One other question - the clutch cover I have is grey coated pressed steel with the four brass nuts. The clutch action seemed a bit heavy before I stripped it. The springs I have measure 50.4mm in length with a wire dia of 2.35mm. Does this sound about right or should I order some smaller ones - and from where?
That sounds more like a pressure plate than a cover.
Does this help?
http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=522943The fitted length pressure in lb. ft. is per spring.
1.325" fitted length is with the nut tightened until spring bolt is flush with bottom of screwdriver slot. As coil bind can occur tightening more than the spring bolt flush with the face of the nut is not recommended.
definitions:
f.l. Free Length
ft.l. Fitted Length
w.d. Wire Diameter
c.b. Coil bind
57-1560 (650 4 spring clutch)
f.l. 1.975"
ft.l.= 1.325" @ 32 lb. ft.
w.d=.090"
c.b. = .790"
57-1830 (650 3 spring clutch)
f.l.= 1.815"
ft.l. = 1.325 @ 43 lb. ft.
w.d.= 0.104"
c.b.= 0.900"
57-4644 (750 twin 3 spring clutch)
f.l= 1.716
ft.l.= 1.325"@ 53 lb. ft.
w.d 0.115"
c.b. 1.025"
After Market
Emgo 88-57493 (replaces 57-1830)
f.l. = 1.755"
ft.l. = 1.325" @45 lb. ft.
w.d. = 0.104"
c.b. 0.865"
Barnett 501-86-03075 (old MT-75-3)
f.l. = 1.755"
ft.l. = 1.325"@ 45 lb. ft.
w.d. = 0.105"
c.b. = 0.865"
Precision Machine (not recommended for street use)
f.l. 1.886"
ft.l. = 1.325" = 72 lb. ft.
w.d. = 0.113"
c.b. = 0.965"