rebuild gear selector box

[flynbulldog]

I did a search but only found a little info on adjusting the selector, does anyone know of a thread or other information on how to properly assemble the selector box?
Maybe some good mods? (for example: I'm using a fork from a later 450 box, it's much more robust and precise)
Thanks

[DewCatTea-Bob]

" Maybe some good mods? "

____ The shifter-box mechanism is something that I've spent considerable experience with ! ...
So I once had compiled a list of mods which I-myself came-up with that seemed to help-out (with it's intended function) a fairly worthwhile amount. _ I don't now recall them all but, one mod was to replace the stock-sized ball-bearing with the next smaller size -(1/4" I believe). _ The purpose was to help the selector to become better locked into it's chosen selection-place/position & stay so set more securely. _ The down-side being that slightly increased foot-pressure would then be required to perform a foot-shift.
As well as the smaller steel-ball, I also shimmed-up the ball's stock coil-spring with an equal dia.sized washer (for intensifying the same purpose). _ (In fact, I tried that idea before trying the smaller ball.)
Another mod was to replace the stock coil-spring which presses the selector-fork against the selector-wheel...
I had discovered that the stock spring seemed to press the fork TOO HARD against the wheel's pegs, thus at times the fork would become hung-up over a peg (instead of quickly falling-past the peg as intended), thus leaving the selector unprepared for the very-next soon to follow shift-effort. _ (If not shifting in a big-hurry, engine-vibration most often gets the hung-up fork tossed-over into intended place.)
So in THIS case, use of a WEAKER coil-spring then allows the (somewhat weak) return-spring to more easily reset the selector-fork properly back to it's regular/normal-position (with less resistance to doing so, as the fork gets pressed-over the pegs by the return-spring -[which could've been made a bit stronger !] !).
I found such weaker coil-springs (otherwise just like stock), at a local spring-manufacturer, but before that, I'd simply cut-off a length of the stock-coil (making it a little shorter & weaker).
__ I should point-out that most-all such selector-mods are not really needed when all the involved stock shifter-parts are as new,, and that I only found that my mods were of any usefulness for shifter-mechanisms which had become well worn & thus loose -(with much increased fit-tolerances), which is a fairly common issue (that Ducati was not unaware of & tried to address).
____ After I recall any other related mods which I had ever found of any good use, I'll add them later.


Dukaddy-DUKEs,
-Bob

[Jordan]

Do you want info on adjusting the assembled selector box?
There's some recent talk here on this topic.

Jordan

[flynbulldog]

Hi jordan, yeah I saw the thread on adjusting the selector box. I'll get into that if I have a need after the bike is running. and, thanks very much Bob for your insight.

I tackled the job of putting two selector boxes back together today. They actually weren't too bad once you get the selector spring loaded. After a couple of attempts I got pretty good at it.
One of the boxes had an early (63?) fork that was cracked and misaligned - (now I'm wondering if that engine is a 4 speed???) I put a different fork in it with a cross-bar
and in the second box I used a HD fork out of a 450 that is hinged.

All of the parts were cleaned and dry, in the first box I greased the areas that had contact and then oiled the rest of the parts to avoid rust, but I noticed that the oil was starting to clean the grease away from where it was needed so I had to pull the box back apart and wipe it all down and re-apply the grease. On the second box I tried to lightly smear grease on all of the parts and didn't oil anything.
I hope I have adequate lube in there...

They both seem to work pretty good but I didn't count the number of clicks (gears) I am missing one of the screws in one box. I hope I can find something close at the hdw store

(BTW, yes I'm building two engines. One, i believe, is a 63 and the other, a 67 - both from scramblers)

[DewCatTea-Bob]

" One of the boxes had an early (63?) fork that was cracked and misaligned - (now I'm wondering if that engine is a 4 speed???) "

____ The 4-speed version has a selector-wheel with one less peg !


" I hope I have adequate lube in there... "

____ Merely allowing each part to self coat with heated grease, is sufficient,, as the main concern is to avoid rust.
__ I once read where someone had installed a grease-serk (somewhere on the box), so they could then force-feed the box FULL of grease...
I don't recommend doing that !


" They both seem to work pretty good but I didn't count the number of clicks (gears)
(BTW, yes I'm building two engines. One, i believe, is a 63 and the other, a 67 - both from scramblers) "

____ If your "63" is a real 1963-model, then both DUKEs will have 5-speed boxes !


Duke-Cheers,
-Bob

[flynbulldog]

Thanks Bob.

The two engines that I have are Ser. no.s 98946 and 91454. I believe they were both in scramblers but I don't know for sure about the early engine.
Looking at the numbers listed on the BH site I thought them to be a 1967 and 1963. Can you give me any further insight?

(BTW I didn't think to count the pegs when I was putting them together - I just didn't notice)

[flynbulldog]

After doing it it doesn't seem that difficult but I have some photos of the selector box assembly if anyone would like to see them.
Let me know and I'll post it up with a description. maybe some of you can tell me if I made a mistake.

[DewCatTea-Bob]

" The two engines that I have are Ser. no.s 98946 and 91454.
I thought them to be a 1967 and 1963. Can you give me any further insight? "

____ Well the one starting with 98 was no-doubt produced in 1966 but was likely called a 1967-model, the n-c Scr.models were replaced with wide-case versions that year !
However the motor starting with 91 was produced either in late-1965 or early-1966, and was probably sold as a 1966-model. _ It's motor-number is fairly close to the point when the '65-models were replaced with the distinctly-altered '66-versions. ...
Have you checked-out any of the past threads which cover the differences between the two somewhat varied Scr.models ?
The biggest change/difference between the older & newer n-c Scr.motors is the type of alt.stator employed.
__ Do you have any means to check your alt.circuits ?


" I believe they were both in scramblers but I don't know for sure about the early engine. "

____ The quickest way to determine if a motor-case was ever a Scr.model, is to look for a 6mm-hole made through the top-center (at an obvious raised-point) of the protruding inlet-cowling for the drive-chain.
That hole was made for the upper mounting-point of the internal steel chain-guard, which was added just for the n-c Scr.models only !


" (BTW I didn't think to count the pegs when I was putting them together - I just didn't notice) "

____ That was probably because both are the same.



Duke-Cheers,
-Bob

[flynbulldog]

well, despite the numbers being so far apart it looks like they could both be 66's... haha.

I have no way to test the alternators although I just removed the flywheel and stator from the late engine. I will be running it as a total loss system.
The early engine was in parts with a big box of mixed pieces, I tried to grab everything I could find to make a complete engine when I bought it.
I later found that the flywheel I grabbed is off a widecase so I don't have a flywheel or stator for the early engine.

according to your criteria both are from a scramblers as both have the chain-guard still in place.

I ended up with a few spares; a head, valve covers, cylinder, clutch basket. a couple good cams. But I'm missing two head bolts.
If anybody has two 250 nc head bolts they could spare please let me know.

[DewCatTea-Bob]

" well, despite the numbers being so far apart it looks like they could both be 66's... "

____ Possibly so, however while the newer one certainly is a '66, if the older model has leaf-springs (instaed of a coil-spring) for it's starter-gear, then it's a '65.


" I have no way to test the alternators although I just removed the flywheel and stator from the late engine. "

____ I trust that you first took note of the flywheel's preexisting timing-position, prior to it's removal from it's place on the crankshaft ?


" I will be running it as a total loss system. "

____ Why, exactly ?


Duke-Cheers,
-Bob