My first Duke (and my 1st post)

[DewCatTea-Bob]

" If I have a base diameter of 21mm and add 10mm lift, that's 10 on the radius - so the diameter is 41. "

____ I'm not sure I follow that math but, it turns-out with a clearance of .5mm, (and my-own good-math came-up with just .2mm).



" That's an interesting challenge for me. "

____ What would make it an easy shot to line-up, is if you could get a lite-up LED pressed-into the threaded-end of the shaft, and then look for it's light to show-up (at the shaft's opposite-end), in your camera-shot.
__ Regardless of the distance that you need your camera located at in order to get the best 'focused' shot (of the lobes), go for the best focus and set your camera to max.detail,, and if your picture then ends-up containing too-much side-ground, I'll then fix it for you (by zooming-in on just the cam).


Hopeful-Cheers,
-Bob
PS. Next I'm going to edit your last post merely so as to make use of the w.site's sw.program's quote-function.

[kaysystems]

I think the sleeved down cylinder version for Europe may have been small valve.

____ What "sleeved down" cylinder ?
The only sleeved-down cylinder I know of on any Duke-model was the late-175 model, (which was used for in 200-cyl.jugs).
__ If you're actually meaning to refer to the Mototrans (69x66)-250, THAT was actually a bored-out 200,, and yes that model would've employed the small-valves.

I remember that some of the widecase 250s were 236cc for the French laws, to keep licensing fees down. So there was simply a smaller liner & piston

David

[kaysystems]

Is this photo good enough? I used zoom to try to remove the close up distortion.

[DewCatTea-Bob]

" I remember that some of the widecase 250s were 236cc for the French "

____ Oh, right,, I didn't think of that engine... I've heard about it before of-course, but never had any particular data-knowledge about it and forgot of it.
__ I guess it's bore-size must've been 72mm (instead of 74mm).


Dukaddy-DUKEs.
-Bob

[DewCatTea-Bob]

" Is this photo good enough? "

____ Actually, it's more than good enough ! _ In fact, I believe that it's the best shot of the cam-lobe's profile that I've ever seen, (as it's the first time that somebody got their camera-lens all lined-up with the shaft-length so close to perfectly, that ya -(the viewer) can thus-then actually see all the way through the center-hole of the shaft ! _ Good-job !
____ Now-next, my comments about your pictured-cam.....
__ I gather that this must be your special-cam cuz I don't recognize it's lobes, as for one detail, it's lift-rate looks more radical, (which in-turn provides a greater 'average-lift'). _ Also, it appears that the ex.lobe (positioned on left) may have greater duration than the intake-lobe, (or at least a greater ratio of 'average-lift' vs 'duration', since it appears more square-shaped than the in.lobe).
However the intake-lobe appears more normally shaped (as compared to Ducati's wilder cams).
__ I thought it would be interesting to see this cam side-by-side with the known to be crazy-wild Vento-cam, so I've now posted them together (along with added comments), below.
__ With the picture on the left done so particularly-well, it's then actually possible to print-out the cam-picture and then take accurate measurements right-off the printout-page (using an accurate measuring device such as a dial-caliper, of-course) ! _ Also, the greater the picture-subject has been blown-up, the greater then is the accuracy of the taken measurements (off the print-out).

____ I think that's all I have on this topic, for now.


Enlightened-Cheers,
-Bob

[kaysystems]

" I remember that some of the widecase 250s were 236cc for the French "

____ Oh, right,, I didn't think of that engine... I've heard about it before of-course, but never had any particular data-knowledge about it and forgot of it.
__ I guess it's bore-size must've been 72mm (instead of 74mm).


Dukaddy-DUKEs.
-Bob

Don't think that many were made. A few made it to the UK. That's the only reason I heard about them.

David

[kaysystems]

" Is this photo good enough? "

____ Actually, it's more than good enough ! _ In fact, I believe that it's the best shot of the cam-lobe's profile that I've ever seen, (as it's the first time that somebody got their camera-lens all lined-up with the shaft-length so close to perfectly, that ya -(the viewer) can thus-then actually see all the way through the center-hole of the shaft ! _ Good-job !

Lol. I took about fifteen to get that. Couldn't get the camera to focus where I wanted.
I had a light shining on the wall behind, got the focus, held the shutter button half way to hold the focus and then looked for the light shining down the center. Held my breath and click.

Digitalis are great. Now I can delete the other fourteen

David

[DewCatTea-Bob]

" Couldn't get the camera to focus where I wanted. "

____ If anybody-else cares to try taking pix of their camshaft, ya might be temped to place your camera as close as possible to the shaft (so as to not waste any of the camera's pixel-total on side-ground), but the trouble with doing so is that the closest & furthest parts of the shaft will then be more difficult for the camera to keep all in focus.
So rather, it's best to place the camera at a distance that's at least 5-times (maybe up to 10 or 20 times, depending on the camera's max.MP) the length of the shaft, away from the tip-end of the shaft,, that way, the tip of the shaft & both lobes will all appear to be more equally focused.
(I wonder about how far David had placed his camera away-from the shaft !?)
While such separation-distance may seem unnecessarily distant,, with modern cameras which have over 4MP resolution, it really doesn't matter for this purpose (so long as the camera is set at maximum available detail-resolution).
__ I hope other members will now also provide pictures of their camshafts (like David has done).


Hopeful-Cheers
-Bob

[kaysystems]

I was using a 10mp point and shoot. I put it on full zoom and was about 18 inches away, maybe a bit more. The cam was then still quite small, so I just cropped the picture

David

[DewCatTea-Bob]

" I was using a 10mp point and shoot. "

____ I-myself don't know much about digital-cams, but I've heard that 80MP is the current state-of-the-art. _ However I now suspect that as low as 2MP would be sufficient for this cam-shooting task, (if spaced under 2-feet apart).


" was about 18 inches away, "

____ Then since your shot turned-out so well (spaced-apart by only 3 to 4 shaft-lengths),, I guess I was fairly-well off, to have suggested a space-separation of as much as 10 shaft-lengths, (since your pic.shot doesn't seem to display any focus-inconsistency between the intake-lobe & the shaft-tip).


____ So how many camshafts do you actually have besides that racing-cam, David ? ...
You've already mentioned 'Green&White', and 'Gray' cam.models,, and I gather that you must also have had a Monza and a w-c.250Mark-3 cam.models, as well... is that correct ?


Duke-Cheers,
-Bob