Is it a friday bike? - (Bevel-gear Alignment-concern)

[Bevel bob]

The ground areas on my top bevels meet perfectly however they are the only ones that do.All the other teeth show a constant step.Maybee it was time to go home and they didn't bother to shim the gears before grinding, what would you think?? Ignore the ground areas and re-shim? Or am I just an old septic skeptic!!

[ccambern]

Is it possible that the gears came from two different motors? Or maybe some other goof at the factory? I guess if I had to choose, I'd prioritize lash over matching the flats.

[DewCatTea-Bob]

" The ground areas on my top bevels meet perfectly however they are the only ones that do.All the other teeth show a constant step. "

____ Not real clear on what you're saying here.
Are you only referring to just the upper bevel-gears in the head? Or the lower bevel-gears (at the crankcase) as well?
__ If the 'grind-marks' exactly match-up (as seen under a magnifying-glass), then the bevel-pair is indeed a 'matched-pair' from the factory.
__ When properly shimming a bevel-pair,, not only must their common-plane surfaces be aligned -(the "lapped" area exactly flush), but also there should be NO lash-slop while yet completely meshing FREELY !
To get that complex arrangement properly done, re-shimming BOTH bevel-gears may be required using a full set of the various related shims.
____ Please let us know exactly what your noticed issue ACTUALLY is, and whether your cyl.head is installed or off it's motor.


DUCATIly,
-Bob

[Bevel bob]

Installed , free running and nil clearance and yes ground areas meet perfectly however as the rest of the teeth are distinctly out of step you have to wonder?. the only way to know is to "blue" the gears and look at the mesh contact areas. (this is the cam bevel).I'm also having a rethink on the bottom bevel bushing , to get the alloy housing to nip and hold the two bearings and spacer down will require a 30 thou gasket, new gaskets are 40thou which allows bearings,spacer and bevel to jump up and down 10 thou witihin the bushing , Top racers get around this by not fitting any gasket and glooping the joint.There must be a better way.I'm making a 10 thou packer to sit between the thrust washer and ally housing, but i expect i'll still have to use gloop as the bushing does not sit flush with the case.(another factory cock-up?).I understand that this beautifly designed motor was assembled by bored women thinking about their love lives.

[DewCatTea-Bob]

" ground areas meet perfectly however as the rest of the teeth are distinctly out of step you have to wonder?. "

____ Okay then, I guess it's clear what you've been meaning to convey about your bevel-matching concern.....
Your bevel-pair is properly shimmed for correct bevel-alignment quite well enough, but, you're still concerned as to why the edge of a portion of the teeth on one of the two mating bevel-gears remain slightly overhung past the equivalent edge of the other bevel-gear which it's mated with, (by maybe a few thousandths), all the way around except for within the one spot where both bevels were ground-away (the very slight-bit) by the factory. ...
__ Well it's ONLY THAT particular area/spot (where both bevel-gears have there common-plane ground-down together), which really matters to make sure are COMPLETELY flush !
Therefore if the rest of the way around is still left with their common-plane surfaces held a bit off from being 100% flush, then that SEEMINGLY misaligned-portion is actually of no real concern,, just so long as the bevel-pair is meshing freely & without ANY lash-slop !


DUCATIly,
-Bob

[Bevel bob]

The home made 10 thou packing has done the trick and i can move on, and I won't worry about the top bevel question --lifes too short.If i have the crank out again in the future i'll definately transfer a crank shim to the timing side as having no shims behind the crank bevel will make any future adjustment a pain.The problem caused by wider mains or crank radius/ mains clearance on the timing side.Piston circlips with one ear are availiable from Lacey Eng .

[DewCatTea-Bob]

" and I won't worry about the top bevel question "

____ That you've stated that leads me to think that perhaps you're still left unsure about it, and that would mean that my previous explanation was not clear enough to be correctly understood.
So I read what I had written and realized that more wording could have been used to help you keep my intended conveyance on track. _ So it has now been edited for that purpose. _ Hopefully it will now make better sense for clearer understanding.
The bottom-line is that I believe that you have your upper bevel-alignment done correctly and that the small misalignment-appearing issue which you were concerned with about it, is not abnormal and can be ignored.
__ Apparently Ducati did not bother to produce both bevel-gears to have their common-plain machined EXACTLY the precise distance from center needed to have the 45degree-plane on both gears end-up PERFECTLY flushly-matched. _ And so that's why the factory had to 'mate' the pair on a jig and then grind-down a common-spot on both TOGETHER at once, thus 'MATCHING' them for later expedited installation.
And now here you've come-along and have taken advantage of the factory-worker's grind-job, once again,, just as was originally done at the Ducati-factory way-back when that matched bevel-pair was first assembled into your classic DUKE-motor !
How really nostalgic is that !?!


DUCATIly,
DCT-Bob