exhaust and a hint of the sweet aroma of fuel (though that may just be me). Also, this doesn't happen all the time. Oddly enough when i try to show other people it fires up, rough idles for 3 seconds or so and then goes to normal.

So I was thinking that it's either one of the sensors on the induction module or a problem with the fuel components in the tank. I bought some maf cleaner today and when i get a chance I'll clean off the IAC. If that doesn't work I was thinking maybe TPS? and after that i was gonna go digging in the tank.

What do you guys (and I mean the ones who know what they're talking about) think?

 

Under warranty?, take it in and let HD fix it.

 

I'll take it in as a last resort. It would bring me great joy if i was to solve this problem in my garage.

 

Ouch dude, you've already whittled me out of the gene pool!

But that won't stop me

For the heck of it, first thing I would do is check your codes to see what the bike itself says about it's self.

 

If you can't plug it into a diagnostic tester you'll only be guessing as well as any one else that tries to help. there are too many variables that can cause a rich condition at start up.

 

So first for the black smoke and fuel smell. That might be because the engine stalled before the fuel in the combustion chamber ignited causing excess fuel to be ignited the next time you fire the bike up. As for the heat issue, it reminds me of problems you see on electronic devices when a circuit board gets too hot. As heat expands the board the connections are severed causing a failure. As it cools down the connections are reestablished and the device will work again until the board heats up enough to break the connection again. The first thing that comes to mind on a motorcycle is the ECU/Coil. I have heard of this type of heat expansion causing issues with ECU/Coils before. That's the device that delivers spark to the combustion chamber. Without consistent spark the engine can stall or run choppy. Good luck!

 

try this leave it outside too get very hot,,, remove your gas cap,(HOLD IN YOUR HAND) then start your bike any see if its any better,,,,,, if its great then a faulty cap causing VAPOUR LOCK

 

Check for codes. if no help take to HD and let them sort it out.
It's under warranty use it.
Small things I sort out but if the codes don't help I take it to hd for a fix if under warranty.

 

haha, yeah I realize now how that may have sounded from the readers point of view. but you're right, i did check for codes and two came up. it was also the first time i've ever checked for codes and the two codes were P0132 & P0152; something to do with O2 sensors i believe. erased them, ran the bike, checked again and they didn't return.
EDIT: sorry, i had written these down early this morning. there was a 3rd code that read B1210 in the speedo section. i looked it up and that one is not listed. has anyone ever seen that one before?


that makes sense, i'll look into electrical. i think i'll also check battery voltage, because it only happens at start up. after the idle goes to normal it runs perfectly.


you mean start it with no gas cap in? alright i'll give it a go. could be it, since i recently put in the HD flush mount cap/gauge. could you explain vapor lock to me, though? never heard of this

 

after about owning 24 bikes I had it happen too me Suzuki 1200 bandit
I would leave the bike outside in the work car park , hot weather 44c temp you do Fahrenheit conversion, I would start bike and ride off ,thing would stall then run like **** undo fuel cap ran great,,,
OKAY YOU replaced the CAP that could be the issue,, as a cap has a small vent hole too let air in the tank , hence my thoughts VAPOUR lock,,,ive been wrong before but try it my friend, if it works please send a carton off Budweiser too Australia :icon_banan a: