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dear sirs,could you please explain in plain english how to really set the magneto on a monza jr in the manual it says it should be installed with a specific angle between mark on flywheel and crankshaft keyway(32-36 degrees) the problem is my flywheel has two timing marks a hairline mark and a thick one on the left which of the two should i use,also the manual says(if installed incorrectly ignition voltage will be decreased) i wonder why is that so,could you please explain why,i'm not getting a good spark and a mechanic friend suggest i have to get the feed coil rewinded because it may be shorted due to old age thanks and best regards gener philippines

As it is not a steady voltage, but a varying one that swings from positive to negative, going through zero volts on the way, it needs to be timed so as to provide ample voltage at the moment the points open.
Suggest to try the mark that you think is most likely correct. If that isn't satisfactory try the other one.

Jordan

By: 10gener...
" could you please explain in plain english how to really set the magneto "

____ Well probably not in "plain" English, I'm afraid. ...
__ It's actually the magneto/alternator's flywheel-rotor which needs to be 'set' in a certain ('timed') relation to the crankshaft (and thus also the ign.points), as otherwise it likely won't produce near maximum power-output during the specific times when the ignition-spark has to be produced.
Within the 360-degree range of the 4-pole rotor, there are FOUR possible position-points (each spaced-apart by 90-degrees), that the rotor can possibly be pressed onto the shaft at, so as to be 'timed' for producing maximum power-output that's at-least sufficient for the times when the ignition-system happens to need it, (especially during low-RPM while kick-starting).
However, Ducati only located just ONE mark on the face of the flywheel-rotor (instead of at all four equally good locations).
It's somewhat of a mystery as to how & why Ducati chose exactly where to locate their timing-marks as they did, cuz the stamped marks have proven to not always be consistently placed in relation to the actual location of the magnets.
It would've been nice if Ducati itself had ALWAYS stamped the mark for alignment with TDC, (so that others would never need to bother with scratching-on their-own (TDC located) timing-mark.


" the manual it says it should be installed with a specific angle between mark on flywheel and crankshaft keyway(32-36 degrees) the problem is my flywheel has two timing marks a hairline mark and a thick one on the left which of the two should i use, "

____ The "thick one" is no-doubt the correct/original timing-mark.
__ Possibly somebody-else has already done as I always recommend, and that's to place a scratch-mark, (possibly your "hairline mark"), on the rotor at the TDC.point (same as where the shaft-keyway is located), so as to not loose-track of the original factory-set rotor-timing, BEFORE pulling-off the rotor from the crankshaft. _ That way, 'timed' re-installation of the flywheel-rotor is more easily done and it's proper timing is not lost !
If my assumed-guess is correct, then you ought to find that your two mentioned "timing marks" are spaced-apart by about 34-degrees. _ (Please let me know for sure.)


" also the manual says(if installed incorrectly ignition voltage will be decreased) i wonder why is that so,could you please explain why, "

____ Actually, if the flywheel-rotor (with it's four evenly spaced magnets) is-not installed properly 'timed' onto the crankshaft, then it's even possible that the magneto/alternator could happen to be 'set' to produce very near no power-output AT ALL, (when the rotor's magnets then happen to be located nearly 100% away from the particular point where & when they are needed to be), during the times when the ignition-system most needs power-juice to be produced,, thus there would then be absolutely NO ignition-spark whatsoever. _ But chances are, with the rotor installed randomly, there could then most-likely be just a weak ign.spark. _ That's why it's important to make-sure that the rotor-magnets's magnetic-fields are optimally located in relation to the ign.system's alt.power-coil (of the magneto/alternator-stator), during the brief moment in time when the ign.spark is needed to be produced (at nearly FULL-power when the auto-advance unit is fully retarded, during kick-starting).
____ There have already been a number of other threads posted covering such directly related issues as this one, in much greater detail.
If you desire more such related info, then try doing a search (here at this w.site) for them.
If you need help finding them, then please ask for help.


" i'm not getting a good spark and a mechanic friend suggest i have to get the feed coil rewinded because it may be shorted due to old age "

____ While a burned-up & partially shorted-out alt.power-coil/core is indeed a possibility, it's fairly doubtful that that's the particular cause of your weak ign.spark issue. _ It could be more likely that your rotor's magnets have become weakened. _ However, it's even much MORE likely that there are other possible faults, to be considered beforehand.

____ Let us know if setting your flywheel-rotor properly 'timed', helped improve your ign.spark-issue, or not.


Hopeful-Cheers,
DCT-Bob

sir bob,thank you very much for that very comprehensive explanation,it felt like listening to a lecture! i read it over and over again ,nearly memorizing every word of it, you're right the hairline mark is simply just a marker.the original timing mark is about 30 degrees apart from the hairline mark and points to the corner of the upper left dowel,well the spark improved a little,but hardly reaches a 1/4 inch gap.and it wont fire,using the kick starter ,we finally managed to have the engine running by push starting,you mentioned the possibility of weakened magnets is there a possible way to revive it,also may i have the chance to review the related posts about ignition problems,i really appreciate all the help that i can get,
best regards.gener

" thank you very much for that very comprehensive explanation,it felt like listening to a lecture! "

