I had the same engine on the Dune cycle in the '70sIf you would have used bolts for the exhaust you get more area for exhaust flowMine had a header made out of bicycle handlebar and it ran really good
Valve Springs, If you don't have a spring compressor I use an open end spanner aided with a flat head screw driver, place spring and seat on top of the spanner insert into cavity drop valve in maneuver seat into place on valve use screwdriver to hold in place remove the spanner and your done.
instead of cutting that cam pully of id have made use of it and use it to power a generator for lights and a charging system. i have a 3hp thats on a 60s model tote gote. most reliable thing ive got and its all original parts. ive just refurbished them with homemade gaskets and permatex ultra copper. the exhaust is conduit and a cheap muffler from tractor supply. runs good
It's the valve springs are weakened from over the years of usage is what's causing that issue with the low compression reading's.,or your compression gauge is bad now one of the two. I know that those valve springs do get weak over time from wear and tear. Right along with heat friction and cooling back down repeatedly to over time does it them.,or the engine being ran on low oil causes those same issues as we'll. It's called heat sink friction expansion and contraction. Witch basically means it stretches the valve springs out from the heat inside of the engine from swelling up and shrinking back down when cooled down.
I know of Away that you might be able to still get that bolt out of the engine block by using A propane torch lightly heating up around the threaded surface area of the bolt hole that's after drilling it to fit A reverse drill bit witch is similar to A easy out bit to. Tap it in lightly with A small ball pin hammer to set the easy out in good to use A wrench to turn it slowly while it's still warm spray the threads with some PB-blaster oil first. Then proceed to slowly turn the bolt gently wrench straight inline with the bit to loosen it up. Good luck to you. Heat it up enough until it barely starts to kinda let off smoke fumes then try the rest of it all out.
@MechannibalGarage65 I would of welded a nut onto it I'm getting ready to do that with a kawasaki engine side shaft engine I have no choice can't thread in exhaust I paid 20 for it runs great just have to get them out also how would you hook up a throttle cable to this carb for minibike or go kart?
Well this isint exactly a mod you just threw a pipe and carb on what you can do for under 100 bucks is open up your intake and exhaust and shave the head for extra bang for your buck they also do sell racing parts for flathead brigs
