1968 250 MK3D rebuild - ex W/C Oil Pump

[DewCatTea-Bob]

By: machten...
" How many of the 73 black case greem frames actually had the Imola race cams is a matter of debate. From memory there was circa 15 bikes all up and they were not generally available to anyone "off the street" at that time. It's not unreasonable to expect that they were directed at guys that were going to race production 750 and so came with the original 750 1972 imola cams on some such bikes. "

____ I also recall reading somewhere back at the time that there were to be up to around 20 (un-street worthy, & likely unfinished/non black-cased) racing-only examples of the 750SS made available only to a selected-few approved by Ducati. _ But any specific details about those limited few concerning such things as camshafts, was then not known of,, so I never learned any specs of info about their employed D.cams. _ But I'd expect that at the time, if they didn't employ the very-same D.cams as the two 750s which had won Imola, then they were likely fitted with a prototype of the D.cam-model which later received the title/name "Imola cam".
__ But any camshafts such as those, made for such racing-only Ducati-models, would be more akin to the 'Racing' (rather than the 'Special') DESMO-camshafts made for the 350F1D-racers, rather than streetable versions like the R&W-D.cam !


" The 74 Greenframe was available to anyone
The 74 greenframes don't even start to come onto the cam before north of 4000 rpm
They are definitely more aggressive than Sports and GT's which are actually quite tame, by comparison. "

____ That I KNOW, as I had ordered a 750SS when they were all 'black-cased' but, by the time I received a 750SS in early '74, it was the non black-case version,, and I was so disappointed about that missing detail, that I didn't keep it. _ But did have it long enough to have taken note of it's wonderful power ! _ What a supremely pleasurable thrill it always provided !


" and did have the option of a the standard cam and so called "imola" cam.
I doubt that was the same cam as the 72 or 73 short stroke race bikes (as you mention). "

____ I had not meant to mention anything at all about the later 'short-stroke' (86x64.5mm) versions of the 750-racers ! _ Just the 750s which had taken 1st & 2nd place at Imola.
__ I don't recall it being an 'option' to order any streetable version of the 750SS with it's std.750SS-D.cams substituted with the 'Imola'-cams. _ But that does seem like it would've been a genuine option for any non-street-worthy version of the 750SS, (if available at the time).


" the 250 MK3D is now reassembled and ignition timed ready for a "fire up" in the morning with Marco's stock cam. "

____ I wasn't expecting that you'd have the opportunity to test-out any other B&W-D.cam other than your own... _ So I gather that the B&W which you're now testing is the D.cam which was even less perfect than your own 5-hole version ? _ If so, it seems a smart-move for your friend to allow you to fully check-it-out for him, and you both get additional learning-experience.
__ Seems fairly disappointing though, that you didn't let us know how all the related shim-adjusting work finally went for you, (so as to get that particular D.cam adequately set-up within your 250D.head) ! _ Did you get additional -(besides that which you only had before), shims (or valves or spring-ties) for getting that particularly imperfect D.cam all set with your refaced-rockers, or just how did you get past your previous set up troubles ?
And if you finally managed to obtain your desired .0015" closing-clearance, what did that clearance set-up actually turn-out to provide at TDC, (with this D.cam you're trying-out) ?
__ Anyhow, after you've learned all you can with that stock-type D.cam, please don't forget to let us know how things are going for you when you install & set up your VeeTwo-D.cam !


