> Norris Hall Wrote:
> I just had this exact same problem on my Motobecane. The races are
> threaded onto the inner tube and just needed cinching up a bit. It can
> be tricky to wrap your head around because from the outside they don't
> look like anything but a bushing but they are actually threaded nuts
> that are used to take up the play between the upper and lower bearings.
> I know your design is probably different but thought it might help
I understand. I don't think that is the issue. Not sure about Motobecane, but Puch has a somewhat crappy design here with regards to the fork yokes, especially the top yoke.
I believe the main tube is welded to the lower yoke. You drop a ball race in down the tube, you drop your balls and cage in, grease em up. Next comes the female tube in the frame. That has the upper race friction fit (tightly) into the female tube. Push the male tube/yoke/fork assemly up into the female frame tube. The weight of the moped holds that in pretty good.
Now we move to the top of the female frame tube. We have a friction fit lower ball cage. Grease em up. Next the balls and cage. Grease em up. Then we have a top bearing cage/cup. Then a flat washer, then a threaded adjustable retainer. THis allows you to adjust the "squeeze for both sets of bearings top and bottom. At this point, the fork shocks are dangling above and the male fork tube is poking up throug the frame. There is still a bit of slop here, as the tube can move slightly in any direction, 360 degrees.
You now put the top yoke on. Put the two bolts into the yoke to hold the upper shock tubes. Now there should be a THIN flat washer on the main male fork tube, and finally the Chrome threaded top cap. All well and good.
I think the design is a bit of a fail, as there is nothing positively holding the upper yoke to the bearing assembly, it is dependent on pressure. Flat plate on smooth surfaces (washers), allows it to move. If the hole in the yoke is elongated in any way, it is subject to slopping around. There should be a more substantial mechanical connection to the fork tube assembly, or the upper yoke should be thicker/more substantial to avoid deformation and allowing a positive clamp force.
What is the recommended torque on the top cap bolt?