I have had to have anew front rim laced to my hubin my 1974 850 and have two problems;
1] When I refit the original stanchions, in the yokes, both top nuts bottom out on the bottom of the threads [with washers in place]inboth stanchions. Thisallowsabout 5mm lift on both stanchions [before the yoke pinch bolts are tightened]. I suspect the frame has been changed because there are no frame numbers anywhere. I presumethe previous owner orrepairer tightened the top bolts, the stanchions slide downwards then the pinch bolts tightened! I assume either the top nuts or stanchions are wrong or both. Is there any way I can tell which. I need new stanchions but I don't want to repeat the same assembly mistake.
2] I refitted the forks and new wheel rim andmeasured the distance from each fork leg to wheel rim and run out [as best I can]. On the disc side distance to fork leg is 31.77mm [using my non digital Vernier caliper]and run out 0.5mm using an old set of feeler blades. The non disc side distance to fork leg is 30.4mm and run out 0.6 [thedifference in run out, from side to side, is presumably down to the manufacture?]. Are these readings acceptable? I don't want to go back to the wheel builder only to told not to be so stupid.
Many thanks for any help. Roger
Are you using the std spee…
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Previously john_holmes wro…
Previously john_holmes wrote:
Are you using the std speedo and tacho mounts/holders that the fork top nuts pass through, if not then you need shorter nuts as the std nuts are designed to pass through the holders and are longer by that amount. Without the holders they bottom out in the thread in the stanchion before the stanchion is pulled up into the taper fully.
On the rim that may be acceptable (60 thou or 1.5mm is sometimes given as a guide) but I try for closer when I do mine but always ignore the weld as you can never trim that out, so if your run out includes the weld area I would do it again and give the run out excluding the bump caused by the weld. I try for 10 thou run out but if I end up chasing it around then I settle for 25 thou. Again ignoring the weld.
On the gaps to the legs I would be looking to even those up but with a disc front it may be a fruitless exercise as the spokes on the rim side are virtually vertical and tightening them moves the rim very little, the factory service sheet recommend hitting these spokes with a rubber mallet next to the hub to get them to pull over more. You are looking to move it over 0.65mm so leave it be unless you have experience but on a normal wheel you would slacken the non disc side one 1/4 turn and the tighten the disc side 1/4 turn and then check, repeat until correct. But as I have said this is not an easy rim to get right.
Hi John, I am an idiot I forgot to put the speedo/tachometer plates in place!!!!!
I think I will speak to the wheel builder about your comments.
Thanks for you help. Roger
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If you have enough clearan…
If you have enough clearance between the disc and the fork slider, you could consider machining off 0.685 mm from the disc side spacer to centralise your wheel. (thats about 26 thou in old money) the run out of 0.5 and 0.6mm (20-25 thou) is pretty good IMHO
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Are you using the std speedo and tacho mounts/holders that the fork top nuts pass through, if not then you need shorter nuts as the std nuts are designed to pass through the holders and are longer by that amount. Without the holders they bottom out in the thread in the stanchion before the stanchion is pulled up into the taper fully.
On the rim that may be acceptable (60 thou or 1.5mm is sometimes given as a guide) but I try for closer when I do mine but always ignore the weld as you can never trim that out, so if your run out includes the weld area I would do it again and give the run out excluding the bump caused by the weld. I try for 10 thou run out but if I end up chasing it around then I settle for 25 thou. Again ignoring the weld.
On the gaps to the legs I would be looking to even those up but with a disc front it may be a fruitless exercise as the spokes on the rim side are virtually vertical and tightening them moves the rim very little, the factory service sheet recommend hitting these spokes with a rubber mallet next to the hub to get them to pull over more. You are looking to move it over 0.65mm so leave it be unless you have experience but on a normal wheel you would slacken the non disc side one 1/4 turn and the tighten the disc side 1/4 turn and then check, repeat until correct. But as I have said this is not an easy rim to get right.