gearbox widths?

I am mucking about with a commando and have a couple of odd dimentions. I have a Quafe box, the top mounting is 3.175"wide, the bottom 3.293"both seem to be central to one another, the engine is 3.303" wide, where as the middle of the cradle, measured 3.315" between the iso mount and the swingarm pivot. i guess that 20 thou between them is considered okay? Does any one know why the top of the box is getting on to an 1/8" narrower? spacers or washers could be a solution.
cheers,

kickstart said:

Does any one know why the top of the box is getting on to an 1/8" narrower?

Click to expand...

Commando gearboxes should have an approx. 1/8" wide spacer (part 030023) between the casing and the cradle at the drive side the upper mounting.

http://www.nortonmotors.de/ANIL/Norton% ... 07&Part=34
Item [34]

The Atlas gearbox before the Commando lacked the notch in the bolt boss and fits even nicer to my mind. The point being there is no need at all for the relief notch which some designer thought would ease install and removal of gearboxes instead of adding meanness to the process. On my Quafe I'll epoxy spacers to allow snug hand motion to tension or move to remove. These gearboxes may of been pressed in the past and might of twisted in the cradle to splay it some down there. I'd attempt to narrow the gap if plate squareness would not be affected. Otherwise just space to allow solid nip up and fly with the wind.

the 1/8"gap does seem to look like the Norton spacer is needed. When I first looked at it I thought it wanted a thinner spacer sy 1/16" each side? I will put it on some sort of flat plate. I know the hole at the bottom or bottom mount might need to be sleeved as that ally part of the casting isn't as flat as I would like. The CMW engine spacer / substitute is 3.375" wide, fair bit wider than my engine or gearbox.
when the gearbox is in I think a long straght edge is in order!

Peel's Q-box is installed for mock up only right now so didn't pay attention to tight fit, just looked to see indeed there almost 1/8" gap to fill at the top with a custom spacer -that's not so thick its a turmoil to bang in place. Peel has thicker Alloy cradle same inner width as factory but found the cut out for the DS fouled the thicker Quafe case so had to grind some off both gb and cradle to allow it to shift to set tension-distances.

yeah, had to do the same with my cradle to get it to fit. looks a lot beefier?! I will check out the position of the spacer this w/end.

Hm, Ok glad its not just me, as a bit pensive to go grinding on custom cradle and fancy gear box. I don't expect much improvement in tranny endurance, just a vain thought Qaufe looked cool with the fin bosses -and my used one was cheaper than a AMC shell. Now I see its so covered up no one will notice but me. Its also got questionable bearing bores so will try to prefect Jim Comstock JBWeld solution. Its a stop gap item until a ITT gemstone inserted. I have one more factory shell to limp about on if I screw up the Qaufe.

Just to be the exception which proves the rule, I mocked up my gearbox installation last night, and there's no recess for the spacer on mine, which only arrived from Mick Hemmings a couple of weeks ago.
I just assumed it was a Quaife thing.

At least I've got a spare 1/8" spacer now... :roll:

There is no difference bewix an Atlas and a Commando shell but the notch/spacer unless feature on Commando part. The notch adds between $200 and $300 bux to get that special useless Commando case feature. i wasn't aware of Peel little gap until mentioned here and looked. I may have noticed it a year ago in hast to mock Peel up for Empire rally, but forgotaboutit. Vendors tell me its just factory attempt to make it easier to install/remove by freeing up the top more but I found Atlas moves just as easy once the clamp force relieved. Could just stick washer in my gap loose but that would add fumbles so will epoxy it on. Peels Quafe gets pained black then the tops of the ribs get polished to Al highlight, if anyone sticks their nose down that low, and suspect many will as they trace tubes and hoses and fittings below the toy submarine air station.

Just beware that running in lower gears slings lube out of the sleeve bushes and prevents any replacement till in 4th or sitting still. Not that big a deal unless spending most an hour of hi power in tights in 2nd/3rd joy rides below the ton.

what threw me out was the casting has witnesses or impressions of the slots on the top mounting, both sides and yet is 1/8" narrower. so I guess it was over tightened at some point. Still haven't got the pics sorted.