Points Adjustment.

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Bevel bob
Posts: 1043
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Points Adjustment.

Postby Bevel bob » Sun Jun 06, 2010 11:26 am

With all the marks lined up,points at 15 thou theres not enough travel in the points backplate to achieve the timing, the only way it works is if I open the points up to 20 thou.Is it common to have to extend the slots? Perhaps i can advance the gear 1 tooth? Points gap also varies depending where on the cam its measured.

DewCatTea-Bob
Posts: 2897
Joined: Sun Nov 01, 2009 10:53 am
Location: Near SE side of Lake Michigan

Re: Points Adjustment.

Postby DewCatTea-Bob » Sun Jun 06, 2010 3:47 pm

" With all the marks lined up, "

____ Exactly what marks are you referring to?


" points at 15 thou theres not enough travel in the points backplate to achieve the timing, the only way it works is if I open the points up to 20 thou.Is it common to have to extend the slots? "

____ No, there should never be any NEED to extend the adjustment-slots in the points-plate any longer!
What timing-setting are you attempting to achieve? ...
Narrow-case Mk3 & SCR static-timing should be 22-degrees BTDC.
Stock battery-powered models should be 5 to 12 degrees before BTDC, and 450 models should be 0 to 4 degrees BTDC.


" Perhaps i can advance the gear 1 tooth? "

____ Perhaps you've assembled your particular gear-timing 1-tooth retarded?
__ Are you sure that you're working with all stock-type parts for your model?


" Points gap also varies depending where on the cam its measured. "

____ Of course, the points gap-reading should be taken when the points have fully opened right at the peak-top of the cam's opening-RAMP, which had just-finished moving them from their closed-position. _ And not taken while at any other area of the cam-lobe, (as doing that would likely create an unexpected points-gap).


Hopeful-Cheers,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob

Bevel bob
Posts: 1043
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Points Adjustment.

Postby Bevel bob » Sun Jun 06, 2010 8:50 pm

Hi, All the gear marks are as per the book, cant achieve the 5degrees static unless points openned up to about 20 thou,I did notice that the gear marking was out when I stripped it down. would not be surprised if wrong bits fitted. Does have Mach I type Auto Adv and battery ign.Points look standard.I'll try advancing the points gear 1 tooth.I'm using a timing disc and timing light and working with the head off for accuracy in setting disc.

DewCatTea-Bob
Posts: 2897
Joined: Sun Nov 01, 2009 10:53 am
Location: Near SE side of Lake Michigan

Re: Points Adjustment.

Postby DewCatTea-Bob » Sun Jun 06, 2010 9:50 pm

" Does have Mach I type Auto Adv and battery ign.Points look standard.I'll try advancing the points gear 1 tooth. "

____ Each tooth of the 30t point-cam gear will cause a 24-degree change at the crankshaft !
Afterwords,, for a Mach-I model, you should set the static-timing for 8 to 10 degrees BTDC,
as only "5" degrees BTDC is too retarded for a Mach-I.


DUKE-Cheers,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob

Bevel bob
Posts: 1043
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Points Adjustment.

Postby Bevel bob » Mon Jun 07, 2010 3:52 am

Hi bob, After a nights sleep I think I may have the answer, the crank itself is unmarked, and could be one tooth retarded,after all I havent yet checked the cam timing out with the disc which should give me a similar problem. In my books it gives the static timing for mach 1 as 5 to 8 degrees? .I checked the static before stripdown and it was 5 degrees ,other indicators showed the timing to be a couple of degrees retarded. Is there normally any crank marker apart from the keyway?
Last edited by Bevel bob on Mon Jun 07, 2010 4:29 am, edited 1 time in total.

Bevel bob
Posts: 1043
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Points Adjustment.

Postby Bevel bob » Mon Jun 07, 2010 4:27 am

After more thought, this is an ex-race motor and could have bits of any combination,I think the safest method will be to ignore all markings,set cam timing first with degree disc, get the ignition to work and scribe my own gear markers . Do you time a green white with normal clearance? What method and figures do you use ? ,my books dont give any settup info for this cam appart from openning and closing figures.

DewCatTea-Bob
Posts: 2897
Joined: Sun Nov 01, 2009 10:53 am
Location: Near SE side of Lake Michigan

Re: Points Adjustment.

Postby DewCatTea-Bob » Mon Jun 07, 2010 6:06 am

" the crank itself is unmarked, and could be one tooth retarded,
Is there normally any crank marker apart from the keyway? "

____ Yes, one of the crankshaft's 15 teeth should have a timing-dot in it's edge ! _ And it should be matched-up to the female-dot on the oil-pump gear.
The crankshaft's (male-tooth placed) timing-dot should be found near-about 4-o'clock, (with engine at TDC).


DUKE-Cheers,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob

Bevel bob
Posts: 1043
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Points Adjustment.

Postby Bevel bob » Mon Jun 07, 2010 7:56 am

No crank dot! perhaps been ground off? ,moved 1 tooth and spark timing now works,mind you the cam tming all looks a tad off now, but i intend to check that out properly next!!

frankfast
Posts: 231
Joined: Wed May 05, 2010 12:35 pm
Location: New York (upstate)

Re: Points Adjustment.

Postby frankfast » Mon Jun 07, 2010 11:34 am

I posted a recent thread regarding the same problem. I couldn't get correct ignition timing until I noticed a slash mark (one tooth off the dot) on the ignition cam gear. I used the slash mark and now static timing is achieved with equal adjustment, both retard and advance, on the backing plate. I'm told that the slash mark is for 450's only but seems to work on my 350 widecase Scrambler.

DewCatTea-Bob
Posts: 2897
Joined: Sun Nov 01, 2009 10:53 am
Location: Near SE side of Lake Michigan

Re: Points Adjustment.

Postby DewCatTea-Bob » Mon Jun 07, 2010 2:59 pm

" Do you time a green white with normal clearance? "

____ I don't believe that any DUKE-cam's valve-timing is meant to be taken/read with valves set at running-clearance !


" What method and figures do you use ? "

____ I've already placed a post concerning this issue before. _ The process of doing this job is a good bit tricky, and it takes quite a lot of work& figuring to finally discover the exact valve-clearance which yields the given factory-specs for any cam's valve-timing figures !
So rather, EITHER exactly double the running-clearance for BOTH valves, OR, set them BOTH with exactly 1mm of clearance... Then rotate the crankshaft slowly FORWARD (from power-stroke TDC) and take your reading as soon as the shim-cap on the ex.valve-stem can no longer be twisted by hand -(finger & thumb) between the valve-stem & rockerarm-tip, (for opening figures), and take your closing-figures as soon as the shim-cap can once again be twist/turnable.
Continue rotating crankshaft forward (ONLY!), and take opening & closing readings for the intake-valve.
__ The readings you get will not exactly match the given factory-specs, so you'll find that it's necessary to at-least double-check the whole process before you can be sure you've taken your readings correctly.
After you're satisfied that you got consistent readings, let me know what timing-figures you've come-up with, and then I'll tell you what's-what.
__ This job can be a real-big head-ache if ya try to get it done under time-pressures,, but otherwise if ya have the spare-time -(a couple hours) to do it, it can then be somewhat rewarding/fun !
Looking-forward to seeing what figures you get with your G&W-cam ! - (There seems to be two different cams which are both referred to as "Green & White" .)
Is your camshaft out where you can mike it?


Hopeful-Cheers,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob


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