Bottom bevel bearings.

[DewCatTea-Bob]

" found collapsed double row bearing,loose guides in head ,this was after about 500 miles from shop rebuild. "

____Clearly, that shop who did the work is little more than a crooked-thief !
It's quite certain that they had the upper bevel-gears un-properly shimmed so tightly that the special (dual-row) bearing was busted-down by the pressure.


" still strugling with outer race stuck it center of steel bushing "

____ For all such problems as that, I would always find a couple of suitably sized 1/2"-drive deep-sockets (or the like) to place on opposite ends, and put all three items together within a vice, and then press the race out & into the larger socket's cavity. _ (Warming the outer-most of the two stuck parts, helps lessen the amount of pressure needed from the vise.)
Can you try that?


" Do you use a set of ground loose main bearings to read crank float? "

____ No, I myself never have.


DUKE-Cheers,
-Bob

[Bevel bob]

I'll try the vice!, with such tight fit on shafts It can't be easy to read the play to achieve tight shimming on the crank.

[DewCatTea-Bob]

" The bearings would be a steal at that price! unfortunately they are $10 each plus packing,air frieght,insurance,import tax,etc "

____ That eBay-seller must have learned of the prices that you have to pay for them, because he has now raised his price from $10 for ten bearings, up to $80 for eight bearings !
I guess that's how you knew "they are $10 each" !?


Sad-Cheers,
-Bob

[DewCatTea-Bob]

" with such tight fit on shafts It can't be easy to read the play to achieve tight shimming on the crank. "

____ It seems that what you're meaning to convey,, is that the fit of the crankshaft within the inner-races of the two crankcase main-bearings, is so snug, that its hard to feel for any slop-space that requires added shimming between the crankshaft & crankcase main-bearings (of the motor-case).
If so, then you must need to have the motor-case kept completely stationary while you use both of your hands to slide the crankshaft side to side.

____ Scott has pointed-out the reasoning for using "angular" type bearings for the main-bearings...
Does anyone have any comments about using roller-bearing type bearings for the main-bearing locations within the crankcases?


DUKE-Cheers,
-Bob

[Bevel bob]

Its common practise to use a roller on the drive side to handle the loads and a ball on the timing side to locate the crank,I dont know why Ducati doesent do this,loads not enough to need it?,axial load better handled by a ballrace? The vice has done the trick,very tight though.

[Bevel bob]

Have not split cases yet ,they are resisting all my efforts, I will make up the wood puller you suggest. "slag bolts"?? These are terms used to describe the exit of an unpleasant female!!,can't be using such non PC language over here.Do you mean coach bolts??.____ AHA!! just looked it up, LAG bolt!! Loosely translated to English meaning Out of work layabout does a runner, or convict escape !!.

[Bevel bob]

Cases now appart, difficulty caused by corrosion between alignment dowels and ally case,the crank is well out ,bad workmanship.everything else looks ok so crank off to workshop and order bits and bob's for rebuild.

[DewCatTea-Bob]

" I will make up the wood puller you suggest. "slag bolts"?? "
" AHA!! just looked it up, LAG bolt!! "

____ Right, I had meant to type 'lag-bolt' !
Way more often than not, when I proof-read my pre-postings, I then see need for editing of my original wording and sometimes previous parts get left & mixed-in. _ Then I depend on a spell-checker to draw my attention to any left-over errors, but in this case, the 's' that got left in front of 'lag', didn't get flagged since 'slag' is also a proper spelling.
I'll fix that error when I next re-edit that post.
__ Lag-bolts are what look to be like machine-bolts except they have wood-screw type threads.


" Its common practise to use a roller on the drive side to handle the loads and a ball on the timing side to locate the crank,I dont know why Ducati doesent do this,loads not enough to need it?,axial load better handled by a ballrace? "

____ I can understand how the stock standard ball-bearing bearings can handle both the radial-loads & the axial-loads which the stock motor set-up exerts on it's main-bearings. _ And I know that roller-bearing type bearings handle radial-loads better than ball-bearings do ! _ However, I don't know how roller-bearings compare to ball-bearings when it comes to axial-loads. _ (I'm guessing that they're likely not as good as ball-bearings, in that regard.)
IF roller-bearings indeed have still sufficient enough axial-load capability for the job in question, then I'd prefer to use that type for the main-bearings.
I'd think that roller-bearing type main-bearings ought to be preferred at least within a motor which has straight-cut primary-gears.
__ Just wondering because, I was once advised that roller-bearings would be a superior choice for main-bearings in narrow-case motors. (As their stock main-bearings are undersized [compared to wide-case main-bearings].)


DUKE-Cheers,
-Bob

[Bevel bob]

Providing the crank is tightly shimmed a roller race would be ok but only up to 7-8 k revs as i understand that roller skid becomes an issue and shorter life can result.

[Scottish888]

I had to heat the steel case for the bottom bevel bearings to be removed with one popping out easily but the other involved a lot of heat to finally punch out the outer bearing case.
I am concerned about the best way to fit new bearings in, I really don't want to be hammering so hard on a new set of expensive bearings, any tips?
I used punches to remove but don't have anything of the near diameter to help me tap in new bearings, thinking to have to old outer turned down on a lathe and hit that.
I guess you remove the bearing inner's and fit in the outer, refit, fit spacer and repeat?
How hot should I heat the steel case to make the job easier? bearings have polymide cases.

Regards