NC 4-Speed Kickstarter Mechanisms

[double diamond]

The posts by hobby on 4-speed kickstart mechanisms reminded me of some of the differences. There were two 4-speed transmission designs. The earlier employed a caged ball bearing on the left end of the output shaft. The second design converted to loose rollers similar (although not identical) to the 5-speed design. As a consequence of this design change, there are different kickstarter parts for the two 4-speed transmissions. I’m attaching pics of parts for the two 4-speed designs and a 5-speed mechanism for comparison. Components are identified in comments. Hope this helps in identifying the parts you are in need of to get your kickstart mechanism straightened out. Since I can only post five pics, I'll add another post for the rest.

Matt

[double diamond]

Here are the rest of the kickstarter part pics:

[DewCatTea-Bob]

____ First of all Matt, THANKS-a-lot for all your rather extensive good-work & nice-consideration for bothering to post this thread you've created !!
It's quite nice to have our members contribute as you have, now & in the past !



[quote= double diamond ...
" There were two 4-speed transmission designs. The earlier employed a caged ball bearing on the left end of the output shaft. The second design converted to loose rollers
As a consequence of this design change, there are different kickstarter parts for the two 4-speed transmissions. "

____ It seems you have overlooked that you've put the 'cart-before-the-horse',
as the "consequence" was actually the other-way-around...
Ducati primarily desired a 50% increase in the number of engagement-teeth between the ks.gear & 1st.gear,, and to (rather cheaply) do that, they then consequently had to modify their previous simple ball-bearing support-setup and update to their later roller-bearing setup.



" I’m attaching pics of parts for the two 4-speed designs and a 5-speed mechanism for comparison. "

____ Lots of good-work Matt, thanks for that !
However your picture posting-organization, (as it has turned-out), could use a little help,, and all the pics themselves are a good-bit on the smallish-side to see very well (with their one click limitation). _ So I've done some organization & enlargement work with them, as can now be seen down-below.
__ BTW,, there's also two (uncompatible) types of n-c.5-speed starter-gears, as well !



" Hope this helps in identifying the parts you are in need of to get your kickstart mechanism straightened out. "

____ My-guess, (without seeing any pix of exactly what 'hobby' has), is that he probably needs the ks.gear that's seen pictured in the center-position (of either pic.set I've posted).


Duke-Cheers,
-Bob

[double diamond]

A few more comments on the kickstart mechanisms, since I was in something of a rush with the first post. The 5-speed mechanism has involute profile gear teeth, the 4-speeds just have near-flat profile teeth. The 4-speed kickstart shafts have a smaller diameter bearing journal than the 5-speed where they fit in the bushing in the center case. The ball bearing design appears to be basically a carryover from the 200 bevel single, so these parts may be common between the 200 and early 250 but I believe the kickstarter shaft may be shorter on the 200. I haven’t verified any of this though. I would expect the Diana Mark III that hobby has been dealing with would employ the roller bearing 4-speed design. Another way to identify the design is that the ball bearing kickstarter mechanism will be installed in engine cases with the engine number stamped on the left case half and the “DM250” on the right case half. Roller bearing first gear was identified by engine ID numbers in reverse position. I’m not proud of the pics, taken on my cell phone since my $400+ Nikon digital camera finally expired. But they do adequately show the differences, especially with Bob’s enhancements and organization. The variety of minor design changes to these bevel singles through the years is actually rather daunting if one is trying to piece together a dis-assembled motor. I recently assembled a 200 motor that included new valves. When I tried to assemble the new valves (which at first glance appeared to be identical) with the old keepers, it turned out the keeper groove taper on one of the replacement valves was different than the original valve. Situations like these are the likes of which hobby has encountered with his Diana Mark III unfortunately frustrating his entry in the Giro.

[machten]

Matt... just as a holding point at the moment and recognition of some important help...many thanks for taking the trouble to publish your posts. Your last post helps a hell of a lot. Thanks!

Kev

[hobby]

What great help Mat for these details. I will now start pulling it all apart again and with the help of your pics try and figure out what it is what I have here. Then comes the fun in trying to find the right parts to make it all work. I have since send my silver shotgun and 450 yellow deso to Europe to ride in the moto giro instead of the 250. As they say "shit happens"
Again many thanks to everyone that has contributed in helping me out.
Paul/hobby

[hobby]

I will post some pictures of what comes out of the engine as soon as I have it apart
Paul

[DewCatTea-Bob]

[quote= hobby ...
" I will now start pulling it all apart again and with the help of your pics try and figure out what it is what I have here. "

____ You've mentioned kick-lever slippage...
Well the mismatched pair connected by the RED-line*, would not only slip,, they obviously wouldn't even begin to grab !
So it must be as previously suspected,
you most likely have been trying to match-up the particular gears connected by the BLUE-line*.
(* See added pic below.)


Hopeful-Cheers,
-Bob

[machten]

Matt & DCT Bob,

Paul and I had an opportunity to pick up some 4 speed and 5 speed kickstart parts yesterday. Your pic's and advice has been most useful in that. Special thanks to Matt for his dedicated work with the photos, layout and description (I was magnifying them on my iPhone), and DCT Bob for his further detailed explaination.

Thanks Guys,

Kev

[machten]

As a little personal bonus on that visit with Paul, I picked up a set of headlight ears for my 68' Mark 3 250 Desmo twin filler. Mine had been drilled for indicaters by a PO and I'd been looking for while. They cost me AU$40. There's another set the same and also a set I suspect is for a 175 Sport or related narrow case (for clipons - slotted headlight holes) if anyone is interested.

IMG_1363.JPG

Kev