What can I do to this to get a noticeable increase in power?
That's a 6.0cc Fred Head on top and really need the cooling that gives. Maybe his new 5.3cc? Would that really make much of a difference?
The thing that works this the hardest is towing a 80-100 lb trailer up logging roads and such. That's what I need the power for.
SBP Jackshaft shift kit has all the lowest gearing. 30 tooth front chainring goes to a 11-34 rear cassette, so a pretty good range there (this is an old steel frame with 6 sp freewheel, so I spread the rear from 125mm to 135mm [Subaru screw jack worked great] and put on a modern sized wheel/axle with 7 sp 11-34 cassette--working great so far).
I've done some port matching. Not sure if there's a better exhaust that would make a huge difference without being some 4' long behemoth. Better intake/carb?
Also, something I seem to notice regularly is when I twist the throttle to full throttle, past a certain point, the engine bogs down. It's like it's getting too much fuel or too much air or something. Same thing with two different 'stock' carbs, so... Wonder if i could solve that if part of my power problem would be solved.
Any other thoughts?