[Ducati] Bearing question
Ryan Scott Bardsley
bardsley at tixel.net
Wed Nov 15 09:06:21 EST 2006
Thanks for all of your insight. While I won't be competing in WSBK anytime
soon, it is very helpful to hear what the "concept" behind the "right"
bearing is. On my bike I can definitely see the areas that Ducati spent a
lot of time designing, engineering, and manufacturing. I can also see areas
that look like they were thrown together right before they shipped. Working
on complex mechanical designs for a living myself, I think I know how it
goes.
I purchased a set of SKF bearings from the company that I use at work. The
rep didn't know any specific details and fell behind the "use the stock
ones" shield. My bike was made in 1981...I would like to think that 25y of
bearing development has resulted in some advancement. Ceramic bearings were
about $350 - $470 each. A bit too pricey for my taste. The only other
options seemed to go with these:
Angular contact ball bearings, single row
Principal Basic load ratings Fatigue Speed ratings
Mass Designation
dimensions dynamic static load Reference Limiting
limit speed speed
d D B C C0 Pu * - SKF Explorer bearing
mm kN kN r/min kg -
35 72 17 31 20,8 0,88 12000 12000 0,3 7207
BECBM *
The main bearings to took out of the stock motor had a plastic or Phenolic
cage. The specs that I cross referenced the bearings to had ABEC1 ratings,
so I assumed that these would work as they were "normal" fit but they have
machined brass cages, not riveted ones.
Do these look ok? What are the important factors? Art? Rich? Alex? It sounds
like speed rating needs to be higher? What sort of crank speeds am I looking
at in a stock 650? (sorry, not sure if this is a 1:1 correlation with the
RPM) ... In general, is this rating synonymous with a higher ABEC rating?
Also, these bearings seemed to have a 40* contact angle which matched up
with the cross reference from stock. I assumed this was to match up with
trust vectors in that specific angle. Is this number also able to be
"improved" meaning, if I spent $300 on a bearing would it reduce that to 15*
or something?
Sorry for all of the questions, I just like to know what I am aiming for
when rebuilding this engine and I wish I had a bit more technical info.
Right now I am on the factory workshop manual that says "place the seals
back in the engine with utmost care" ... But then they don't include a
picture of where they ALL should go so it's a hunt through the big bag of
gaskets and seals to make sure they are all in the right places before
sealing the engine up! Details! I need details!
Thanks guys,
Ryan
Boston, MA
81 Pantah
On 11/14/06 9:43 PM, "Art Ramos" <hyperpastabiker at gmail.com> wrote:
> Hi Rich
>
> ABEC 9, Less than 500 for the pair, from two different manufactures.
> RHP's are made in England, http://www.ahrinternational.com/rhp_bearings.htm
> While the IBC are Swiss made.
> http://www.ahrinternational.com/ibc_bearings.htm
>
> Every Ducati I have seen with crank failure has had the stock bearing in the
> cases. Some motors where stock motors that had been spun up at the track.
> Preload and bearing quality struck me all so importantly. So I asked Guy
> Martin when he was machining my heads and we where putting Matt Smiths 996
> SPS together about bearings. He noted that John Hackett was using some
> expensive bearings in BSB and John had never had a bearing failure using
> these bearings. I'm thinking it's nothing for a inline four to sit a
> 10,000-13,000 all day long due to the smaller and evenly spaced power
> pluses. Now try that with a 13.8 or 14 to one compression twin! The bearings
> would play a major role in keeping rotational forces in spec and hopefully
> prevent the motor from tearing itself apart. I thought about the money
> invested in my motor and I didn't have a second thought about using them. In
> both of my project motors!
>
> My 996 main bearings have a plastic or Phenolic cages from the factory and
> are very well suited to the environment inside of our engines. My RHP and
> IBC bearings have the same. Brad Black had mentioned on another board that
> the newer versions had an extra bearing added for load. Ducati has never
> made a bearing in it motorcycle history. That dosen't mean they can't spec
> one either. We Desmoquattro owners do know what has happened when Ducati has
> subbed out rocker plating to others. Ducati did not invent the angular
> contact bearing, so more than likely a Ducati design M.E. sourced bearings
> from a known components lists. I'm sure this is exactly what Ducati did when
> designing the 916 Corsa cased engine. Being ducati they carried this part
> to the air cooled line as well this year.
