Xs500 project

So what happened to the original front hub? It is preferred over the 350 piece because you can reverse your forks and place the caliper behind the leg and still use a cable speedo. I see you have the forks mocked that way so if you are not using a cable speedo it does not matter of course. That is a wide rim for the front. Bigger than a 90/90 x18 tire will slow down the handling. You will notice it.
 
Mobius, I am confused by your question. My bike is a Xs500 not an RD350 so the forks are installed in the factory orientation. I know that the rim is wide I’ve made a few rookie mistakes with this bike but it is far from being complete.
My intentions were to run Dunlop 100/80/18 front and 110/80/18 rear on these rims but I’ve run into problems with the spokes and will probably not end up using the rims or spokes in the end.


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Painted and installed



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Uglyrabbit said:
Mobius, I am confused by your question. My bike is a Xs500 not an RD350 so the forks are installed in the factory orientation. I know that the rim is wide I’ve made a few rookie mistakes with this bike but it is far from being complete.
My intentions were to run Dunlop 100/80/18 front and 110/80/18 rear on these rims but I’ve run into problems with the spokes and will probably not end up using the rims or spokes in the end.

Sorry for the confusion - My error. I confused your bike with the earlier TX500 that has nearly identical spoke wheels to the same years RDs. Those bikes have the caliper mounted in front of the fork legs. The 500 had an option for a second disc, so it had mounts for the second caliper and disc. Because of this you could flip the forks to move the calipers behind the legs without also flipping the wheel and thereby keeping the speedometer drive going the right way round. Because the hub with the second disc mount interchanges with the RD hub, you could flip the forks on your RD and swap out the hub for the 500 hub and retain the mechanical speedo drive. This moved the disc to the other side because the RD legs only have the caliper mount on the right leg so flipping the forks moved the mount to the left. Alternatively, you could swap out the right RD leg for a left 500 leg, mount the caliper on the right side behind the leg and keep wheel unaltered.
If you are wondering why this is getting so much attention, it is because moving the caliper(s) behind the leg is a genuine performance upgrade. Those cast iron calipers are crazy heavy (the road race version was identical but aluminum) and moving it behind the fork leg moves it a lot closer to the center of rotation of the steering. This increases the natural frequency of the whole steering assembly. The higher the natural frequency, the higher the speed needed to start the assembly resonating, commonly referred to as speed wobble. Being that it was(is) quite easy to get your RD to go considerably faster than originally intended, speed wobble is a problem and part of the solution is to move the speed wobble to a higher speed - hopefully higher than you can make the bike go. You can do that by reducing the moment of inertia which increases the natural frequency. And that can be done by either reducing the mass of the assembly, or moving the existing mass closer to the center of rotation. So light and close to the steering pivot is the goal. This applies equally to your 500, to all motorcycles specifically and all things in the universe in general. You can also see why a lighter wheel and smaller and thereby lighter tire works toward this goal as well.
 
jpmobius said:
Sorry for the confusion - My error. I confused your bike with the earlier TX500 that has nearly identical spoke wheels to the same years RDs. Those bikes have the caliper mounted in front of the fork legs. The 500 had an option for a second disc, so it had mounts for the second caliper and disc. Because of this you could flip the forks to move the calipers behind the legs without also flipping the wheel and thereby keeping the speedometer drive going the right way round. Because the hub with the second disc mount interchanges with the RD hub, you could flip the forks on your RD and swap out the hub for the 500 hub and retain the mechanical speedo drive. This moved the disc to the other side because the RD legs only have the caliper mount on the right leg so flipping the forks moved the mount to the left. Alternatively, you could swap out the right RD leg for a left 500 leg, mount the caliper on the right side behind the leg and keep wheel unaltered.
If you are wondering why this is getting so much attention, it is because moving the caliper(s) behind the leg is a genuine performance upgrade. Those cast iron calipers are crazy heavy (the road race version was identical but aluminum) and moving it behind the fork leg moves it a lot closer to the center of rotation of the steering. This increases the natural frequency of the whole steering assembly. The higher the natural frequency, the higher the speed needed to start the assembly resonating, commonly referred to as speed wobble. Being that it was(is) quite easy to get your RD to go considerably faster than originally intended, speed wobble is a problem and part of the solution is to move the speed wobble to a higher speed - hopefully higher than you can make the bike go. You can do that by reducing the moment of inertia which increases the natural frequency. And that can be done by either reducing the mass of the assembly, or moving the existing mass closer to the center of rotation. So light and close to the steering pivot is the goal. This applies equally to your 500, to all motorcycles specifically and all things in the universe in general. You can also see why a lighter wheel and smaller and thereby lighter tire works toward this goal as well.




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I haven't posted on the board in a while... But it was cool to spot a Yammy 500 build right away. I like how you decided to run spoked wheels, like myself, but I was surprised to see a rear drum where a disk used to be. I was adamant that I wanted to keep spoked wheels on my 500 as well, but where mine came with a drum, I had to have a disk. In my case, I have a YZ250 disc brake rear hub laced to an 18" black anodized rim. But I'm sure you can see all that if you feel like perusing my build thread.
But I digress. Your choice to run spoked wheels on a bike that came originally with mags is quite inspired.
 
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