Hey Folks,
I have been getting better with the TIG welder recently and I believe it's time to stiffen up this RD350 frame a bit. Is there any established thinking on where/how to add metal to maximize stiffness? I have seen a variety of things done on similar bikes at the racetrack and haven't been able to discern any best way...
Thanks in advance!
Triangulation is usually what people attempt. Your chassis is only as strong as its weakest point, that includes the entire system of components. In there is some natural frequency that represents how the chassis responds to inputs not mitigated by the suspension. Which is an important but total black art that I have no idea how professional race bike designers try to manage (this problem is a lot more simple on a racecar).
Anyways, long story short, probably add some gussets. It will be fine. 1" Japanese tubing from 50 years ago isn't exactly the state of the art. I did a removable aluminum large OD sub frame for the rear shocks on my 350, it handles great, but it was a ton of work and not even remotely necessary.
Replacing or adding bracing to the swingarm would be my starting point. imo the stock one will move before the frame starts to flex.