USD Forks

Stereordinary wrote:

Yep, that's exactly what I did. Here they are naked away from all the other bits. Exact same part left to right.

 

I love the CAD work - I am still scratching drawings on scraps of paper with a pencil   about my limit is 2D in excel 

Stereordinary wrote:

Wouldn't it not be able to do that anyway, because it's captive by the axle collars?

It's impossible for the wheel to float if the spacers are registered against the immovable fixed points of the fork inners and it removes any side loads from the collar arrangement which could cause movement even though the collars have the stepped locating lips.
It's just my belt and braces approach and maybe over cautious but i feel would be good engineeing practice to do it that way and then the whole assembly is locked in.

 

I get ya. Currently I have the speedo drive on the left, and there's no leftover space on that side. The right side spacer however I think could be made larger because of what you're suggesting, but also I think it would look better. More even visual distribution on each side. Maybe I could even contour it similar to the speedo drive for symmetry. 

Made this little overbuilt 2x4 stand to hold the front of the bike so I can take the lower triple out for measuring. 

Whelp, I got the spacers in today and they’re screwed up. It’s my fault, should’ve measured more carefully. Pretty sure there’s no way to modify them to work either. Live and learn I guess. Is there really no one here that can help me with 3D printing for prototypes? I’ll pay, not asking for favors. 

Might be able to save the adapters after all. More on that later.

I wanted to ask if anyone has an opinion on materials for the lower yoke. Stock on the Zephyr is steel, while the ZX6R is alloy. It seems like alloy would be the more upscale way to go and I believe it would be less expensive. I have reservations about it though, because I would need some kind of mechanical means of clamping the stem into it. If I make it out of steel on the other hand, I could have the stem welded in for a sure bond. I'm inclined to do that, not just for the security of mating the two pieces together, but also because I have a little more faith that a steel part will be strong and won't ever break on me. I could have it made from something like 4130 steel as well, so while it may not be as light as alloy, it could potentially still be lighter, or at least not much heavier than stock. What do you gentlemen think?

Alloy is fine (my ZX6R stem is alloy) it is press fitted into the bottom yolk so no "mechanical fixing" or welding required (remember when the yolks are clamped to the forks above and below the neck the bottom yolk can't go anywhere) 
PS: the factory alloy bottom yolk is "cast" and it's "hollowed out" on the underside whereas I assume you are planning to use solid billet so it would be far stronger than a stock item (they are designed that way so they would "give" in a moderate frontal impact to reduce the risk of bending the frame)

Interesting! I assumed they were hollowed out for weight relief, and because totally solid isn't necessary. I was planning on designing the top one solid for simplicity and cost savings (less machining), but the bottom one hollowed out to some degree for weight. But I suppose making them both solid would make my life a lot easier. 

Stereordinary wrote:

Interesting! I assumed they were hollowed out for weight relief, and because totally solid isn't necessary. I was planning on designing the top one solid for simplicity and cost savings (less machining), but the bottom one hollowed out to some degree for weight. But I suppose making them both solid would make my life a lot easier. 

The weight saving would be negligible. Most vehicle manufacturers engineer in weak points (crumple zones in cars etc) car suspension arms etc are designed to bend in a curb impact rather than damage the chassis. However trying to replicate this requires a great deal of specialist structural engineering knowledge so the safe bet is "billet"  

Have you thought about contacting PDM Fabrication? This is exactly the kind of work he does, and he is a forum member. There is a link at the bottom of the page.

Wookie58 wrote:

Most vehicle manufacturers engineer in weak points (crumple zones in cars etc) car suspension arms etc are designed to bend in a curb impact rather than damage the chassis.

I knew that about cars, but didn't know it applied to motorcycles in any way. Learn something new everyday.

TexasKZ wrote:

Have you thought about contacting PDM Fabrication? This is exactly the kind of work he does, and he is a forum member. There is a link at the bottom of the page.

I have ad blockers on all the time, so I was unaware. Thanks, I'll check it out.

Rethinking the top yoke, I wanted to try and make it as flat and simple as possible to save on what it will cost to have machined. Figuring I could extend the forks as discussed earlier in this thread. However then I remembered that the top caps will be too tall and make contact with the handlebars. Render image is below.

So my question before I go with the original plan of a dropped top yoke is if there are aftermarket replacement top caps with less height? Like even if it's a pre-set sort of deal where I get a certain size for them to set preload, but then the they are no longer adjustable. Or, if a complete replacement cartridge kit might achieve that?