A Clutch of Questions

[raypond]

G'day Charlie,

Did I miss something or did you just casually say you have a recco'd gearbox? Where from and how much? (if it's not rude to ask).

Cheers
Ray
'86 R65

[Airbear]

G'day Charlie,

Did I miss something or did you just casually say you have a recco'd gearbox? Where from and how much? (if it's not rude to ask).

Cheers
Ray
'86 R65

Not rude at all, Ray.
Gearbox cost $900 from Ross Gregory down near Dandenong (0421 057 488). I don't know who did the work (I totally failed to ask), and am still a couple of hours away from the first test ride. It looks nice.

Ross has a few other gearboxes in various states, and may know of others out there. He's a fair dealer with a good range of parts.

[ontic]

Hows things going Charlie, Still leaving for Melb Tomorrow?
I had a good day with preparations including a little work on the bike. New featherlite throttle and clutch cables installed, which are a vast improvement over my old notchy brickheavy cables. Also, just a little tweak of the mixture screw seems to have fixed that popping I had in the left exhuast on deceleration (finally!). She was feeling very sprightly on my ride home this afternoon.
I got a bottle of 5W fork oil today so I will do the forks tomorrow. Might go the whole hog and put on the new gaitors while I am at it.
A teeny bit more sewing to do, but other than that it is mainly packing and house work (to keep the girl happy).
Lots of snow up there lately, should be fun.

[raypond]

G'day Charlie,

I hope you're off riding around at the moment, you can read this when you get back.

I'm glad you got your gearbox from Melb and not from a bloke from up this way. He lives down the river a bit I think. I bumped into him at the Wagga Swap and he had a rebuilt gearbox for $400. I was very tempted until he told me that he had put a roller bearing on the front of the output shaft to overcome the problems caused when there is no circlip to hold the standard ball bearing in place (I had problems earlier this year - see old forum). Now he seemed to know his BMWs, and he claimed to have been a BM dealer in some other country at some other time, but I'm still not convinced about a roller bearing doing the job. Aren't roller bearings unable to take any axial load?

Trust you had a good ride.

Cheers
Ray

[Max Headroom]

G'day Charlie,

I hope you're off riding around at the moment, you can read this when you get back.

I'm glad you got your gearbox from Melb and not from a bloke from up this way. He lives down the river a bit I think. I bumped into him at the Wagga Swap and he had a rebuilt gearbox for $400. I was very tempted until he told me that he had put a roller bearing on the front of the output shaft to overcome the problems caused when there is no circlip to hold the standard ball bearing in place (I had problems earlier this year - see old forum). Now he seemed to know his BMWs, and he claimed to have been a BM dealer in some other country at some other time, but I'm still not convinced about a roller bearing doing the job. Aren't roller bearings unable to take any axial load?

Trust you had a good ride.

Cheers
Ray

Ray, amongst the cylindrical roller bearings, there are several configurations. One type has the rollers mounted in the outer race and allowed to float on the inner ring, while another type has the reverse with the rollers mounted on the inner race and floating in the outer ring.

The type of cylindrical roller bearing fitted to the front of the input shaft has a lip on one end of the inner ring, allowing it to float in one direction only. The lip enables it to take some axial load. Although nowhere near the axial load of a taper roller bearing, it's still quite adequate for the purpose. The big advantage is that the radial load capacity of a cylindrical roller bearing is near enough double a deep groove ball bearing of identical dimensions.

The other advantage is that the cyl roller brg cage is available in different materials other than pressed steel, and that presents a big step forward. The standard 6403 C3 bearing fitted to the front of the output shaft is only available with a pressed steel cage, and it's the cage that seems to cause a lot of the problems associated with common gearbox failures on non-paralever bikes. (The paralever bikes sometimes have their own problems). The special plastic cages such as the phenolics are better suited to gearbox applications IMHO, but in spite of an extensive search I've been unable to find a bearing manufacturer that produces a plastic caged 6403 C3. Brass cages are arguably better again, but price can become an obstacle, and availability is also a challenge.

I considered myself very fortunate when i managed to find a brass-caged 6403 on the shelf of a bearing company some years ago, and used it when rebuilding the 'box for my R90S. I also fitted an NJ304 C3 with a phenolic cage to the front of the cluster, with the same configuration as the front input bearing. Makes it much easier to assemble the gearset too.

Hope this makes useful sense!

[raypond]

Thanks for that Max (or should I call you Edison Carter?), so you're saying that the right cylindrical roller bearing would be an improvement over the stock ball bearing?

Cheers
Ray
'86 R65

[Max Headroom]

Thanks for that Max (or should I call you Edison Carter?), so you're saying that the right cylindrical roller bearing would be an improvement over the stock ball bearing?

Cheers
Ray
'86 R65

Ray, it depends on how the roller bearing conversion was done, to some extent. Bear in mind that the 6403 C3 inner race locates the helical 5th gear, so the choice of a suitable replacement gets trickier. There aren't any bearing manufacturers making a cylindrical roller bearing which directly replaces the 6403 C3 dimensionally, so any conversion requires either a flanged sleeve for the outer race or a flanged bush for the inner race. An outer sleeve would be preferable, and it was an option I was keen to pursue myself but I chickened out. I may yet give it a go for the next 'box rebuild . . .

[Jean]

There is a picture of worn splines in the really OLD Chilton's manaual I have...that says splines worn the way shown in the earlier photo are due to a misalignment between the engine and tranny.
I also noted in the discussion that the clutch parts were worn unevenly, so that matches with misalignment.
If this tranny hasn't been installed yet...I'd sure do some checking with a dial indicator on the flywheel,etc. and then a straightedge on various parts to see where the misalignment might be.
Runout between the outer edge of the flywheel and the mounting flange of the engine is given as 0.010 inches or less.
I wonder if this is the result of not replacing parts at some earlier time, that "looked OK" but really weren't?

[ME 109]

Airbear left a few days ago Jean. He will be back in ten days.

[Jean]

I recalled that just after the post, but maybe he'll get home OK and read this!!
Sure are a lot of clutch/tranny repairs going on just now...