I thought the gearbox would be pretty straightforward, I would post a few pics and not have much to say about it. I found there are several things in the RE gearbox, made by Albion, worth noting and I have detailed them in the following post.
After everything was taken apart it was cleaned and inspected to determine what could be reused Vs replaced. The S2 only had 10k miles on it and everything looked pretty good. New ball bearings were ordered along with all of the seals and sealing washers. My friends on the Royal Enfield Interceptor Yahoo group told me about a great 5 part tech series on the Albion gearbox by Don Morley. This is located on "Hitchcocks Motorcycle" website in their "Technical Notes" page. It is a must read for an Albion rebuild. Great history is covered too......a lathe gearbox....who knew?
A good read for an Albion re-builder.
Through this article I learned several key things. The layshaft bushings leave the factory with a +.001 spec on the diameter. There is no "out of service" spec given that I could find but the manual says to replace the bushings when movement of the shaft is excessive. What is excessive? A member of the RE group told me that +.0045 is a spec used on other brit bikes for a reference. Mine measured +.01 which sounds excessive but movement of the shaft was minimal so I decided to keep them as is. If the box is noisy I will replace them and consider it a learning experience.
The cases were cleaned via soda blasting. I like this method as water removes all the grit when finished. It also removes minimal material keeping the finish close to original. Screw heads were hammered and filed back into shape and cases buffed to where they were when they left factory in June of 1969. Threaded holes were chased with taps.
A couple of noteworthy points to make at this step. There are two gears that are very similar and cannot be interchanged. One is on the layshaft and one on the mainshaft. This is discussed in the Albion gearbox article mentioned above. The second point regards the oil thrower washers. They must be installed with recesses facing away from the bearing they surround. One was correct on mine and one was backward. Corrected and on we go.
New bearings and a "heavy service two way seal" installed in place of the standard single lip seal. It has a metal casing and heavier rubber sealing lip. I have not used these before but it looks like it may be a good option.
I did not find the Albion tech article until after I disassembled my gearbox. If I had I would have marked my shifter plate location before removing it. Bummer for me. I found a method to set this up on the web. The pivot arm must be centered to the plate attachment fittings (mounts with thin nuts). If things do not shift I will revisit this setup. Another area to watch is the gear operator plunger. If this is too tight it will cause stiff gear changes. Too loose and it will pop out of gear. It must be aligned properly too.
Everything reassembled and moving through the gears well. Neutral finder works too. Time to put it on the shelf until the rest of the bike catches up.
A controversial topic to dive into is which oil to use. There are many good points made in support of various positions. I have used Valvoline 75/90 Full Synthetic gear oil on my brit bikes for years and will continue to do so. Study the topic and take your positions.....proceed at your own risk....
Yet another sidetrack. The Trophy rear shock gave up the ghost last fall several weeks after the rear end was taken apart to change the tire, chain, and sprockets. With 50k miles on it I can't complain. I purchased a Hagon from Dave Quinn Motorcycles in Connecticut, moved the wife's car out of the garage, and went to work. I have some trips in mind and I think the Hagon will make them more enjoyable.