1968 250 MK3D rebuild - ex W/C Oil Pump

[machten]

____ "Street - Race " , for which size engine ? _ Cuz that which is wild in a small cylinder becomes rather mild in a much larger cylinder !

That's the description they use. See the photo of the specs sheet in my last post. I have to admit it looks a bit more radical than I was expecting, but it has piqued my interest now that I have it. It's no big deal to try it out, so I'll give it go and see what happens.

__ Now it will be interesting to see if another desmo.cam maker can make them any better than Ducati did, so hopefully you will take the extra time to PURPOSELY shim for checking for any possible conflict-binding, (just to see how it compares to any other Ducati-made D.cams you've checked).
__ That is, IF that wilder d.cam will fit into your (stock) D.head...
I've asked you about this possible fitment-issue before, as I've heard that SOME of the V2-d.cams will not fit into a stock-sized cam-tunnel !
and....
Downside is a bit more thrashing of your valve train and also that I believe you need to modify the head to install these (?).

I haven't done a final shim up yet, but it certainly fits in the tunnel fine and rotates without any issue or contact with anything it shouldn't when loosely shimmed. And don't worry, I know how to find a bind area now in my sleep - and I'll be looking for that. What head mods are you thinking are required (as it seems to just slot right in there)? Maybe I'm missing something?

the 29mm carb will choke-off what the extra-wild cam is capable of delivering at those high RPMs, (so a 32mm carb & matching in.port will be of more use, up-there!).

Yes, this may well be an issue. Or the cam may just make the 250 intractible for street use - but what the hell - it's worth finding out.

"Another thing of note is that this VeeTwo camshaft is 1oz lighter than the stock W/B. "
____ Could you tell us what percentage less that is, or just give us the actual weight of each ?

Stock W/B = 11.3 oz = 321g
V2 = 10.3 oz = 293g

I mentioned this only because I noticed it when handling them both. I guess when racing, every oz helps.

I'd like to know how you came-up with those stated figures and how you know that they are fair to directly compare

I'm assuming Bill determined the V2 ones from the spec sheet I attached.

__ It's too bad that you don't have two DESMO-250s, so that you could then be able to confirm that my expectations are pretty-much the actual case !

Yes, unfortunately not the case ! And I don't have ready access to a dyno either, so I'm going to do the next best thing. I'm planning to fit the stock W/B and myself and four other duc single owners will have a ride on it an make some notes, then we'll change it to the V2 camshaft and all have a ride and make comparisons over a barbeque and a beer or two. If it doesn't work for the 250, we have yellow 450 desmo amongst this group it may work for. Seems like a good way to spend a sunny autumn day, anyway.

Kev

[DewCatTea-Bob]

" That's the description they use. "

I would think that 'Street - Race' would refer to a cam that's a racing-cam that's not too wild to be also streetable. _ And that's no-doubt the actual case if used in a 450, and probably even in a 350, but the B&W-cam is already considered to be a streetable race-cam for the 250,, so anything much wilder shouldn't be very 'streetable' for the 250.


" See the photo of the specs sheet in my last post. "

____ That pic is way too dark for me to see, and I haven't yet gotten-around to adjusting it so that it's light enough for me to see.


" I have to admit it looks a bit more radical than I was expecting,
It's no big deal to try it out, so I'll give it go and see what happens. "

____ Since you're so well used to doing the work and actually like doing the valve-adjusting job,, it would be quite a disappointment if you weren't so inclined, as you're not the only one who really wants to learn of the results !


" but it certainly fits in the tunnel fine and rotates without any issue
What head mods are you thinking are required (as it seems to just slot right in there)? Maybe I'm missing something? "

____ I guess you are...
While you've been supplying quite useful as well as not so useful measurement-figures of all your well measured D.cams, an omitted measurement-figure that's of importance for any non-standard/B&W D.cam, is the overall-size of the 'D-shape' -(of the closing-lobes)! _ Cuz when that 'D' gets too large, it then can't fit into/through the stock cam-tunnel (even when the shaft-center is not properly-aligned) !
___ So in such case, there's two different methods for cam-tunnel head-modification, (of which I'll tell about after I get around to posting all the measurements of my own factory-made 350 & 450 D.cams).
That your V2-D.cam slid right-in without any interference with the tunnel-opening, (thus your largest 'D' must be smaller than the tunnel's diameter!), leads me to think that that cam-model got it's 'Street' name partly due to the likely-hood that it could employ the most lift possible without need for any cam-tunnel head-modification.


