I’m using exhaust tube. Quite strong enough for what I want. The bends were quite easy and by adding a few plate and posts to the jig, I could do a mockup and it looks good. I’ve partially modeled the motor in the frame with CAD but today I though I might see if it fits. With good photo, a bit of cut and paste was used for the photo below and it looks close. I may have to change the head studs for bolts as you can see from the photo, there is no room to lift the head. It will have to slide out. The motor has to be tilted down a bit in the front but as it is a 2 stoke, it won’t matter. The motor looks quite balanced in the frame.