Bearing puller?

Have a look at Fox McScrooge's MC28 vapour blasted cases . . . drool.

If you are going to use replacement bearings that are not genuine parts ensure that the internal radial tolerance class is correct. I have no idea what they are but probably standard. If they are not standard they will have a C# after the number (C2 are tight and c3 are loose). Standard tolerance have no C# marking. If for example the inner ring was a press fit on the shaft then the factory may have opted for a c3. Alternatively if the bearing was a loose fit on both the shaft and the housing then they may have opted for a C2. I used to fit different tolerance classes on Ducati single gearboxes because the tolerances between one set of cases and another were all over the place. Motorcycles often have c3 bearings in their wheels because they need the extra clearance to compensate for the inner ring compression that occurs after the axle is tightened. This is why correct tightening of axle nuts is so important and why the axle nuts usually have a locking mechanism eg split pin.
Snap ring bearings like your are suffix NR.

Since the bearing failed I would also recommend that you check the runout and fitted end float on that shaft while you have it apart. Bearings have a life of course, measured in rotations, but they usually fail for a reason. It is always prudent to go looking for that reason. Countershaft bearings often suffer from poorly adjusted/worn chains trying to rip them apart. Bearings are not expensive and it would be wise to replace them all. You must at least replace the one on the other end of the countershaft as it suffered a terrible load once its partner died.

In some cases it is worth considering upgrading the bearing to a higher performance class. In the case of these types of bearings the cage is made of a lighter material and the bearings will give a longer service life. FAG have a good range of these. See http://www.phufart.pl/_struktura/katalogi/FAG/KOSZYKI INFORMATOR TECHNICZNY.pdf
The polymer versions are quite acceptable and they are not that much more expensive than the standard steel cage versions. I always used these types of bearings, or even more higher spec, when building racing engines.

Sorry for my long winded stories but the 250 community represents one of my most significant customer groups, so I feel obliged to contribute something.
cheers
Blair

 

Ok here are some pics
These are polyamide cages. Quite cheap. I need to find some info on comparisons to steel cages. Good job for Mr Grey; he enjoys a challenge.

Edit: Don't use these as Polyamide is not recommended for synthetic oils or some oil additives.


and this is a phenolic resin cage

Most of these are C3 and P6 thus the P63 suffix. P6 is a very high precision class and you can expect to pay 5 times (my guess) as much as a steel cage for one of these. They usually don't come with snap rings (NR) but I use to get the snap ring grooves ground into them. You need to do quite a bit of research and you can usually find a brilliant bearing bloke somewhere. RHP use to have a great range of precision class bearings and I had a good contact in Brisbane who knew his stuff. I could call him up and bounce ideas off him and he would do special imports for me. Now I am in Timbuktoo
cheers
Blair

 

I have sometimes had success using a 'strap' type oil filter removing tool to hold the clutch while removing the nut. The cloth belt type work the best.

 

I have used a set of old clutch plates, just the inners will do but you can use both, to make those tools. You need to assemble them in the clutch basket and then carefully slide them out as an assembly. Then use some g-clamps to hold them together and drill a series of 6mm holes through them. Finally, cut out a piece of steel that looks like a giant bottle opener, and to the round end, you drill the matching holes that you can bolt the clutch plate set to. Job done.

I did a search and found a good pic of what it should look like. In this pic they have used both sets of plates. I always made mine like this too but I used six m6 bolts not three m8 to hold them together.


By the way a lot of the other pics I saw look like butcher's tools. This version will spread the load over the maximum area thereby minimising the risk of damage.
cheers
Blair