My 2003 Ultra runs perfect for about 20 minutes and then backfires (sometimes more then other times backfiring) and it shuts off, cranks but won't restart until it cools off for 30 minutes to a hour, then runs perfect again, for a little less time then the first cold start. So I feel like something is going away when it gets warm?. When cranking it during these incidents, it acts like it is either real hot or like timing is off as it will kick back. No kick back when this misfire is not happening. Before it cuts out I notice the idle being off (I have to give it a touch of throttle to keep it running at idle after 15 minutes or so). It seems hot, hotter then normal. I did a little research and decided to change the temp sensor thinking it was a cheap easy test and thinking the sensor might be faulty giving a false reading and maybe the ECM was not giving enough fuel when warm because of a false temp reading, but that sensor swap did not make any difference.

I have had the bike and put 60K miles since 2011 (over 100K now), I know the bike pretty well. This is problem is new.

I am afraid to send it to the dealer, I would like to avoid the million dollar route. I do full nut and bolt frame off car builds, so I can fix it if I have a idea of what I am looking for.

You guys never cease to amaze me, curious your thoughts?

 

Hoses in fuel tank and the regulator, replace them both.

I had the same issue a few years back

Get a new gasket and the little washers/seals that go on al the screws.

 

Crank position sensor

 

Did you check for codes? There are quite a few things possible. If there are no codes I would start with crank position sensor since I have seen them be an issue and not set a code. It could be the EFI control module. Could be coil related from the heat causing an open condition.

 

Could be a few different things , but I would start , like mentioned , checking you regulator , charging system . When a faulty regulator gets hot , it will act up . Follow these test and you'll soon know .

It wouldn't hurt to have the battery load tested as well , rule out the possibility of a bad cell .

https://www.hdforums.com/forum/elect...sting-1-a.html

https://www.hdforums.com/forum/elect...sting-2-a.html

A coil can also be a problem when hot , a spark tester could reviel a no spark condition , or testing the coil .

Yes , crank sensor could be an issue , check the connector , clean it , then pull the sensor , wipe it off , check it for damage , run the bike and see if it improves .

While your at it , clean your iac , use tb cleaner , and cycle the ignition , don't start it . Put a rag inside the tb to catch all the debris . Then clean the butterfly and seat .

Check for error codes before doing anything , or buying new parts , the codes will / should lead you in the right direction .

 

All of the above and also check your battery connections, make sure they're tight. Them being loose do funny things.

 

If you want to rule out fuel hoses and the fuel pressure regulator, when it dies spray some starting fluid (SPARINGLY !!!) at the filter (for diagnostic purposes remove the football cover and tape off the hole in the air cleaner) and see if it fires off, If it fires on starting fluid then you can rule out spark, crank position, etc and look at fuel as the problem.

 

Check the gas cap vent

 

^^^ This! Start simple. Just loosen your gas cap. Sure sounds like a venting to me.

 

As for the battery, knowing I might very well be starting it a lot on a "test drive" - "test breakdown", I put a brand new 400 Amp battery in it. So I know the connections are good. And the battery voltage was 13.6 steady. Voltage regulator is not that old, but in my car business, new parts, especially aftermarket parts fail all the time. but I should see that through the gauge shouldn't I? I will watch the gauge close.

As for codes, I understand with stock gauges you can get codes? But I have Dakota Digital Gauges. Is there a place to hook up a code reader?

Loosening the fuel cap sounds easy enough. And doing the fuel tank hoses seems easy enough. I have been focusing on a electric / spark / ecm issue not thinking about fuel delivery.

It will be cool this evening, I will loosen the fuel cap and take it for a ride. Need cool weather if I might be sitting on the side of the road for a hour.

Thanks all so far, i will report after my test ride.