Besides what Devin said, I would check out (or replace), the lighting coil down on the stator . . . it could be a loose or broken wire that breaks continuity when it warms up . . . thus the intermittent loss.

I can send you some pictures of the tank.

Thank you! That helps a lot. My bike is missing that bracket… so I will try to find or make one!

I got it off using a Slide Hammer. I contacted a friend who worked at a dealership in the city I have resided in for nearly 70 years. His dad owned the dealership and he wrenched in the back for a for decades. He said that they used a slide hammer. I fashioned an adapter to fit my live axle puller and it came off in a single light pull. It surprised me a bit because I was thinking it was welded with age.

Page 31 .... Hummmmm ... could depend on what version of service manual you are veiwing.

I will say, that if the service manual is followed from start to finish, that would eliminate "most" of any problems that could arise.

There is a shifter mechinism adjustment that must be done/adjusted correctly.

I must say, it's Kind of hard to help with something like this without being there in person. Pictures "might" help

Hello skoppang

Could be any number of things. I recently fixed a 68 DT1 engine with the exact same problem, and it turned out to be ... that whoever was in the engine before me had left out a particular shim on the secondary transmission shaft, that prevented it from going into fifth because the shift fork couldn't complete the shift (throw/movement) without it.

Another suspect area to check would be the shift cam detent mechanism.

Note: Often times the transmission shaft must be rotated a bit to complete a shift, because the cogs on the gears aren't nessesarily lined up.