5 speed trans rebuild Q

[wirespokes]

I'm doing a five speed for the first time and have a couple of questions.

First - is there a list somewhere of the bearings and their number designations? I know all about the 28 ball 3205 AC3 and the 6303. What are the others?

Second - is there any standard setting for the selector adjustment? You know, that concentric bolt on the back cover.

I've watched the youtube on MIKE'S MACHINES and it gives the important bits, and then there's another called Moto Guzzi LeMans 3 Trans overhaul.

All my bearings look good and the measurements are good except the output shaft that needed .007" shim.

[jrt]

Pete Roper wrote up a couple of descriptions about the transmission and shimming it to eliminate the 'clunk'. 
They are housed on the archive section of a different website.  I won't post direct links, but googling: "Gearbox, The Shimmin' Fix by Peter Roper"  and "Rear Drive Tear Down by Pete Roper" should bring them up.
In addition, Greg Bender (bless him!) on This old tractor hosts the old Guzzitech.dk archives and there are some transmission rebuild tutorials there (might be the same as above):
https://www.thisoldtractor.com/guzzitech.dk/gb_en_complex-technical.html

[Antietam Classic Cycle]

Bearings: https://www.thisoldtractor.com/moto_guzzi_loopframe_transmission_bearing_cross-references_-_5_speeds.html

My way of adjusting the shift selector is to simply lay a straight edge onto the face of it and bisect each of the "circles". Line up the straight edge with the center of the selector shaft, the center of the hole in the selector, and the center of the hole in the rear cover where the shift drum shaft inserts.

Are you replacing the shift return spring? The originals are failure prone up until the latest version. New reproductions don't fit correctly without a bit of tweaking and o.e. Guzzi springs seem to be hard to find.

[wirespokes]

Thanks, jrt! You know, Bender seems to have everything - but I don't always find it.

Thanks for that Charlie. I'll have to read carefully through your explanation again. I'm not picturing it yet, but that's just me. Ok - after reading through your explanation some more, let's see if I get it:

The idea is to position the two 'fingers' of the selector equidistant from the shift drum pins. By 'drawing' a line between the center of the selector mounting hole and the shift drum mounting holes, then position the 'fingers' between that line.

I have a feeling this transmission was opened before as the shimming was good except for the one shaft that needed .007". Also, it has the newer shift detent with the flatter profile and the hole in the center. I've also heard that if the spring isn't broken it's best leaving it. It's funny that the airheads had this same problem. Because of all that, it seems possible the spring has already been replaced. Anyway, do you figure it's wisest replacing the spring with the new ones available these days, which, it sounds like from your message, aren't oem but aftermarket?

[John Croucher]

 Replace all the bearings while you are in there.  $20.00 is cheap peace  of mind.

[Antietam Classic Cycle]

The idea is to position the two 'fingers' of the selector equidistant from the shift drum pins. By 'drawing' a line between the center of the selector mounting hole and the shift drum mounting holes, then position the 'fingers' between that line.

I've also heard that if the spring isn't broken it's best leaving it. It's funny that the airheads had this same problem. Because of all that, it seems possible the spring has already been replaced. Anyway, do you figure it's wisest replacing the spring with the new ones available these days, which, it sounds like from your message, aren't oem but aftermarket?

A little more complicated than what I do but achieves the same thing.

If your spring looks like this, then it might be okay:





If it looks more like this, then I would definitely replace it.





It looks like Harper's may still have the o.e. spring in stock:
https://harpermoto.com/products/shift-return-spring-28238261

Other suppliers will likely only have an aftermarket part.

Replace all the bearings while you are in there.  $20.00 is cheap peace  of mind.

Where are you buying "all the bearings" for $20?  Just the 6303 ball bearing can cost nearly that.

[wirespokes]

Where are you buying "all the bearings" for $20?  Just the 6303 ball bearing can cost nearly that.

Ok - I get the idea then - just haven't duplicated your easier way of doing it.

Yeah, I was wondering too about $20 for all. I paid about half that on ebay for a good quality 6303. The 2-row bearings are what - $50? $60? Each! And the others don't look cheap either - especially since some are only available through the dealer according to Greg Bender.

[Antietam Classic Cycle]

Ok - I get the idea then - just haven't duplicated your easier way of doing it.

Yeah, I was wondering too about $20 for all. I paid about half that on ebay for a good quality 6303. The 2-row bearings are what - $50? $60? Each! And the others don't look cheap either - especially since some are only available through the dealer according to Greg Bender.

When I get a chance, I take a photo of how I do it.

Finding the double-row 3205 bearings with 14 ball in each row and metal cages is never easy for me. I normally don't replace the bearings unless they're obviously defective (run rough) or have plastic cages.