As IAN,s just the same only 240 beans but never had an issue..use cheap as chips supermarket mineral oil...
but do have to service every 3rd run up the strip....”plates dryed out”...
Carbs would be a good place to start ...but I would ride it a few miles 1st before diving in and have a look at the filter
And check its not one of them "custom" oil cooler protectors on it as I,ve seen some that cut down the air flow
Dept on skills there not hard to do in steel
I used the original EFE front plates to position the engine and made the rest to suit from various engine plates I had kicking about
The position of the engine is another debate as some mount it forward "reduces exhaust issues"
some put it in the middle some to the rear
Ooops forgot the left hand rear top mount is welded to the frame on fatty so you need to cut it off and make a new one..
I would check you have power from the solenoid to the starter
And then take the left hand cover off and investigate further
could be starter clutch or intermediate gear issue