Commander gearbox

[re5rotary]

Hi questions coming thick and fast! It seems I may have to go inside the gearbox of my recent purchase. To be fair the previous owner did say there was something wrong with third gear and looking at the bits on the magnetic plug something is not happy inside. I have a photocopy of a workshop manual that came with the bike but it looks like a 'draft' copy as there are handwritten notes and additions and worst of all no photos. Is there a better workshop manual about or was that all that was available? Is there a manual somewhere that deals with the gearbox assuming it is based on something else? Is it possible to rebuild the gearbox in place or does it and the motor have to come out?
Im trying not to restore the bike just get it tidy and running but the more I look the more I find and its rapidly coming to pieces

regards Terry

[Richard Negus]

As you note, the engine must come out before the gearbox internals can be accessed, and before that, the primary drive must be dismantled.
A better guide to this is the Interpol 2 Workshop Manual, published by Norton, which includes illustrations and technical data. This is still available from Andover Norton, part number 00.4228 and occasionally pops up on Ebay too.
Third gear pair are the usual culprits for tooth wear. As one of these is NLA, you can replace them with third gear pair from the Triumph T140V box. Norton and Triumph tooth profiles are marginally different so you must replace the pair.
From my experience, this is just the beginning of an adventure. Good Luck!

[re5rotary]

Hi Richard thanks for your help and advice regards Terry

[re5rotary]

Now I have the gearbox apart it seems 3rd gear is the least of my problems. The mainshaft bearing had collapsed and virtually every gear has damage. It seems layshaft 4/5 gear and layshaft 1st are also not available new, does anyone know if they are interchangeable with any other model?
regards Terry

[Richard Negus]

Terry,
The rotary prototypes started out with T140V gear set, but Norton went their own way and strengthened all the gears and shafts with several variations of material, heat treatment, and even tooth forms, making nothing interchangeable with the Triumph items.
The layshaft is a manufactured assembly, where the two gears are fitted, layshaft 5th being a selective press fit on the shaft, and the needle bearing sleeve located with a hidden wire circlip. The sleeve is then ground to size after pressing onto the shaft.
Getting 5th and the sleeve off the shaft requires a big press.
The result of this complex procedure is that layshaft 4th and 5th were never available as individual spare parts.
Layshaft 5th (the big gear) is a three-dog gear in the Commander. Earlier models such as the IP2, started out with a Triumph 4-dog gear and the matching 'Star of David' fixed dog. That Commander gear is not compatible with your mainshaft 1st unfortunately.

Probably you best bet is to try Startright; Graham may have use-able parts in his stores.
An alternate my be someone (Hi George!) who's discarded his original box in favour of something from the Orient.
R.

[fogrider]

I have a Commander box and swinging arm I will never use now. Richard did look through it for me quite a while ago and I seem to remember most was OK but with some slight degredation on a couple of gears. Maybe Richard remembers ?

Terry (the East Yorks one ! )

[Richard Negus]

C'mon Terry, (the E Yorks one), I have trouble remembering what I'm supposed to be doing sometimes, so the chances of remembering your gearbox internals are somewhat slight - unless of course I took photos.
That's why I take so many photos of engine strip & rebuilds. Then all I have to do is remember where I filed them .
R.

[johnbirchjar]

Like Richard suggested,try George M (in Devon)I think he had two IP2's for "breaking" and just throw another box in there,must be easier than trying to "Mix and Match" ,and speaking from experiance,during the first engine re-build I asked Malk Stanly if he could source a pair of 3rd and 4th gears,which he did,and they were fine (for about 500miles) then 4th was as noisy as the old one so I have learnt to live with it J.B.

[re5rotary]

Im happy for new or used parts whatever I can find to get a workable gearbox. I searched for George M to send a PM to but I couldn't find him? regards Terry

[johnbirchjar]

George is a ROC member so I am sure David "C" will have his contact details,J.B.

[Richard Negus]

NZ Terry,
There's an email and a PM waiting for replies when you're ready.
R.