Checking NC engine bearings...

[blaat!]

How do I check a bearing?

If it rotates smoothly, and I can't detect any play, does that mean it is fine? Is it given that I should just replace the bearings while I have the engine apart?

Once I determine that one is bad, do I need to pay top dollar from a Ducati parts specialist, or can I just buy new ones from McMaster? For anyone unfamiliar with McMaster, they supply parts and stock material to industry next day, nationwide, and carry only high quality products. I checked and they carry many of the NC sizes and the prices seem good. Anybody know if there are minimum load, RPM, or ABEC ratings that would be required?

Thanks.
-Jim

[DewCatTea-Bob]

" If it rotates smoothly, and I can't detect any play, does that mean it is fine? "

____ I wouldn't say "fine" for sure but, it's likely still good enough for further use (in something not as important as a Duke).


" Is it given that I should just replace the bearings while I have the engine apart? "

____ YES, (when the cases are already split),, cuz even if the stock-bearings are in a motor which was always kept merely as a show-bike, those originally installed bearings were of questionable quality, even way back at the time THEN ! _ So if you're in any position to replace those old/stock bearings with modern replacement types, then it would be smart to go-ahead & do so.


" do I need to pay top dollar from a Ducati parts specialist, "

____ Only if you wish to help support them staying in business.


" or can I just buy new ones from McMaster? "

____ Any place that supplies modern name-brand bearings ought do, and if you find a place that better meets your budget, then why not ?


" Anybody know if there are minimum load, RPM, or ABEC ratings that would be required? "

____ I believe that all the bearings only require std.duty,, yet Today's-standard is superior, so in any case, you'd be effectively upgrading in a way anyhow.


Duke-Cheers,
-Bob

[wcorey]

Check out this post for a list of standard n-c bearings...

viewtopic.php?f=3&t=294&p=1888#p1858

Bill

[jbcollier]

They're not very expensive, just get new ones. Get a 2RS bearing for the tranny output shaft and pry out the seal on one side.

[Bevel bob]

Most,but not all, have to be C3 clearance, a free spinning bearing with no obvious play can be clapped out, spin a new bearing and hear the difference, take extra care at the gearbox output area, the case is easily damaged,take extra care with bevel gear bearings and the steel bushings that must not turn in the alloy housings,use an oven and the freezer , crank shimming is critical , dont closeley shim a 5 speed selector drum,above all take lots of time.( learn from MY mistakes).

[blaat!]

Oven and freezer, eh? I'll have to get a lesson on the oven controls from my wife... maybe she can give me a hand with this phase of the project

" do I need to pay top dollar from a Ducati parts specialist, "

____ Only if you wish to help support them staying in business.

I assure you, I'm doing that already!

Thanks for the tips. I'll be doing them one housing at a time and probably asking questions along the way.

Anybody ever use a hot plate like the workshop manual recommends?

-Jim

[ecurbruce]

If your ( wife or signicant other) is resistant to you using the kitchen oven, the outdoor gas grill is also an oven. One with a thermometer in the lid works well for all kinds of heating projects, including removing cylinder sleeves @ 400 degrees.
Bruce

[blaat!]

The BBQ grill is a good idea, my grill is right by the basement door. If I wait a couple months I can just leave the bearings outside in the cold New England weather. I can put a piece of aluminum sheet metal down first so I don't get grill marks on my gasket sufaces I have the workshop manual which specifies temps for bearing removal/replacement. I'm very interested to hear about your experiences with the removal - once the cases are brought up to temperature did the bearings just fall out, did you need to tap lightly, or did you need a press to get them out?

This is my plan:

· Work one housing at a time and try to do the removal followed by the replacement in one heating
· put the bearings in the freezer a day ahead of time
· Do a dry run and set up blocks, jigs, proper diameter drift, or whatever I need to have a good setup for holding the housing and tapping the bearing out
· Bring the oven/grill to the proper temp and then place the housing inside for 10 minutes or so
· Take the housing out, remove the bearing(s), and then put it back in the oven/grill for a few minutes to bring it back up to temp
· Take the housing out again and install the new bearing(s)
· Let it cool to ambient temp

Anybody have other suggestions?
Thanks.
-Jim

[ecurbruce]

Jim,
Yea, sounds like a good plan,...
Couple of things, clean the grille good prior to heating parts, so clean parts don't get all smoked up.
When I cranked up the grille, I put the parts in right away, so grille and parts heated up slowly and at the same rate, so not to heat up crank case to quickly... Don't know if it matters.
When cases come up to temperature,( I'm thinking 220 degrees, double check that, it's been a while) yea, the bearings come on out with little effort. Some fell out, some need a little prodding.
After new (ice cold) bearings are installed, put cases back in grille, turn grille off , close lid, and let it all cool down slowly together.
Oven mits work well for parts handling...
Good luck,
Bruce.

[Bevel bob]

I think 10 minuits is not long enough 15 at least , oven gloves--- i never thought of that , they go well with a pinney though