I just couldn't get that flathead to run the way I wanted. Since this isn't a vintage bike, I had no problem going to a predator. This hemi has been sitting new in the box on my shelf for a couple of years. I put a non hemi crank in it to use a clone cast aluminum flywheel. It has a Banzai .265 cam and a real Mikuni. The torque converter has a Juggernaut and a 10t sprocket. It wants to pull the front wheel up when you take off and I hit 46mph quickly on my first test run before I chickened out. My next run I was properly dressed for riding. I drove around a bit to warm her up before I let her rip. I never got any further. My side cover came loose and leaked oil everywhere. I had everything torqued correctly. This happened on the last predator I put together. The dozens of others I have had the cover off and on didn't have this problem. I decided to order a stud kit and not worry about it anymore. I ordered a 12t sprocket and a kickstand. Once that gets here and I weld it on I should be ready to paint and wire it up.
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Loose side cover bolts is a sign of too much crankcase pressure. That stock valve/baffle, in valve cover can't keep up with that higher rpm, and it will hang open too long pulling in air, as the piston goes back to top of cylinder. Its only designed to operate around 4000 rpm.
I've installed a vacuum/ pressure gauge for testing crankcase pressure, using a billet side cover port, and seen a big burst of pressure all of a sudden, really fast, then back down to normal on the gauge, above 4000 rpm with the stock valve. It jumps over 10-15 psi, real fast, normal was 2-4 psi. This extra pressure will loosen side cover bolts. All that pressure under the piston slows it down, and rpm wont climb anymore.
if you remove the stock valve, the pressure goes even higher at lesser rpm.
I started installing 2) 1 way check valves outta the valve cover and removing the stock valve. I never see pressures over 8 psi at 5900 rpm anymore.
Give em a try, you will see.