Originally Posted by MEASURE TWICE
Is that a tube at the top of the head bolts maybe? It melds with the exhaust tube for support?
Yep. It's slightly larger tube than the primary pipe, I cut it in half lengthwise and flattened the end with some grinding to fit, and then cut a d-shaped flat at an angle into the back end of it to give a gripping surface for the hose clamp. It feels very solid and nothing has loosened up in 2 heat cycles (driving 15min and letting cool).
I'm determined to get the most out of this motor before I upgrade. Next mods:
1. Grind the plastic camshaft (have extra). Remove ~.030" radius from base circles and weld/.030" onto the lifters... Get some more lift - CURRENT LIFT is .157" from measuring the cam
2. Upgrade to a larger carburetor with a straight shot intake.. I'll get rid of that s-manifold I think I'm losing power cause of it
3. Advance timing 4deg- going to fabricate a plate that moves the magneto approx .220"
4. Increase compression further to where I have .020" valve clearance, maybe open up the transfer into the cylinder in the head
Bike mods- new design 2-speed (delete one js, delete two chains)
The current 2-speed while works, is difficult to adjust and keep it aligned. It's out of alignment frequently and I get fast wear in my chains and the power loss is noticeable on the top end. It isn't strong enough but I've proven the concept on this bike. Currently tops out around 45 on level ground. I wanna bump that to 50. It's still a legal displacement and hp for CA Mbs.