frame bracing

Toad,

An engine mount kit can take a lot of slop out of a stock frame. The kit I'm using is from Pingle. The engine castings and frame will need to be drilled and reamed for correct fit, it's worth the work.

kidkawi,
a stiffer swingarm can make a world of difference in the handling of these old bikes and does not require frame mods.
leon


p.s. i have made several frame brace kits.

Some of that bracing looks like overkill. The two frame rails that bend around the front down tubes are welded to the down tubes, creating a triangle, so that plate is not needed IMO. I think most of the flex comes from behind the engine, not the steering tube.

the awesome thing about building your own bike is you can use or not use whatever you like.
if you don't think a brace is necessary don't use.
if you like the way a stock swingarm looks,use it.
if you get tired of unwanted lane changes when you hit a bump mid corner,get a stiffer swingarm and maybe try some frame braces.
it is ultimately your decision.

i made mine when i cut out the frame braces you see.

leon

www.speedwaymotors.com/1932-Ford-Frame-C...ing-Plates,7531.html
Hot rodders learned a long time ago that it doesn't matter how big of a motor you shove in a model A ford or how fancy of suspension/axles/brakes you stick under it .
If the frame bends like limp noodle everytime you hit the gas or jump on those big brakes at some point youll find yourself in deep $hit because of it at the worst possible moment! :woohoo:

Kidkawie wrote: Some of that bracing looks like overkill. The two frame rails that bend around the front down tubes are welded to the down tubes, creating a triangle, so that plate is not needed IMO. I think most of the flex comes from behind the engine, not the steering tube.

if your bike handles anything like mine the overkill is much appreciated :lol:

plus if i know im building a bike to 160 to 200 hp i want the frame and everything else to be capable of twice that. overkill is bliss

Racing is one thing, I'm talking everyday street riding/cruising. I could easily throw a crapload of gussets on my frame and call it a day, I'm looking for someone to find exactly what the problem is with the older frames. Like I said, riding it seems like behind the engine is the weakest spot, possibly where those triangular gussets are above the swingarm bolt.

I guess the only way to really find out is to put a bare frame/engine in a jig and tray to fold it in half.

Kidkawie wrote: Racing is one thing, I'm talking everyday street riding/cruising. I could easily throw a crapload of gussets on my frame and call it a day, I'm looking for someone to find exactly what the problem is with the older frames. Like I said, riding it seems like behind the engine is the weakest spot, possibly where those triangular gussets are above the swingarm bolt.

I guess the only way to really find out is to put a bare frame/engine in a jig and tray to fold it in half.

i think alot of it was inconsistent headtubes and welds then the flimsy swing arm and undersized motor bolts mostly

Kidkawie wrote: Racing is one thing, I'm talking everyday street riding/cruising. I could easily throw a crapload of gussets on my frame and call it a day, I'm looking for someone to find exactly what the problem is with the older frames. Like I said, riding it seems like behind the engine is the weakest spot, possibly where those triangular gussets are above the swingarm bolt.

I guess the only way to really find out is to put a bare frame/engine in a jig and tray to fold it in half.

AUTO CAD....(COMPUTER AUTOMATED DESIGN) program would let you enter KZ or Z1 frame diamentions and profile into computer. It will let you imput dia of tubing ID and OD. You can apply stresses to frame to see how it reacts. It will show all stress / weak points of frame in a different color with red showing stressed area. It then lets you goto a single stress point and introduce different remidies to correct problems....IE,,, tubing or plates.....when done right the color of area will change from red to blue and tell you the amount of correction.....it is 99% correct and is all done on computer screen....you can move frame in 3 axis and in any direction and look at it.....the whole frame can be done and area corrections printed out. Its an incredable process.....only problem.....the thousands of dollars the program costs and the skill needed to run program. If you never have seen the process.....it would blow your mind. This is the best way period....to access a frame and its weak points....you can see below the stress in red....also the forks and frame are autocad imputs....you can see how real it is....you can design any frame you want and know how its going to react before built.

That's what I'm talking about.

Racing is a different ball game. Yes, if I was going to race a bike, I would gusset the shit out of it. But I think with some fine testing (or that CAD program) someone can figure out the actual weak point/flaw in the frame (if there is one) so the average guy doesn't have to pucker up doing 80mph.

enjoying this discussion guys. In my mind having worked as a mechanical designer/design engineer for years using 3D CAD software. its apparent the factory already did a lot of analysis to the frames from the 70s and fixed everything in the 80s frames and modified everything in a way very similar to what blackbanshee shows in his pics. at least as far as the handling for the street goes. its shows when you look at the frames next to each other...





I wouldnt think to add much more to a factory frame than what they did. Of course if I ever had time enough at work (ha!) I would love to measure out both frames, build some 3D models in Pro/E and get one of the FEA guys to run 'em thru a few of they're analysis programs like Hypermesh and Ansys.

cadmonkey wrote: enjoying this discussion guys. In my mind having worked as a mechanical designer/design engineer for years using 3D CAD software. its apparent the factory already did a lot of analysis to the frames from the 70s and fixed everything in the 80s frames and modified everything in a way very similar to what blackbanshee shows in his pics. at least as far as the handling for the street goes. its shows when you look at the frames next to each other...

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I wouldnt think to add much more to a factory frame than what they did. Of course if I ever had time enough at work (ha!) I would love to measure out both frames, build some 3D models in Pro/E and get one of the FEA guys to run 'em thru a few of they're analysis programs like Hypermesh and Ansys.

That would be awesome if that was done....thanks for checking in on thread. Thanks