Hopeful-Cheers,
-Bob

[machten]

____ I wasn't expecting that you'd have the opportunity to test-out any other B&W-D.cam other than your own... _ So I gather that the B&W which you're now testing is the D.cam which was even less perfect than your own 5-hole version ? _ If so, it seems a smart-move for your friend to allow you to fully check-it-out for him, and you both get additional learning-experience.
__ Seems fairly disappointing though, that you didn't let us know how all the related shim-adjusting work finally went for you, (so as to get that particular D.cam adequately set-up within your 250D.head) ! _ Did you get additional -(besides that which you only had before), shims (or valves or spring-ties) for getting that particularly imperfect D.cam all set with your refaced-rockers, or just how did you get past your previous set up troubles ?
And if you finally managed to obtain your desired .0015" closing-clearance, what did that clearance set-up actually turn-out to provide at TDC, (with this D.cam you're trying-out) ?
__ Anyhow, after you've learned all you can with that stock-type D.cam, please don't forget to let us know how things are going for you when you install & set up your VeeTwo-D.cam !

Bob, It's OK, relax. I've got spreadsheets of info on that for a number of the cams and will write something up soon, but i had to fly out to the other side of Aus for work on Monday and am there now for the working week, so needed to get to get on with doing the job rather than blogging it. Expect to see some data and conclusions next weekend.

Kev

[machten]

Quick update: Nice quiet running in the top end with the rebuilt rockers and stock cam and new clearance settings. Testing has started, but I have some ignition timing issues with roll on above 100 km/h. Need to do a bit more playing around with ignition timing and some strobe work before i report back

Kev

[DewCatTea-Bob]

" Nice quiet running in the top end with the rebuilt rockers and stock cam and new clearance settings. "

____ When you state "stock cam", I assume you mean a B&W-D.cam for sure but, I can't be sure whether you mean your 'original' or other. _ As it's fairly interesting to know if you're proving that the old/used 'shelved' / questionable B&W is working so finely. _ (If so, then you're testing-out two changes both at once... that old/questionable D.cam AND your refaced-rockers, together.)


" but I have some ignition timing issues with roll on above 100 km/h. Need to do a bit more playing around with ignition timing and some strobe work before i report back "

____ I assume that you've already ruled-out the spark-plug's entire spark-juice circuit (including the plug itself of course) !?
__ Also, If you were pretty-sure that you already had the ign.timing set well, then I'd suggest trying another carb (looking for identical roll-on behavior) before spending time on the ign.timing again.


Hopeful-Cheers,
-Bob

[machten]

From wcorey..

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...

This is the last one I know of Bill, but I haven't yet tested mine, and presumably theres a few more out there, but I sure as hell couldn't find them. This is the one that was left from the guy I biught mine from. Worth watching, anyway. This is their Road/Race cam that I have.

http://cgi.ebay.com.au/Ducati-single-250-350-450-Desmo-Vtwo-cam-NOS-/270732172514?pt=AU_Motorcycle_Parts_Accessories&hash=item3f08e51ce2


You might want to check his other parts for sale on eBay. A nice selection. I was fortunate enough to be offered the opportunity to troll through them in person before he put them on eBay!

Kev

[wcorey]

Worth watching, anyway. This is their Road/Race cam that I have.

Thanks for the heads up, will certainly be keeping an eye on it, he does have some other nice bits there as well. The budget for toys is a bit stretched right now but this would be worth selling something off for, seeing how difficult they are to come by. I mailed him about the shipping, came out to the same amount as the complete wheel he's also selling, AU $88, seems like either the wheel would be a lot more or the cam a lot less...

While I'm eager to hear the results of your testing, probably won't be very applicable to my D450 application. After reading Bob's assessment of the D450 being relatively under-cam'ed compared to the D250, it seems safe to assume that while it may be bordering on the extreme side for the D250, it would be a good improvement on the D450 even for street use.


Bill

[machten]

I mailed him about the shipping, came out to the same amount as the complete wheel he's also selling, AU $88, seems like either the wheel would be a lot more or the cam a lot less...

Depends how you send them. For a cam to the US (not sure if that's where you are) I'd have thought you can use airmail for less than US$20, or Registered Post International for circa US$23.I thought he said in his auctions shipping at cost or something like that.

