Clutch basket

[pear0]

My 250 came with a basket that was missing 2 "ears" . They were neatly cut off and on opposite sides so I put it in and it works. Engine does vibrate more thanI think that it should.
However I wanted to fix it and bought another basket The other day the lift was empty so I took the old one off and put the new on the shaft and discovered that it didn't mesh. Just happened to have a 350 engine sitting on the bench with the left engine cover off. My 250 has a 24 tooth crankshaft gear and the 350 has a 27 of larger diameter.. When I bought the basket on Ebay it was advertised as 250 /350. Is the 27 tooth a 350 part or is it just Ducati "diversity" ? TomA

[DewCatTea-Bob]

[quote= pear0 ...
" My 250 came with a basket that was missing 2 "ears" . They were neatly cut off and on opposite sides so I put it in and it works. Engine does vibrate more thanI think that it should. "

____ No-doubt after one ear-leaf got busted-off (likely by mishandling), the opposite-side one was then-next purposely knocked-off to compensate, (to obtain a rough 'balance' condition),, and whoever did it, apparently also cared enough about even more-so precise-balancing, to further bother making the leaf-stumps "neatly" identical.
__ But even if the leaf-stumps are left remaining in their roughly broken-off condition (with minimal stump-material left standing unequal),, the very-few grams of resulting misbalance doesn't really cause any significant additional vibration that notably stands-out from the normal eng.vibration, (unlike when only one ear-leaf is missing).



" I took the old one off and put the new on the shaft and discovered that it didn't mesh. "

____ Do you mean that your paired-up primary-gears didn't actually 'mesh' with each-other (as normally expected), or that the fitment spacing between their teeth-sets turned-out to be too sloppy to come-into proper mesh-contact ?
Does the "new" gear have 60 or 57 teeth ?
__ The pair of gears in the primary-gear set are 'factory-matched' for ideal compatibility,, so any (non-factory) pairing-up of either primary-gear with another prospective p.gear-mate taken from a random source (such as eBay), can then possibly result with a non-matched pairing. _ But even-so, such random pairing-up of non factory-matched primary-gears most usually doesn't end-up with their gear-teeth not being able to 'mesh',, but more likely instead, able to mesh but-rather in an inefficient semi-binding manor that consumes an unnecessary degree of power (due-to added interference-friction), (thus robbing some degree of power which would otherwise get transferred through to the rear-wheel). _ Or-else (less likely), rather be more noisy than a std.factory-matched primary-set.
__ So, I'd rather tend to recommend preferring the original 'matched-set' (with it's pair of missing ear-leafs) over a more pleasing appearing non factory-matched / randomly paired-up pair of primary-gears.



" My 250 has a 24 tooth crankshaft gear and the 350 has a 27 of larger diameter.. "

____ That's normal as expected. ...
__ The 350-engines produce more torque, so the primary-ratio was reduced (from 2.50 down-to 2.11:1) so as to relax torque-stress on the trans.gears.
And since the drive-gear's diameter consequently grew a bit larger, then of-course the 350's reciprocal primary-gear (on the clutch-basket) conversely had to correspondingly shrink in diameter to compensate (for still fitting within the same allotted shaft-spacing). _ So while the 250 basket-gear has 60-teeth, the 350 version has only 57-teeth !



" When I bought the basket on Ebay it was advertised as 250 /350. "

____ It's unfortunate that eBay's search-engine limitations lead-to their sellers taking-advantage of having their-own seller-listings become included amongst search-result page-lists by including additional/superfluous description-wording within their listing-titles.
So while it's certainly possible that your eBay-seller also didn't realize that the 250 and 350 don't employ the same primary-gear set,, it's fairly likely that if the eBay-seller is someone who's well familiar with 'Ducati-single' models, then the seller simply included '250' (and likely other unintentionally-deceptive description-wording [such as 'Diana' & 'DESMO'] as well) within their listing-Title, just for the goal of likely drawing more attention to their eBay-listing !
So such misleading eBay-seller title-naming practices ought be taken into consideration whenever pondering whether the eBay--Title-description is actually correct !



" Is the 27 tooth a 350 part or is it just Ducati "diversity" ? "

____ Yes, that's the drive-gear tooth-number size that's exclusively employed on all stock single-motors greater than 300-CCs,,
and any so-called/folkloric Ducati 'diversity' -(randomly-installed varied parts) is pretty-much mythical, (at-least so far as for Duke-models made specifically for the USA, go) !


Dukaddy-DUKEs,
DCT-Bob

[pear0]

Thanks Bob for all the info. Tom

[DewCatTea-Bob]

Thanks Bob for all the info. Tom

____ You're welcome, but you just happened to submit your post whilst I was in the process of editing my original post-wording, so you must not've yet seen it all.
__ Also, I'd still like to know exactly what you meant when you indicated that your paired-up primary-gears "didn't mesh" .


Hopeful-Cheers,
-Bob

[Jordan]

Might have been a typo, as it's the 350 and 450 that have interchangeable primary gears.

Jordan

[pear0]

"Didn't mesh" what I meant was that the 24 tooth gear and the basket from the 350 didn't quit reach each other. As the 24 is a smaller diameter than the 27.
I have a 27 tooth gear on the way to me. Any reason why the 350 basket and gear will not work on the 250 despite the reduced torque of the 250 engine?

TomA

[double diamond]

I’ve disassembled 250’s that had the 350 clutch basket installed. Racers probably thought the 350 ratio was an advantage? Also, the 350 clutch basket is steel while the 250 is cast iron. The steel baskets are more durable than cast iron. The issue you may encounter is that you may not have the backlash of the primary gears properly set. Ducati provided a range of primary gear diameters in order to set the backlash. This allowed compensation for variations in the center to center spacing of the crankshaft and input shaft as well as variations to the diameter of the driven gear. Matt

[pear0]

I will install it and check the lash. Maybe I'll get lucky. Thanks for all the inputs. Tom

[pear0]

Well I installed the 350 basket and gear. There is just a barely perceptible movement and it is much less than the former one with the missing ears. The bonus is that the engine vibration is much reduced and the bike is much more pleasant to ride.
I would question the theory that removal of the ear opposite the broken one and trimming them to equal level results in a balanced basket. Static balance maybe but not dynamic. TomA