Alloy Chain Cases on a 52 G9?

wilko · Post by **wilko** » Wed Aug 22, 2007 12:48 pm

you're makin' me nervous biscuit! i'm building up a project involving a 650 twin involving a b52 box with the alternator cases, but i'm committed now! i'mintending to use an amc clutch with said combo for the cush clutch., douglas

Biscuit · Post by **Biscuit** » Wed Aug 22, 2007 1:25 pm

I'm sure Jim will set your mind at rest!

jim501 · Post by **jim501** » Wed Aug 22, 2007 1:32 pm

Didn't have any clearance problems with the clutch basket/drive sprocket but then my bike has an AMC box (something else non standard for the year, should be a Burman) Alloy cases mate straight up to the crankcase and clear the primary drive/clutch OK. AMC clutch has shock absorber rubbers built into the centre so no worries about losing the face cam shock absorber on the crank. Alternator rotor/stator lines straight up. Can't imagine there would be a problem with a Burman box because the inner alloy casting is only about 3/16" thick at the back. Relating back to the original query about a G9, I would imagine the swap from steel to alloy cases would be just as easy. Both types would be sized to fit the crankcase spigot and the alternator cases certainly have enough space to accomodate the engine shock absorber if you want to keep it.

kind regards
jim

itma · Post by **itma** » Wed Aug 22, 2007 1:44 pm

how do you key the rotor onto the face cam type shaft? I always thought the alternator shaft was longer?
and what about the sprocket which is splined on the later shaft?Edited by - itma on 22 Aug 2007 12:47:00 PM

jim501 · Post by **jim501** » Wed Aug 22, 2007 6:41 pm

Well spotted, Itma. Perhaps I'm being a bit too simplistic. Yes, the primary drive sprocket is a floating fit, the drive is transmitted through the outer collar of the shock absorber. Remove shock absorber spring and discard. Refit with alternator rotor in place of spring and bolt up solid effectively locking the shock absorber collar to the sprocket. Always meant to weld the collar to the sprocket but nothing ever came loose, in five years, so can't remember whether I ever bothered. Alternator rotor was keyed to the shaft with a parallel key in one of the splines the shock absorber slides on. Thinking about it, the alternator rotor I used (Lucas) had exactly the same internal diameter as the splined outer section of the crank mainshaft but that is not to say that all rotors have the same ID. Perhaps some measurement would be a good idea before taking my suggestions as gospel.

kind regards
jim