I would have to think the bike is a '44 . No fork rebound springs . 2.5 gallon tank w/ right side fill .
I can't see where the kick stand is ...
Seems everything points to '44 .
Pete .
I think you guys are wrong. I'd say 45-47 model H. If it was earlier, it wouldn't have the brake pedal on the right toe, it would be heel activated. To me, this is the biggest giveaway. Plus, look at the air filter, that doesn't look like an oil bath to me. I also notice that the transmission mounts are flat steel, whereas earlier models were tube.
With all these cues, one would have to assume that engine is correct for that frame.
If I had to pinpoint the year, I would say 1945. The kick starter came around 1946, I believe, and was a bolt-on affair.
Thanks my 2 cents!