CP clutch B52 gearbox

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56G80S
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CP clutch B52 gearbox

Post by 56G80S »

No panic. I'm planning on putting the B52 back into the 56G80S next winter. I hope I can find the crank axle spacer!

I want to refurb the AMC that was in when I bought the Matchless; I refurb'd the Burman a few years ago but didn't get on with it.

But after searches, checking Christian's Archives I think I was using a CP clutch with the GB box. The clutch I had got nice new plates, centre, springs etc for has a chainwheel with slots in the outer rim for tags on the (can't remember which) plates. A bit like the AMC clutch and the B52 ones I see are a continuous band with raised ribs on the inside towards the clutch centre.

Apart from an awkward episode when the clutch centre nut came loose (that had happened sometimes on the AMC box and so I was familiar with it and cured it) the clutch seemed to work OK. I also read that I could use the AMC clutch with a spacer.

I'm really looking ahead the focus over the next period is to sort out the suspected broken piston ring in time to get to the Jampot but if anyone's got any thoughts, they're welcome.

I plan a "complete" strip down in the winter. There are several jobs to do; I've done a heck of a lot of miles with that AMC box; the front forks and Jampots are due a revisit, I want to review which camwheells I'm using as I think I'd like to put the SH exhaust cam back in, it seemed to pull better that way with a standard inlet, maybe replace the rusted original Dunlop front rim etc.

Johnny B
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GOLDSTAR
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Re: CP clutch B52 gearbox

Post by GOLDSTAR »

yes you can use the AMC clutch with the burman box but you do have to turn up a spacer for the mainshaft which reduces it's length a tad, the problem then arises that it is not possible to get a lock washer behind the centre nut so I used locktite etc, I had to use an available burman box on my 57 G80cs but as there is no engine shock absorber it was necessary to use the AMC cluth as there is one in the centre.
I guess, should you use an AMC clutch, you will have two absorbers, wonder if that would make the transmission smoother? kind regards
56G80S
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Re: CP clutch B52 gearbox

Post by 56G80S »

Got the two shock absorbers at present as have the AMC box and clutch fitted; replaced the AMC clutch centre rubbers about 8,000 miles ago.

Yes, it's smooth.

What I really wanted to confirm was - following the description in original post, was I once using the CP clutch with the B52 box and if so would it make more sense to get a GB clutch?

Johnny B
Radcap
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Re: CP clutch B52 gearbox

Post by Radcap »

Instresting ? Im the other way round . I have a good amc box and want to fit it instead of the burman box . Can it be done ? Its a 1950 18c 500 ridged
So i can repair the burman
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spookefoote1956
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Re: CP clutch B52 gearbox

Post by spookefoote1956 »

I've got a CP clutch with my B52 box, they work fine.
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
56G80S
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Re: CP clutch B52 gearbox

Post by 56G80S »

Chris

Thanks. The work on the engine is going to cost quite a bit. For a start soda blasting the filthy head, a spare piston and the ex valve £80, sleeving at least 120, new piston 110, boring out? In the winter I expect quite a bit of cost on the front forks and plan to refurb the Jampots (2nd time after 20 years) as I suspect there's little oil left in them.

So could do without buying a new clutch (which the CP one is anyway). I didn't do any special mods the first time, should I have done?

Johnny B
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spookefoote1956
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Re: CP clutch B52 gearbox

Post by spookefoote1956 »

cp clutch goes straight on
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
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