Stored in a warm place with stable temperature the whole winter.
Tank filled two last times last Fall with well preserving small engine gasoline which was used successfully also during earlier storage period of a couple of months.
Air filter cleaned last Summer.
Battery is 2 year "similar as the original HD battery" from an HD shop. Just load tested to be ok. 12.9 V two hours after charging and after a couple of starting trials still 12.6 V. Still also jumpstarted with a car but that did not help either. Changed new spark plugs although the earlier ones were used only for one summer. Gives a visible spark.
Even cleaned the battery terminals and measured the contacts. Connections should be ok. But always the same: after turning ignition on, a small normal sound of a few seconds after which I press start button and the starter rotates well, but nothing else except some smell of gasoline after trying to start the engine a couple of times. Has the alarm system but that seems to disarm normally. And yes, the killer switch is in the run position.
Any hints?

 

You might try draining the fuel out and refill with fresh fuel. Does it sound like you have good compression? Sticky valves?

 

Valves ok. Compression should be OK as it takes air in and blows out from pipes. The gasoline is of special quality and is good and recommended for storage for very long periods so I have not yet changed fuel. The battery was removed for winter. There is only little smell of gasoline but not much even after long attempts for starting. Could the alarm system and the fob be somehow out of sync? It seems to work ok but is there a chance that it does not disable sparks and starter but disables fuel injection? Fuel fuse seems ok and changed with the lamp fuse but no change.
Does the jump start from a good car battery in a running car with 1000A thick cables provide sufficient current or should I just buy an original HD battery if the copy battery somehow draws too much of the current to itself i.e. low internal resistance. It warmed up but only moderately.
Thanks for the good hint so far. More hints wellcome.

 

I would definitely drain the gas and try new first

 

Have the battery load tested at an auto parts store. You said you removed the battery. Could the back up battery in the alarm have died out?
https://www.hdforums.com/forum/dyna-...r-sitting.html

 

I know some dont believe in it but have you tried starting fluid?

Is this CArb?

EFI=Low fuel pressure can do that too! (pinhole in intank fuel line, clogged fuel filter)

If the injectors are clogged they my give you enough to smell but not enough to start.

Also, not sure if you have the IAC on that model year but I do on my 07.......if that sticks it wont run. There are youtube vids on how to clean.

 

Try pushing up on the fuel line where it attaches to the bottom of the tank while cranking. If you are be careful, pull the air cleaner and squirt a little fuel down the intake. What does the gas smell like.. A hint of stale and it's best to dump. Can you hear the fuel pump run after cranking? It's the same sound you hear when you first turn the ignition on.. It may be worth doing a compression check..

 

Problem solved eventually. Battery load-tested in a professional HD-store. Back-up battery OK (powered the alert when I disconnected the main battery in the armed-stage). Changed 15A fuses and the two relays but no help. Was able to run the engine for some seconds by almost completely blocking the air intake. Same behavior with old gasoline and after changing new gasoline in steps to get all old out. Warmed both cyliders with this manual chole to some extent. Did not dare to use the starting fluid. So, took most of the gas out and added a good dose of the gas line purifier to the tank, disconned the fuel line from the quick-connector below the tank, cleaned the connector ends with pressurized air. Then let the pressurized air onwards via the fuel line, reconnected the the fuel line to the tank. Then started properly with the first trial and run like before the winter storage :-)

Thanks for all hints.