" Yes, this may well be an issue. "

____ Well now I wouldn't exactly refer to the absence of a modified intake-tract as "an issue" !
I'm sure that the high-range of the power-band will still be improved somewhat, but just not as much as the wilder cam is capable of allowing, (over the stock-cam). _ In other words,, while a larger intake-tract would certainly benefit the high-RPM power with either cam, a larger percentage of the wilder cam's high-RPM efficiency would be ignored, (compared with that of the stock-cam), with the intake-tract left stock-sized.


" Or the cam may just make the 250 intractible for street use "

____ I doubt that any cam with it's given title/name would cause the engine to not run/produce well enough below 4000-RPM to possibly then become "intractable" for normal take-offs from stops at street-corners.
It's just possibly going to make it act/feel more like a 200 than a 250, when at lower RPM. - (Unless Bill is right that it's valve-timing is ACTUALLY milder !).


" but what the hell - it's worth finding out. "

____ INDEED !!


" Stock W/B = 11.3 oz = 321g
V2 = 10.3 oz = 293g "

____ So that makes the V2-d.cam almost 9% lighter ! _ No BIG-deal there of course, but does indeed contribute slightly to quicker revving.
__ Have you also compared your 5-hole D.cam with any of the 4-hole versions? - (Just a related detail of slight interest.)


" I'm assuming Bill determined the V2 ones from the spec sheet I attached. "

____ Still, the main concern remains... Depending on what method was used to determine that cam's actual valve-timing, it just might have still wilder duration (than the B&W) !


" And I don't have ready access to a dyno either, "

____ My-own best substitute for dyno-testing is to run against another Duke with an equal sized rider (or another bike & rider combo that's previously proven to have been a fair match) ! _ While that before & after comparison-method doesn't produce any data-figures, it does provide real-world outcome ! _ And thus of course the most desired actual bottom-line results.


" I'm planning to fit the stock W/B and myself and four other duc single owners will have a ride on it an make some notes, then we'll change it to the V2 camshaft and all have a ride and make comparisons "

____ That's just fine as well, especially if done along-with that which I've suggested. _ Otherwise, show me four guys (who each had taken a test-ride alone), with a few fresh beers under their belts,, and I'll then (separately) show you four guys with differing opinions.
__ Besides comparing seat-of-the-pants power/acceleration, and directly comparing against another bike/rider during full-on acceleration through the gears,, another fairly important aspect to compare is: 'low-speed high-gear full-throttle roll-ons' ,
as well as within mid-range Rs, also.
As performing those comparisons can show what's lost in exchange for that which has been gained ! - (As it's quite possible to lose considerably more at lower revs than what's gained at top-revs, and end-up with less overall/average power [over the ENTIRE rev-range, with too wild of cam-timing]).


" If it doesn't work for the 250, we have yellow 450 desmo amongst this group it may work for. "

____ So then there's possible additional reason to prefer to test-out the V2-d.cam first.


Fun-Cheers,
-Bob

[machten]

I'm just about to clear the bench for doing some work on some shimming setups, so in the interests of getting the scales out of the way, I'll just answer this one now and come back to the rest later..

____ So that makes the V2-d.cam almost 9% lighter ! _ No BIG-deal there of course, but does indeed contribute slightly to quicker revving.
__ Have you also compared your 5-hole D.cam with any of the 4-hole versions? - (Just a related detail of slight interest.)

