Steering stem bearings

[BigOz]

I have some new billet yokes to fit as part of a bigger upgrade and when fitting the inner race the bottom of the stem I tested the fit before heating to the 120 Centigrade the service manual mentions. The bearing wouldn't even drop over the threads at the top of the new stem above the top bearing seat.

This leaves me with a question, as the top race is the same part number do the ID of the inner race will be the same how will this fit over the threaded portion especially as the manual doesn't mention heating the inner race of the top bearing? Anyone have any ideas?

Regards,

Andy

[Dukedesmo]

I would have thought it should go over the top section, otherwise how would you ever get the front end on and off?

When I've changed bearings I try to heat the outside part and freeze the inside, my 916 head bearings simply dropped into place this way but its easier on a 916 because the bearings go into a tube that fits inside the head so it is much easier to deal with when off the bike.

I have yet to change the Monster bearings but it's a job I've got planned, my Mrs just loves it when I've got engine parts in the freezer and the oven... :rolleyes:

[Dookbob]

I have changed quite a few head races on M600 and 620 models,and have never needed to heat anything up, I have always just dropped the inner race down the yoke tube and tapped it into place with a tubular drift. keeping the race square with the yoke tube is essential of course, and they do need a good thump to drive them home. If yours wont even go over the threaded portion at the top of the yoke tube, then its the wrong size bearing.

[Capo]

I have changed quite a few head races on M600 and 620 models,and have never needed to heat anything up, I have always just dropped the inner race down the yoke tube and tapped it into place with a tubular drift. keeping the race square with the yoke tube is essential of course, and they do need a good thump to drive them home. If yours wont even go over the threaded portion at the top of the yoke tube, then its the wrong size bearing.

Yup thats how I've done them.

Are you sure you have the correct bearings?

[Pomp1]

I have changed quite a few head races on M600 and 620 models,and have never needed to heat anything up, I have always just dropped the inner race down the yoke tube and tapped it into place with a tubular drift. keeping the race square with the yoke tube is essential of course, and they do need a good thump to drive them home. If yours wont even go over the threaded portion at the top of the yoke tube, then its the wrong size bearing.

Same here, just instead of a drift I've used a drawbolt. Quite a bit of effort to get them in but they go eventually. Freezing the outer race works well in some instances. How do they compare to the old ones in size?(with a vernier possibly?)

[BigOz]

If yours wont even go over the threaded portion at the top of the yoke tube, then its the wrong size bearing.


The bearing package has the part number shown in the parts pdf I have and the dealer I got them from was checking the numbers as I read them out so I'm certain as I can be it is the correct bearing.

I don't have a micrometer but my calipers say the top bearing seat has a diameter 34.96mm and the major diameter (OD of the thread peaks) of the thread above is also 34.96mm.

I'll check the ID of the bearings tomorrow as the inner race I have is now on the bottom of the spindle but another arrived at work today while I was away on a course.

Andy

[jerry]

Get tapered rollers upgrade rahter than standard Ducati rollers ,they last longer and improve handling .

[BigOz]

Get tapered rollers upgrade rahter than standard Ducati rollers ,they last longer and improve handling .

I did think about it but decided to hold off this time.

The bearing has an ID of 35.00mm so there is a little clearance but not much.

Andy

[BigOz]

Hi,

Well I'm half done, warming the bearing did the job I warmed it carefully so it felt hot but I could hold it witout pain or damage so I guess it was about 50 C.

Quick teabreak back at home now then back to the garage with a few more bits that need to go on.

Andy