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First post.. Gear selector drums.

Posted: Thu Aug 28, 2014 1:20 pm
by Ian B
Hi all, I've just 'inherited' three Ducati singles that were stripped down 17 years ago and stored in someones attic. There's a Diana with no original tinware, a 350 Sebring which I think is all there and a 250 race bike, all are narrow case. A lot of the restoration work was started and many bits were polished and plated and a few bits powder coated. There's a bag with all new bearings and many other engine spares including 3 barrels, 5 cams and a couple of cranks. Once I've built up the engines and have them running I'll list some of the spares to see if anyone needs them.
Anyway, back to the post! The gear selector drum for the 250 race bike has a selector drum that someone has obviously spent hours on grinding away excess material to save a whopping 50 grams. Is there any other reason to do this other than weight saving as I can think of many easier ways to save such a small amount?
The one on the left is ( i think) standard 5 speed, the middle is the modified 5 speed and the right one is standard? 4 speed.
I'm sure I'll be needing plenty of help from you all in the coming months when I get fully into the rebuilds.
Selector drum.jpg

Re: First post.. Gear selector drums.

Posted: Thu Aug 28, 2014 2:56 pm
by Jordan
With no positive stop provision, an advantage of a lightened selector cam is less inertia, so less tendency to overshoot to a false neutral if quick changes are made - in theory anyway.
Someone described a simple way to get positive stop on a bevel Ducati, with an addition to the selector box.

Re: First post.. Gear selector drums.

Posted: Wed Sep 03, 2014 3:31 pm
by Ian B
Thanks for the reply Jordan, I hadn't thought about the inertia problem. Is the 4 speed better in this respect then as it's so much lighter?