B31 clutch & primary drive

Started by BeenyBoy, 13 February, 2018, 17:38:23

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BeenyBoy

A little advise please-

I'm trying to rebuild the primary drive and clutch on my B31 (M m series gearbox + 6 spring clutch)

Inner chain case and sliding plate fitted -
-felt and cork washer behind the splined sleeve-
-2 row bearing and rear plate onto the sleeve

all as per service sheet and manual- but when I fit the clutch centre and tighten the mainshaft nut it tightens down but leaves the chain wheel loose and- for want a a better word "wobbly"- Further tightening of the nut results in the clutch centre becomes fixed and will not rotate

I cant see what I'm doing wrong- as the order of assembly is as per the worksheet and I cant really see how else it can fit together- what am I missing ?

any thoughts ?

 
B31 (1955)-C11G (1954)-B175 (1971)-C11 (1949)

LJ.

If I remember rightly there always was an acceptable amount of wobble with the six spring clutch. Draganfly improved on a better bearing which is a solid aluminium ring with two rows of ball bearings, I found this a considerable improvement, however on my B33 I eventually replaced six spring clutch to a four spring, for better. My m21 from six to an even better believe it or not, single spring.

BeenyBoy

Thanks LJ...  I'll give that a coat of looking at- I find that if the centre is tightened down there is about eighth inch forward and back free play on the chain wheel- but this largely disappears once the  springs and cover are fitted; Everything will rotate although all it feels very tight. I'll strip it down again tomorrow and have another look
cheers
B31 (1955)-C11G (1954)-B175 (1971)-C11 (1949)

LJ.

Hi Beeny, The six spring clutch requires a LOT of patience in getting it right and it can be done as I have once found, and it was a good un for a long time until it eventually needed adjustments, and taking apart it then it became a pig and was never the same again, which is why I swapped for a four spring clutch... never looked back. One would have thought that six springs would have been much more even than four, I could never work out why the four is better though.  :o

ANDY HIGHAM

I have a 6 spring clutch on my B31, it is light, frees off well, does not slip or drag and was not made by BSA

20160221_114636_zpslshptepm by Sigma Projects, on Flickr

BeenyBoy

Thanks- Stripping and rebuilding it (again !!) and I think I've ascertained what the problem is- I think that the centre sleeve -and/or the shaft - have worn so that the when the centre nut is tightened the sleeve is hard up against the casing -or final drive sprocket- which is why the cork washer is crushed and it is difficult to rotate the clutch centre when tightened up - so....the answer is........ answers on a postcard ...to....this is going to be Expensive !!!!
B31 (1955)-C11G (1954)-B175 (1971)-C11 (1949)

ths

Andy that clutch looks impressive, where did it come form please?

ANDY HIGHAM

The inner drum, basket and pressure plate are Suzuki GS850 shortened by one plate. The sprocket is a standard plate sprocket fitted with a ball race onto a modified BSA centre. A modified rusty old BSA inner drum unites the Suzuki drum to BSA centre

20151116_210940_zpsvoqppleh by Sigma Projects, on Flickr

20151115_190402_zpslfisfmsi by Sigma Projects, on Flickr

20151116_211017_zpsobynshqb by Sigma Projects, on Flickr

20160215_085908 by Sigma Projects, on Flickr