Hot Starting on my 350 MK III

[machten]

Hi Bob,

I have enough "mass" to do it (note I didn't say height!)! I've never tried to use that method though, as it seems a lot more effort and as the knees aren't what they used to be, I'm all for effective minimalism when it comes to kick starting.

With the White camshaft and using a conventional procedure my 450 will start first kick 90% of the time. If it didn't start by the second then I'm checking if I've done something stupid like left my kill switch on (I have an Electrex CDI ignition and charging system installed). I'm in the process of working out a new starting routine since I installed a green and white camshaft. I suspect the much higher camshaft overlap requires a few more priming cycles to get sufficient fuel in the chamber for a good starting mixture. Previously, two induction cycles with the enricher on did the job, now it seems I need 4-6, but I'm still experimenting.

I do have a friend who has a 350 springer with the green and white camshaft who I have seen starting using a series of fast continuous kicks (where he seems to start the next kick before it has stopped spinning from the current kick) without even using the decomp lever, but he's about 6' 4" and his knees must be in better shape than mine!

Kev

[graeme]

Hello Kev,
Does the green white cam make much difference to a 450?
Is that the only change from standard?

Graeme

[Bevel bob]

I have learnt that there are more than 1 type of Green/white with very different timings so you need to be more specific. Also the effect of these timings are quite different depending on the motors capacity.Look at previous posts.

[machten]

Hi Graeme,

The short answer is, I can't be absolutely sure what improvement it contributes on its own based purely on my own experience. I was rushing against the clock to get the 450 together for the Albany Hill Climb including an engine strip and rebuild as I needed to get the little end re-sleeved and I knowingly committed the cardinal sin of a doing a few things at the same time.

The two things I did at the same time that make it hard to be sure were changing the camshaft and installing a Conti style exhaust pipe. The combination of the two definitely contributes more power from mid range upwards. Previously, the white camshaft and stock silentium exhaust ran out of puff (and topped out the revs) much earlier. I'd estimate the new set up provides access to nearly another 1000 RPM. Interestingly, I think I've lost next to nothing down low. I also needed to play around with the VHB jetting just a little bit to better suit the new arrangement.

One thing I have tried as an experiment was to put the Silentium back on with the G&W camshaft. Forget it. It won't run over 4000 RPM. You have to run with the megaphone style pipe. I wouldn't be at all surprised if the exhaust pipe change contributed as much or even more to the performance improvement as the camshaft change did.

I'm curious myself, so when I have some time (ie. when I've sorted out a few "must do" things on my other mechanical mistresses from Bolonga) I'm going to put the White camshaft back in and test exactly what you are asking.

I've never figured out why Ducati went to the trouble of producing and installing a G&W camshaft for the 350, but used the 250 Scrambler White camshaft in a 450. It defies logic to me. I know when Lex and I were in Europe during our occasional "jousts", he on his '69 350 with a Silentium cigar type exhaust and me on the 450 with the stock Silentium pipe, I'd easily get to about 55mph in front of him, but after that, he was going past me.

Here's the 450 in Hill Climb config with the Conti style pipe from Road & Race...



I don't know exactly what RPM I was getting up to on the climbs as we have to have our speedo and tacho covered (it's a time trial, not a race...yeah, right!), but it sure is much more free up top.



Kev

[graeme]

Ta Kev,
That explains a lot for now.
Thanks for the pictures.
I have a yellow 74, an RT and a dunga 450 '74 scrambler. (dunga as in not restored and very ugly but it goes)
The difference between the three bikes is an extra step in power for each engine. (the yellow engine has been made to breath and is by far the best)
I have a Grey (Gray) cam that I'll try in the scrambler and I can swap the pipe (conti type) from the yellow bike.
So just wondering what your feeling was with your 450.

Regards
Graeme

[machten]

I'd be interested to hear your thoughts on the effect of just trying the megaphone and maybe richening up the fuel a bit on the scrambler, Graeme. I find the 450's fairly lazy rev'ers anyway (in comparison to my 250, anyway).

The other thing to bear in mind I guess (regarding my lack of understanding re the White in a 250 and 450 and a Green & White in the 350) is that the Desmo singles used the same Blue & White camshaft through the range 230 - 450 as far as I know.

