Burman B52/GB G-6-2, gear, driving, mainshaft

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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56G80S
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Posts: 3354
Joined: Wed Oct 12, 2005 10:45 pm
Location: N YORKS UK

Burman B52/GB G-6-2, gear, driving, mainshaft

Post by 56G80S »

Yes, I've searched but no answer to these queries, as follows:

a) I have a maybe 1/20" of end float on the G-6-2 gear. I rebuilt the box several years ago, bushes, bearings worn parts replaced etc. I ran it for a few thousand miles with no problem except once the adjuster in the pressure plate unscrewed itself, easily remedied. I used a CP clutch at the time, as that's what I had. I then put back the AMC box that was in when I first bought the G80S. During a break in chemotherapy (which process has been arduous to say the least) I am checking stuff ready for reassembling the G80S and plan to use the Burman as the AMC is tired.

I have clamped the bottom mounting in the vice and test assembled everything to make sure I'd lost nowt! Everything runs true, no run-out or difficulties. Gears select fine as they did previously. However, I noted that the 19-8-18, bush for mainshaft driving gear is slightly proud of the end of the gear. With the end float at it's extreme outboard and the G-35-2, sleeve for mainshaft fitted the gap between the end of the bush and the sleeve is small, a couple of thicknesses of A4 copier paper (couldn't find feeler gauges! Or feel the ends of my fingers). Should I be bothered? I could file off the maybe 1/64" of "oversail" but it would be a faff.

b) I noticed that one of my clutch springs is longer than the others! I wonder if I've managed to mix in a 5 plate spring with a 4 plate set? Though I've forgotten how many plates I'm using!!!

c) I guess the tightness for the large nut for the gearbox output sprocket is "tight" not "very tight" seeing as how it's only a shallow nut; have locking washer. Just to outrage the purists, I'll be using a very good fit box spanner that Dad left me for this job.

Cheers

Johnny B
56G80S
Member
Posts: 3354
Joined: Wed Oct 12, 2005 10:45 pm
Location: N YORKS UK

Re: Burman B52/GB G-6-2, gear, driving, mainshaft

Post by 56G80S »

Thanks to Mick Davey for mailing me about his clutch spring lengths etc.

I've been to the lock up and the CP clutch centre appears to be for a four plate clutch, although the studs are 2" therefore fit a 5 plate clutch; 5 plates won't fit. It seems that the Burman spring length is the same regardless of the number of plates? 36-6-1? Anyhow I plan to replace the springs as a set as four are 1+1/2" and one 1+5/8", keep the studs and put a spare plain plate in to make two under the pressure plate as that was how I ran it before.

The clutch push rod is bent in more than one way so that's to be new as well. The bent one is 10+3/16 but I plan to buy a 9+7/8" plus an extra ball. If it's too short, I'll bung the extra ball in to bring it back up to 10+3/16".

Need to start re-assembling the Matchless but not until my next chemo rest week, 27 March and need to MoT the Yamahaha that week as well. Would be good to ride Matchless to the Jampot.

Johnny B
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