VHB 29 setting for scrambler 350/73

[Roland]

Today's work:

checked plug gap: is 0.6, nothing changed.
installed carb again.
added cable frame to motor (probably useless, but who knows).
changed starting procedure, now applying small amount of throttle.
used another, shorter spring on idle screw, can be screwed in one turn more before going on block.
Now kicking with some small throttle opening, it starts good and idles without using choke. 30° here.

Idle screw is full in with spring on block!

Trying to drive, it will cough, small choke opening helps and it has power and pulls on.

Now to do:

mixture must be enriched. Will lift needle one or more positions.
Slide with 50 cutaway is installed. I have a slide here with 40. How does this affect mixture?

Tomorrow to be continued.

Thanks for assistance!

[Roland]

found in DellOrto-manual;
smaller cutaway will enrich mixture.

Tomorrow i will change slide from 50 to 40, and lift needle position.

This should be the correct tendence.

[Jordan]

Because of the non-choke type of enrichening device on the carburettor, it might be better to not open the throttle when starting, until it has started.

[Roland]

a short time later...

This is my setup.
Is this the 450 type airfilter?

[Jordan]

> Is this the 450 type airfilter?

Not necessarily, because the same air filter was fitted to other engine capacities I think.
The info provided in the Ducati spare parts list (stating different slide cutaways depending on whether it is a 450 or not) seems confusing or incomplete. What indeed is a 450 air filter?

Dell'Orto describe the amount of cutaway in tenths of a millimeter.
A throttle slide stamped with 40 has the intake side of it 4mm higher than the back, 50 means 5mm, etc.
Cutaway has most effect between 1/8 and 1/4 of throttle opening.

A parts list is here:
https://www.rpw.it/Files/Ducati_Monocil ... _5m_CR.pdf

Some pages from it:
download/file.php?mode=view&id=8000
download/file.php?mode=view&id=8001
download/file.php?mode=view&id=8002
download/file.php?mode=view&id=8003
download/file.php?mode=view&id=8004

[Jordan]

Just to mention, I once used the large SCR air filter on my 350 with VHB, but I had carburettor problems with that.
I don't remember why, but that I thought the corrugated rubber connecting hose might have caused it.
When I stopped using that filter and hose, the problem went away.
Maybe it's worth an experiment - to try it without the hose?

[graeme]

I agree with Jodan re the connecting hose.
Try it without the hose

Graeme

[Roland]

Thanks Jordan and Graeme.

The long rubber joint looks strange, indeed.

I have a KN-filter cone here and will install it, rechecking all settings, Slides 40 and 50 are available.
Will happen next week, at first i need to tune the front brake, but this is topic for another thread.

so long!