Steve sorry I hadn't shared the cylinder head mount tip with you earlier. Hope it didn't slow you down.
Welding the base plate to the cylinder tube from the backside is actually the cleanest presentation even if you had sufficient room to work from the top.
Having a removable cylinder head with a center top spark plug location can also aid with motor mounting in tight frame space. mount plug in head prior to mounting saves 1/2" top clearance.
Great progress being made Steve let me know if situations arise that cause??
I'll mention motor cooling in a completely closed space. If you recall I left my motor case partially open on the bottom & the motor case vents on the side cases exposed to air circulation as well, then added side covers that are also open on the bottom.
There is no way you folks up North have the desert heat we have in the Indian Territory, but air cooled motors still get too hot to be totally enclosed during continuous running. Controller needs to also be in the air stream for case cooling and each battery requires at least a little space around it when enclosed in a separate housing. We hit stretches of weather occasionally of 10 to 30 days over 100 degree F., though we've not experienced these for several years now, so heat is a big deal in my thinking when dealing with any air cooled motor I.C. or electric.
Rick C.