HarleyTechTalk

Maybe your chasing the wrong gremlin.  Because the issue has worsened and increased it's frequency with the number of start cycles it would make me consider the compensator.  You call it a backfire but that's a subjective description.  Is it sending fire and smoke into the breather?  As the pre 2014 twincam compensator aged and got weak, the first crank (or more) would kick off like a little explosion and spin the engine back (often resulting in a grind / bang / stall like reaction and a subsequent intake or exhaust loud firing back and puff of smoke).

Have you checked the compensator health? You still haven't given a full description of the model, year etc. of the bike.  IIRC the earlier M8 compensator was problematic.

I also recall some posters saying something similar to your basic description was happening and if they tapped the start button and clicked the bendix in once then on the second tap held the button in it would start normally.

Assuming you are 100% certain you have a recurrent intake leak:
Have the heads been off ever? Or milled? Are the surfaces where the seals hit still flat and true?
What air cleaner you running? The fitting of the backing plate can "pull" an intake and the manifold away enough to blow the seal(s).

I was just reading the latest engine labs about using the fuel. They also mention what it does to your oil. I don't know how to upload pictures from my phone on this site. But worth a read.
Andy 

So, here it is a year after this whole thing started. Still having the same problem. I have also changed the MAP sensor. no change. Can't find any bad wires (yet). If it didn't run perfect, maybe I could find something to fix. Any suggestions ?

One guy I know who runs E85 has right around 15.0:1 compression.

Quote from: Ohio HD on Yesterday at 01:05:56 PMAs long as there's not a ridge that you can feel it looks to be just normal wear. Did you keep the lifters segregated so that you can look at each roller as compared to each lobe

well some good news at last. yes but i'm hesitant to reuse those lifters. 

It appears that 5/5 % gain is the number talked about in un-boosted apps .
I could see a huge downside would be keeping moisture out of the fuel.
Do you live in a humid climate ?
You would (should) likely need to flush the system with regular gas between rides .

16 hours !!!!!

Where the heck was that book when I was working on flat-rate

I think I could change a 6 speed cassette blindfolded in 6 hours LOL 🤣🤣

~John

Don't know but I changed mine out of a carburetor model electra glide by going at it from the left side.  I remember it being tight but I was able to do it.  I believe the little screw was the biggest challenge not to drop it into oblivion.

As long as there's not a ridge that you can feel it looks to be just normal wear. Did you keep the lifters segregated so that you can look at each roller as compared to each lobe?