____ Well I must say that I much appreciate that YOU seem to appreciate MY post-wording, as I've been told that my chosen wording is usually too complex to be fully comprehended by most readers. - (It seems that so many readers these-days have too hard of a time with keeping their thought-processing all straight while reading sentences with over half a dozen words, due to today's rather common vast misuse of written/typed English-wording.)
I try to make-sure that my worded-thoughts can't be misinterpreted, but that then leads to extended wording which can be harder to follow (especially for those who're used to reading today's more commonly used simpleton-wording). _ So I often attempt to break-up my worded-thoughts by placing extra/unneeded wording within these ( ) marks,
in such a way as to make my sentences read properly either with OR without also reading my extra-wording within those notation-marks, (just as it's expected to be). _ Doing that is a fairly common-practice that's done so as to avoid various worded-thoughts from getting jumboed-up together & confused, as the reader can then have the option of just skipping-over the extra/added notation-wording that's placed within: ( <this pair of marks> ) .
I hope it now helps to realize that, and that I always purposely do it in a logically/thoughtful manor.


" i read it over and over again "

____ Sorry,, my post-wording has not been double-checked edited until after my posts have been signed-off with: "DCT-Bob". _ And-so before that, it's possible that my posted-wording may not state my thoughts exactly as I had meant for them to be understood.
__ I've now read-through my previous-post and came to realize why it would've needed to be read-over in order to make fair sense of it all. _ It DID have some poor wording (for best comprehension), so I've NOW got it properly edited. _ So if you read it again, it should now make clearer sense !



" you're right the hairline mark is simply just a marker. "

____ Then if it was purposely placed for any logical reason, it then was most-likely meant to indicate the rotor's intended * install-position with regards to the crankshaft's TDC.position.
(* Which may or may-not be tied to the rotor's ORIGINAL/factory-installed position.)


" the original timing mark is about 30 degrees apart from the hairline mark and points to the corner of the upper left dowel, "

____ I'm left to assume that you're meaning to indicate that the factory-placed timing-mark is 30-degrees advanced past TDC, when you've placed the "hairline mark" to be located at the crankshaft's TDC.location,, correct ?


" well the spark improved a little, "

____ It's quite possible that your flywheel-rotor is still not set optimally timed (for best kick-starting spark-production).


" but hardly reaches a 1/4 inch gap.and it wont fire, "

____ Please elaborate on exactly what you actually mean by that posted wording of yours.
Certainly you don't expect your Duke's ign.spark to jump a quarter-inch gap set at the spark-plug !?


" you mentioned the possibility of weakened magnets is there a possible way to revive it, "

____ If your (rather heavy) rotor can hold itself (plus a little more weight-pressure) against a steel-surface without slipping-down, then it's magnets are strong enough !
However if it easily slides-down (while stuck-against a clean flat/smooth non-alloy vertical metal-surface), then you ought to consider having it's magnets re-magnetized.
Other threads about having such servicing done have been posted in the past, (here at this w.site). _ Here's one (of several related threads) that may cover some related stuff which you'd possibly like to read of... viewtopic.php?f=3&t=23&p=86&hilit=flywheel+rotor+magnets#p56


" also may i have the chance to review the related posts about ignition problems, "

____ There's been a fair number of other such postings on related topics having to do with Ducati's non-battery powered ignition-systems. _ You could do a search (here at this w.site) and likely find many of them. _ Just enter related wording into the search-box (located near the upper-right corner of most pages here).
Let us know if you have any trouble getting desired search-results.


Hopeful-Cheers,
-Bob

hi sir bob,hope your doing fine,i noticed your location is southeast of lake michigan,hope you;re not affected by hurricane sandy!(wish i could bring you a cup of coffee) can i email you off the group for some non technical talk!Happy Haloween!hernandez.gener@yahoo.ca

hi sir bob,hope your doing fine,saw that your location is SE of lake michigan ,does that mean you're almost near the canadian border,which i believe was devastated by hurricane sandy! hope you didnt have any problems at all.(wish i could get you a cup of coffee to lighten you up)anyway just dropping by to say hello (can i email you off the record,just have some non technical matters to discuss,but also about ducatis) regards
hernandez.gener@yahoo.ca

sir bob,can i use a standard 175 piston(62mm) for for a 160 monza and rebore the cylinder,its hard to find a 1st oversize 160 piston,only standard ones are available and expensive while the 175 piston is priced reasonably,will it make a big difference with regards to specs,its the only last resort we can think of to improve the compression unless you unless you dis approve and make recommendations
cheers,gener

Hi Gener

i dont think the size of the wrispin is the same.

but what did i hear about your welded up half Ducati half Yamaha conrod ?

Eldert

sir eldert thanks for your reply,well sad to say,yes its welded into two parts, the upper part is a yamaha,with a needle type bearing,and i dont know why,i have to admit that i cant afford a new conrod,i'm also using an old piston,with fabricated rings,but i found a 61.5 piston on ebay uk,at a low price (mr.hitchcock of road and race has one but its $180!) i'm only a used car salesman here in the phil,and times are hard nowadays!especially now that christmas is just around the corner,i have to save for my grandkids presents and gifts.hopefully if the piston arrives early i can get the monza running just in time for christmas and it will be,just like a kid who got a gift from santa!
regards gener