I have a 2005 dyna fxdx (injected) with 4500 miles. When I bought the bike (500 miles ago) I could tell the owner didn't maintain it well (appeared to have been sitting for a long time and was low on engine oil). However, the bike has the hd extended warranty good through next year and I have the documentation from the owner for the "required maintenance". I changed out all the fluids powder coated a bunch of parts and installed a thunder header exhaust. For the last 500miles, I had no issues. On my last ride (just before we left for vacation) I noticed while going up a hill at 3/4 throttle, the check engine light brifefly came on (1-2 seconds). It came on 2 more times (both for 1-2 seconds) while riding home during pretty hard (close to wide open throttle) acceleration. Each time it came on, I did not notice any difference in the way the bike was running.

At home, I diagnosed the code and got the "front cylinder no combustion". I was planning on waiting till the warranty expired before installing an intake and re-map that way I wouldn't void the warranty (I understand the exhaust alone could void it, but pipes can be changed back to stock easily). I also understand that running pipes with stock intake / fuel settings could cause the bike to run lean. Do you think maybe the bike running lean caused this code to trip? Is this something to stress about if it only turns on briefly then turns off? Any other suggestions on other things it could be? I've just been kinda stressing about this while on vacation and wanted to know what you guys think. Thanks!

 

My experience with the check engine light and the trouble codes is they are trustworthy. I had a cam position sensor fault on my '01 injected ultra classic, so I ordered a replacement. When my mechanic swapped it he showed me the old one, which had frayed wires. So, it was accurate. The bike ran perfectly the whole time.

I got the service manuals, including the electrical system manual for my '09 softail, but I'm sure I'll never need it. ;-)

 

Could be as easy as a loose sparkplug or sparkplug wire. Make sure you have stock wires and new stock plugs and go from there