Job done!
Re top nuts. My slightly domed a10 top nuts were found to be quite tapered on the inside which prevents a nut easily sitting square against it on the inside (see pic). So no luck with John’s blingy street-cred dome nut look for me
. Instead, the early a65 top nuts (pn 97-2652) fit fine and have a 5/16” CEI thread into them (Jules: it is 5/16”, not smaller). Using 10mm threaded rod, I used John’s trick of starting to cut the thread in the lathe to get it dead straight, then finished it with a die.
Re the overall length of the dampeners. The original post using the Dow spec says 16 11/16 whereas other say 19” works. I made mine 19” (482mm) and measured as follows:
Using standard 22 1/2" length stanchions and with the fork leg fully compressed I measured 530mm (20.8”) from the top of the stanchion to the bottom lug. See the pic. So, there is no way these can bottom-out. This all fits with what Peter says above. In fact the dampener could even be a bit longer but there is probably no need and it may get in the way of the 2 bleed holes in the stanchions – I didn’t measure for this.
With respect to the oil depth, with 215ml fork oil and on the centre stand, the depth from the top of the stanchion to the oil level was 455mm (approx. 18”). But the top nut sits about 8mm higher than the top of the stanchion - due to the taper gap at the top of the top yoke, the speedo mount plate and the washer under the top nut. So my dampeners should be immersed at least 482-455-8 = 19mm (3/4”). When I checked, the volume of the dampener valve also displaced some oil and it was well wet at least 2/3 the way up the valve body. Off the stand and on the road the valve will be further immersed.
So: early A65 nuts work fine and make threading easy. 19” overall length gives plenty of clearance.
I’m trying 10W oil and on one quick test ride it feels about right for me – much less spongy than without the dampeners. I’m looking forward to proper ride when it stops raining. Thanks again to John for this great thread.