Stock W/B = 11.3 oz = 321g
V2 = 10.3 oz = 293g
Kev's 5 hole cam = 11.4 oz = 326 g

Kev

[DewCatTea-Bob]

"Stock W/B = 11.3 oz = 321g
Kev's 5 hole cam = 11.4 oz = 326 g "

____ So comparing the weight of the 4 & 5 hole Blue&White D.cams, you've found that the 5-hole version is actually 5-grams HEAVIER than the 4-hole version !?
So what gives? ... If this relationship is not in error, then are the sets of holes not exactly the very same size, (being fairly larger in the 4-hole version) ? _ Or could it be that the oil-passage hole through the center of the shaft is a bit larger, within the 4-hole version ?


Curious-Cheers,
-Bob

[machten]

So comparing the weight of the 4 & 5 hole Blue&White D.cams, you've found that the 5-hole version is actually 5-grams HEAVIER than the 4-hole version !?
So what gives? If this relationship is not in error, then are the sets of holes not exactly the very same size, (being fairly larger in the 4-hole version) ? _ Or could it be that the oil-passage hole through the center of the shaft is a bit larger, within the 4-hole version ?

The cam closer lobe holes are all the same size. In the W/B cam weighing 321 (Marco's cam), the centre oil passage goes almost through to the thread where it is plugged with just a small pinhole at the end. Additionaly, this cam's oilway is slightly larger diameter, and will accept a 13/64 drill bit, the other will not.

In my cam, the oil way stops completely just past the exhaust closer lobe.

The lightly used R & R cam weighs in at 326 and the oilway is the same as mine.

The Mario Sassi cam weighs in at 312 and the oil way runs right through the cam unplugged.

More variations!

The VeeTwo oilway also on runs through to just past the exhaust closer lobe and stops.

Kev

[wcorey]

I'd like to know how you came-up with those stated duration-figures and how you know that they are fair to directly compare with Ducati's, (since many such stated-figures are not taken at the very-same lift-points as Ducati has done them !).

For the duration numbers I just did the math from the timing specs. Of course you're correct in that I don't know what clearance was used in the stock specs I used but for purposes of comparison in this particular case I figured it would be too small to matter. The V2's are measured at .5mm and even if the stock ducati specs are taken .5 different one direction or the other, it moves the timing figures over some but would cause very little change in the amount of duration (I think). There's the good reason in using lobe centers for timing, doesn't matter from what lift the timing numbers were arrived at.

The source I used for the stock B&W timing spec's was Jim Pianetta's cam data sheet, of which some are supposed to be from owners manuals and others are actual measurements. There are 4 or five B&W's listed and all but one (from '68 250 manual) are consistent. I also have the same numbers down in a file full of misc 450 specs I've compiled over the years but don't recall the source. The 450 manual on this site has the specs too but have two degrees transposed (80/82 vs 82/80 from the other source) between intake close and exhaust open.

but it certainly fits in the tunnel fine and rotates without any issue or contact with anything

So it fits right in, that's great... I had read somewhere that these required modification, which is one reason I never went out of my way obtaining one. Now I'll have to start looking...

Going back to the late '90's I was going to get a set of V2 cams for my belty 900ss, the currency exchange rates made them quite a deal then and I figured I'd get the singles d cam while I was at it, just for possible future use. I ended up getting a 996 and slowly lost interest in the 900, so the 2 valve cams never happened. I did end up putting sps cams into the 996, which have a fairly high lift with very minimal duration/overlap. Quite a transformation, brought pretty much the entire power band up with a nice big lump of torque in the middle. One thing nice about the 4 valver's is the separate int/ex cams allow the ability to move cam timing around to alter where on the curve the highest power gain happens. I don't believe that's possible with the two valver's because the intake needs to go one way and the exhaust the other.

Bill

[Pete]

I am not sure if this fits with this discussion, but I came across this site that has B & W and NCR cams for sale as well as other Ducati single parts.
http://www.loudbikestore.com/bevel-drive-c-1104_1134_1144_1186.html?zenid=ba9e35ec25a3739187548a3d5de7fd0d

Pete

[machten]

One thing nice about the 4 valver's is the separate int/ex cams allow the ability to move cam timing around to alter where on the curve the highest power gain happens. I don't believe that's possible with the two valver's because the intake needs to go one way and the exhaust the other.