Australia post international calculator is here... http://auspost.com.au/apps/international-parcel.html

Kev

[DewCatTea-Bob]

By: wcorey...
" While I'm eager to hear the results of your testing, probably won't be very applicable to my D450 application. "

____ That's correct, as the results in a 450 are quite different from that in a 250, due to the fact that the 250's smaller cylinder is much easier filled !
__ Also of concern, Kev states that he got the "Road/Race" version of the V2.desmo-cam, while the one left-over for sale is listed as the 'Sport/Race' version. _ And going by the given names, I now suspect that Kev has gone & done that which most power-greedy types are inclined to do, and went-for the hottest of the two d.cams which he had a choice of. _ Which no-doubt would've been the best option IF his chosen d.cam was intended for a 450. _ But now that it seems that there was a milder V2.cam to pick from, I'm thinking that Kev made the wrong choice for his 250.


" After reading Bob's assessment of the D450 being relatively under-cam'ed compared to the D250, it seems safe to assume that while it may be bordering on the extreme side for the D250, it would be a good improvement on the D450 even for street use. "

____ It's probably clear enough what you are actually meaning to say Bill, but to clarify for others, I'm adding the following.....
__ The stock-production 450-DESMOs (all with the 250 Blue&White-D.cam), are by no means under-cam'ed, (as I've claimed the stock 450-SCR.models are!) ! _ In fact, even the stock 450D.engine is OVER-cam'ed, when still matched-up with the stock muffler !
However, with a better suited exhaust-system, the 450D.models are indeed running with a less than optimum D.cam !
__ On the other hand for "street use" (which really ought to include a reasonable muffler), an even wilder cam than the B&W is certainly not going to provide any useful improvement, and in fact would most likely reduce overall-power -(throughout the entire rev-range) !
So these desires for hotter cams should be kept-in-check with consideration of whether for 'street-use' OR (possibly illegal) 'road racing' !


Dukaddy-DUKEs,
-Bob

[machten]

__ Also of concern, Kev states that he got the "Road/Race" version of the V2.desmo-cam, while the one left-over for sale is listed as the 'Sport/Race' version. _ And going by the given names, I now suspect that Kev has gone & done that which most power-greedy types are inclined to do, and went-for the hottest of the two d.cams which he had a choice of. _ Which no-doubt would've been the best option IF his chosen d.cam was intended for a 450. _ But now that it seems that there was a milder V2.cam to pick from, I'm thinking that Kev made the wrong choice for his 250.

Nope. That cam and mine are identical. Same part number (V2-03-001), just described differently. I had the choice of either, but agreed to take the one out of the packet as it might be easier for him to sell the one still in the packet later. VeeTwo cams are stamped with the part number (shame Ducati didn't do the same!) and I know the seller, so I knew what I was getting.

Kev

[DewCatTea-Bob]

" That cam and mine are identical. Same part number (V2-03-001), just described differently. "

____ Thanks for clearing-up my bad thinking (even though I had hoped I was correct about there being two separate versions) ! _ Originally I had (correctly) assumed that both new VeeTwo-cams were the same model/version...
I guess I jumped to (new)- conclusion, because the description of the one now listed stated the VeeTwo-name of it is "Sport and race", and then I noted that Kev mentioned that HE had the "Road/Race" version, as if to make a point that HIS cam was not the same as the one listed, due to his seemingly otherwise unnecessarily added sentence: "This is their Road/Race cam that I have.", which didn't seem to make as much sense to bother stating unless confirming that the name of the cam he had obtained is indeed not the same as the other cam that's still available.
NOW, I realize that what Kev had actually meant by "This", is the cam found at the end of the link which he had included, (thus ACTUALLY intending to indicate that that other V2.cam is the same as his own).
__ Sorry for my mistake, but it did lead to some thoughts of interest (even if incorrect).
____ So now we're still left wondering which name, ("Sport" or "Road"), is the real/official-name for these particular VeeTwo-d.cams !?


Sorry-Cheers,
-Bob