That imaginary big gearbox :-)

[Nortonash]

I imagine that this would be the end cover of the 'big' gearbox ? It is very rough sand cast.

[Richard Negus]

That's the one!The same joint face as the standard one, but with the gearchange spindle coming out at the pivot point for the quadrant rather than further back.

[Nortonash]

Richard, you dont happen to know if the gearchange mechanism inside was basically the same as the standard box do you?

[Richard Negus]

And there brain fade sets in; Bob Rowley will remember much better, I'm sure.I think the cam and ratchet quadrant were the same, but the selector forks were certainly different. The ratchet arm was different in that it included the gearchange lever spindle.I seem to recall a totally different selector mechanism, designed by Doug Hele, which operated by a sliding hook Japanese-style; don't recall if it was used on the race bikes though.R.

[Wayne]

Hi ashThere are two variants of big gearbox linkcages, i have the the earlier big gearbox cover (polished) either 88 or 89 with the selector internals fitted to the cover, i can use mine with small or big box, toothed quadrant type mechanisemsI have photos of 89 Rcw sprays bike with std road type covers and 88 Rc and 89 rcw both nations bikes with modifyd road type cover to this type with the std hole blanked off as my own is, all fitted to big gearboxes. From 90 on they went with this type cover and a revised selector setup, (note as you dont have the std gearbox hole this is the later 1990 variant or there abouts) the v2 selector mechanisem had pins not teath on the camplate, the lincage to the camplate was not a toothed pivot as per the road bike it was a weard bar arangement, this may means the cover you have may have had origonaly a differant mechanisem to std (the cover part part of the v2 lincage is the only part i have not seen).Take a photo of the other side of the cover and i will compare it to mine, but that means nothing with norton race shop stuff, we striped my small race gearbox and richard noticed it had a couple of gears slightly differant to what he had seen beforeAs richard says bobs yerman on gears and boxes,

[Nortonash]

Thanks for the info Wayne. Here is a shot of the inside of the cover and another of a couple of the alternative selectors.

[Wayne]

Hi AshThe cover differs from my earlier big box cover and as discribed above your cover is for the v2 selector setup. You have two identical arms that act between the missing mechanisem in the cover and the pind selector cam plate pins, however the small bar part that acts on the pins is not in the picture. The two arms that you have are not compleat.Your cover dose not appear that it will take the v1 selector (wich was modified for the big box ), i will print the picture off and recompair. i am 95 percent certan you are going to need all of the v2 selector mechanisam to use this cover. In my experiance you can only partly identify race stuff by pictures as the team made continual dimentional changes that cant be picked up in a photo only by side by side comparrison or when its put together the parts dont fit because they are not a match set.Regards Wayne

[Wayne]

Hi AshThe above photo catagoricly proves the big gearbox or rc/rcw small box wont fit staight in to a f1 frameThe qaderant has less offset than the std quaderant, correct for the wide center box, however its also longer if this is correct my wide center casting has had the camplate hole bored out of line or thers another quadrent or its a v2 castingm, i dont think its a v2 casting though. Note the std road quadrants offset is way too deep for the wide center box)The only true way to tell is to compair the parts or anothe box.You can see the differance in selector mechanisems, the modifiod one is done properly with an oil seal, whats not evident is the skim on the miller to provide leaver clearanceYou can see the differance between the early race box and the wide center or as some call it the big gearbox. Bob Rowley may wish to comment on the divfferant mechanisms ect, for those interested in pirkins book theres a picture of a big grearbox with the moded cover on the RC588 without a faring. these were used in 89 as well.Regards wayne

[Nortonash]

So abit of machining to geta Commander type gearbox to fit the F1 frame then? Thats no problem, chop a bit off here, add a spacer there, its all part of the challenge

[Nortonash]

This looks to be a complete selector Wayne ?

[Wayne]

Hi Ashlooks like the arm is compeat however, is it the same length as your other 2 less the pivot pins, the porton that acts on the camplate is missing.

[Wayne]

So abit of machining to geta Commander type gearbox to fit the F1 frame then? Thats no problem, chop a bit off here, add a spacer there, its all part of the challenge

joking asside, some of this work is quit pressision enginnering a fact that someone lost on the rcw i bought. Its the gearbox top bolt part of the casting thats the main problem, its not solid so cannot be cut down to fit the f1 frame, the frame bracket that would need moving over. . My small gearbox has certanly been on a large rotary table to machine the left hand swinging arm bearing part of the casting down. The fit of the swinging arm, frame and gearbox is down to a couple of thou. spondon could weld a new top on the gearbox to match the frame, they did this on the nrv/f1 gearbox. Thers also chain alingment to consider when mesurements ar takenNote the race aluminium swinging arm spindel is to short for the F1 frame if you have one, i dout it would stand up to road use anywayRegards Wayne

[Nortonash]

Yeah I know it wont be that easy but I have plenty of time. Do you recognise this little bit, I assume it is another part of the wholegearchange mechanism?

[Wayne]

hi ashcant say i recocnise it, however i have not seen the outer cover mechanisem for your gearbox. I would be interested to know if your main wide center shell has a part number. its not garenteed any gearbox parts will mix and match together?Regards Wayne