Now that would be handy! Myself and the and Imola rider pictured earlier in this thread recently dial gauged his 73 Sport that he just got back on the road on Sunday after a restore. Ducati quotes the twins cam timing at +/- 5 degrees accuracy (per camshaft). His Sport had never really had the crisp bark it should. We found the the cam timing was the worst possible spread - plus 6 on one pot, -5 on the other. (So this isn't my first play into Ducati camshaft "inaccuracies"!) We used some offset woodruff keys to fix it and it now sounds and reacts as it should - but you are right, the best you can do even with the offsets is find the best compromise for inlet/exhaust as the relationship is fixed by the lobe centre angles.

So it fits right in, that's great... I had read somewhere that these required modification, which is one reason I never went out of my way obtaining one. Now I'll have to start looking...

Not easy to find, Bill, based on my experiences. I even checked with Brook Henry too see if any were left in the old VeeTwo stock, but no. The guy I bought mine off had one more, still in the packet, but I think Marco's going to snaffle that one for his 450. I'll see Marco tonight at our regular Ducati spannering night (my kids call this our "bro-mance" - my wife calls it our Ducati knitting circle!). If he's not intending to I'll let you know, as that one will be up for grabs.

but I came across this site that has B & W and NCR cams for sale as well as other Ducati single parts.

Yes, I saw those on loudbike. They have some nice stuff there from the Romanelli parts stock. I've spoken to the owner Steve Munro before. He's a nice fella and I bought some Dellorto V13 needles from them as I couldn't seem to get hold of those anywhere and they arrived much pronto. You can also buy a cam new a bit cheaper from Amici Della Scrambler http://www.ducatiscrambler.com/2006/ricambimotore.htm , but I'm not sure if it is an original ducati cam (and they call it a "White" cam). I was lucky enough to pick up my brand new VeeTwo cam for AU$250, so if it works out, it's a bargain.

Kev

[DewCatTea-Bob]

By: matchten...
" In my cam, the oil way stops completely just past the exhaust closer lobe. "

____ So then it seems that the extra weight at the right-end of the shaft is what's mostly responsible for the camshaft weighing 5g more, despite it's closing-lobes including the two additional holes.


" The lightly used R & R cam weighs in at 326 and the oilway is the same as mine. "

____ So it weighs same as your 5-hole version but, I thought yours was the only D.cam with 10 (rather than 8) total holes !? _ If it indeed is only a '4-hole version', then I gather that it's oil-inlet passage-hole must likely be somewhat larger than that in your 5-hole version !?


" The Mario Sassi cam weighs in at 312 and the oil way runs right through the cam unplugged. "

____ So assuming that it's also another 4-hole version, and it's oil-inlet passage-hole is the same diameter as that in yours,, then it seems that the weight of the extra steel within the right-end of the shaft of your D.cam, is well*over the 14-grams difference (* since yours has the 2 extra c.lobe-holes).


" More variations! "

____ It's too bad that the production-dates weren't stamped into each shaft, cuz we could then easily know for sure what the actual progression-order (of the design-differences) was.


" The VeeTwo oilway also on runs through to just past the exhaust closer lobe and stops. "

____ This seems to indicate that the D.shafts with the minimum-length oil-inlet passage-holes, are of the most recent B&W-D.cam design.


Curious-Cheers,
-Bob

[DewCatTea-Bob]

" but I think Marco's going to snaffle that one for his 450. "

____ It would then be interesting to check that one as well, so as to determine whether that d.cam manufacturer has any better consistency than the B&W-D.cams you've checked !


" You can also buy a cam new a bit cheaper from Amici Della Scrambler,
but I'm not sure if it is an original ducati cam (and they call it a "White" cam). "

____ It makes fair sense that a place with "Scrambler" in their name would sell the 'White' cam -(a springer-type camshaft), since 4 different scrambler-camshafts with that same color-code have been produced by Ducati !


Dukaddy-DUKEs,
-Bob