As Bevel Bob points out, there are at least 2 different Green & White camshafts that I'm aware of. The one I have in my 450 is a reproduction of one of them. I have the specs somewhere.

Lex's 350 experienced a reasonably distinct lack of power down low and riding along side it, even I could hear it start to come on at certain revs. Not the same distinctness, but a little like a slow two stroke power band. Even more noticeable at high altitude. I don't experience that on the 450, so it may be a different spec, or....

Other's in this place will be able to offer far better insights than me, I'm sure! In any case, please let us all know the results if you do the pipe change.

Kev

[machten]

My own words...

I'm in the process of working out a new starting routine since I installed a green and white camshaft. I suspect the much higher camshaft overlap requires a few more priming cycles to get sufficient fuel in the chamber for a good starting mixture. Previously, two induction cycles with the enricher on did the job, now it seems I need 4-6, but I'm still experimenting.

Does anyone have some thoughts about using a larger enricher jet for starting with the Green & White camshaft? I've got a few spare and could use a jet drill to enlarge one as a test. Just something I've been thinking about....

Kev

[DewCatTea-Bob]

____ WHOA!!!
WHOLELY-SMOKES ! ... In recent months I've become fairly used-to a lack of new/response-posts soon following-up new-posts, (at-least within the threads which I've been contributing my-own posts to),, so I figured I'd wait & let this thread drop-down a space or two from the top (of the main forum-page) before then-next posting my response-post to Kev's post. _ And now here I come to place my intended post and rather discover that there's been a much unexpected explosion of new posts in the meantime ! _ Within which, they contain a fair-number of various topic statements that I want to respond-to
in most everyone of them, too !
__ However, starting with Graeme's somewhat slightly off-topic question (that rather concerns 450-performance),, this thread seems to have become the closest-thing to being 'highjacked' that I've ever considered any thread as having to've so become.
I've actually been long looking-forward to such a discussion continuing-on forthward, but-rather from one of Kev's other two preexisting threads concerning all this particular (off-topic here) newly developed subject-mater ! _ So I sure don't wish to curtail any of this (somewhat vaguely related) 450-stuff that Graeme has inspired here ! _ Yet I-myself think it should all be moved-over to one of Kev's past threads that's considerably more-directly related to all this newly developed 450-performance subject-mater.
There's two ways to do-so,, I could possibly completely move all the related posts over-to Kev's most recent thread on the very-same topic/subject-mater, or, rather virtually-copy them over-there, (which I'm most inclined to do !). _ So if no-one can think-of any downside of doing so, then I'll soon get started with such. _ But it will take a fair while, so I hope there will be sufficient patients with continuing-on with the stuff having to-do with Kev's 450-related topics.
__ I'm most interested in first continuing-forth with the post-topics that Graeme has inspired here,, so the things that I had meant-to respond-to within Kev's post (seen copied below), will now rather be put on the back-burner for the time being.
__ Anyone wishing to comment anything about this-concern, is encouraged to do-so ASAP,, as I expect to get-going forthward as intended within 2-hours.
Bar any timely (acceptable)- objections, look for Kev's older related thread to soon pop-up at the top of the active list of threads on the main forum-page.

Dct.B

Hi Bob,

I have enough "mass" to do it (note I didn't say height!)! I've never tried to use that method though, as it seems a lot more effort and as the knees aren't what they used to be, I'm all for effective minimalism when it comes to kick starting.

With the White camshaft and using a conventional procedure my 450 will start first kick 90% of the time. If it didn't start by the second then I'm checking if I've done something stupid like left my kill switch on (I have an Electrex CDI ignition and charging system installed). I'm in the process of working out a new starting routine since I installed a green and white camshaft. I suspect the much higher camshaft overlap requires a few more priming cycles to get sufficient fuel in the chamber for a good starting mixture. Previously, two induction cycles with the enricher on did the job, now it seems I need 4-6, but I'm still experimenting.

I do have a friend who has a 350 springer with the green and white camshaft who I have seen starting using a series of fast continuous kicks (where he seems to start the next kick before it has stopped spinning from the current kick) without even using the decomp lever, but he's about 6' 4" and his knees must be in better shape than mine!

Kev