>
> I think the stock bearings are now a 100 bucks apiece today so the cost gap
> isn't that substantial. When you do go to your local bearing house and spec
> these bearing, the parts guys about shit and ask just what your are using
> these bearings for. When I ordered and asked them what these
> bearing application was, they would throw their hands in the air. When it
> came time to pick them up, I'd ask again for the application only to
> find they'd spit out information like they just got out of bearing school! :
> )
>
> Maybe prices have dropped due to the Ceramic bearing rage? I don't know.
> I agree stock bearings would work fine for a stock 650 motor, maybe even a
> aftermarket bearing a grade higher if the price was right vs OEM prices.
> Upgrading never hurt anyone. : )
>
> If your looking for these bearings give Guy Martin of MBP a ring, I bet he
> has a shelf full of them.
>
>
> Hi Alex!
> Hey they don't even know who I am, and why in the hell would they want me in
> the first place! : )
>
>
> Art Ramos
>
> 2005 999R
> 1999 996 Mono (Frankenduc)
> 1999 944 SSie (Angryduc)
> www.hyperpastabiker.net
>
>
> On 11/14/06, Rich Roberts <bigredxrunner at yahoo.com> wrote:
>>
>> Oh sure, the question was for stock motor overhaiul so I answered
>> accordingly. I guess the problem with alot off stock bearings even
>> supposedly good ones like SKF likely only meet ABEC1 standard. You start
>> going to 3,5,7 prices go up accordingly. As I recall the stock bearings went
>> for 50-100 bucks depending on day, moon phase etc. I can not remember
>> anymore but seems to me every step up the ABEC ladder about doubled price.
>> As I also recall electric motor " Spindle" bearings for high speed motors
>> was often explored in auto sports as they are often ABEC 3 or 5 or even
>> better. You just dont see those bearings in big sizes very often as you
>> often do not see couple hundred horsepower electric motors turning at 20000
>> rpms. Most are at the high enough speed of 3600 rpms. Course that wont work
>> for engines. So when you go there you are talking about pretty special
>> bearings as a start. A medium sized 4000, 5000 series, 6000 series ABEC 5
>> bearing good for 20000 rpms is a pretty
>> fancy bearing in my book. A standard SKF/MRC which is not offically ABEC 1
>> even though it meets the standard in medium sizes is a 100-200 dollar
>> bearing. I would love to know more about those bearings you have Art just to
>> see how smart Ducati is about bearings for their WSBK motors. I really have
>> little specific knowledge of what they have been doing there. Rich
>>
>>
>> ----- Original Message ----
>> From: Art Ramos <hyperpastabiker at gmail.com>
>> To: Ducati Owners Group <ducati at ducati.net>
>> Sent: Tuesday, November 14, 2006 2:54:24 PM
>> Subject: Re: [Ducati] Bearing question
>>
>>
>> Hi Rich
>>
>> I have two sets sitting in the garage one set from RHP and another set of
>> IBC. Both sets are better quality than the OEM bearing that Ducati sells.
>> Read pricey here! You really didn't think that Ducati WSBK engines are
>> running the factory OEM bearings, right? I was told they are high load
>> thrust spindle bearing that where made to handle rpm in the range of
>> 20,000
>> rpm. So there are bearings to be had other than OEM. You won't find them
>> sitting on a shelf though.
>>
>> Art
>>
>>
>> On 11/14/06, Rich Roberts <bigredxrunner at yahoo.com> wrote:
>>>
>>> is it NTN? The right and left main crankshaft bearings are only
>> available
>>> from Ducati as I recall, they are special and are angular contact. You
>> would
>>> not want to use anything other than the OEM spec, meaning why go with an
>>> angular contact where there is no axial thrust? Rich
>>>
>>>
>>>
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>
>
>
> --
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> some of the most beautiful products ever for Ducati's.
> Visit http://www.cyclecat.com/
>
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