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setting the timing
Posted: Tue Aug 02, 2011 6:11 am
by Per Garbos
I have the original Electronic ignition system at my 250 Desmo and would try to set the timing with a stroboscope.
But i am not sure where to find the marks,
There are som at the clutch cover - a line and a dot but nothing at the crankshaft - at least as far as i can see.
Do i need some special tool or are there some other ways.
Per
Posted: Tue Aug 02, 2011 9:21 am
by bobnorton
Hi Per, You will need a pointer to fit to your crank end on the drive side ,i think the outer case is marked, Classic Ducati (Jones?) has pointers.These lock into the notch in the end of the crank after you take the plug out.I'm not familiar with desmos.
Posted: Tue Aug 02, 2011 12:24 pm
by Per Garbos
Thanks, just been looking at Classic Ducati webside and i will contact Jones tomorrow. The tool is not that expencive so i will go for that.
Best Regards Per
Posted: Wed Aug 03, 2011 12:52 am
by bobnorton
HI Per, I don't know what the advance range on you motor is but on my old 250 i just set the static timing to give me the most kickback i can stand and its still not advanced as much as the motor needs for max performance!! Crude yes but i actually want to ride and be able to restart on the road, I must be a bit odd as no one else rides the things regularly.
Posted: Wed Aug 03, 2011 8:58 am
by Per Garbos
Thats sounds heavy. - my 250 is heavy to kick over but i dont have the feeling that it will kick back.
Static is 5-8 degrees and advanced it is 36 -38 according to the manual.
Best regards Per
Posted: Thu Aug 04, 2011 1:00 am
by bobnorton
Hi Per, At any more than 5 degrees static starting becomes unreliable on my 250, I dont think my AAU gives the specified advance either, perhaps a couple of degrees less,so full advance is not really enough,I dont recommend kicking against the compression,bad for gears and stand. Best to ease past compression before kicking.Widecase has better gears and stand.My bike is faster with 10 degrees static but a pig to start and will stall too easily. Thats no good i need to ride!!.
Posted: Sat Aug 06, 2011 5:09 am
by Per Garbos
I agree about the kickstarter problem - even the widecase is stronger.
Problem with desmo is that a valvelifter is not an option.
But i think that some of the non desmo had valvelifter.
BR Per
Posted: Thu Sep 08, 2011 3:24 am
by maelstrom
Not exactly on topic however.
Static timing.
There is a dot on your ignition rotor and a corresponding mark on the stator.
Assuming you know how to use a degree wheel and a piston stop to find TDC. Align the dots as follows for each model.
250 - 52 degrees BTDC
350 - 47 degrees BTDC
450 - 36 degrees BTDC
Posted: Fri Sep 09, 2011 10:39 pm
by bobnorton
52 degrees advance? I don't think so, If you could start it the big end would soon knock out. Fully advanced about 40 is about the max I would think .
advance?
Posted: Sat Sep 10, 2011 4:01 am
by maelstrom
I did not use the word advance.
I was working as a mechanic on Ducati motorcycles, when these models were produced. At that time there was no information available on the electronic ignitions. This information was supplied to me by the factory in response to a telegram that I sent to them. This was my chosen method of verifying such details as quite often the information was unavailable or incorrect. To be pedantic, I am sure you are aware that the same ignition parts are used on the electronic ignition singles, but the timing gear is one tooth out on the smaller models, hence the discrepancy.