4 spring clutch

[a101960]

I have ordered a set of new springs. When I dismantled the clutch all 4 springs were different lengths!!! Strange to say though, that despite this oddity, the clutch actually functioned OK (albeit a little on the heavy side). Now, what I need to know is, when I fit the new springs how far should the spring retaining nuts be tightend down?
John

[bsa-bill]

Hi John
I have found this to be a bit of "how long is a piece of string" thing, last time I did it the studs didn't make it through the nuts, will depend on the thickness of plates, spring length (various manufacturers ),
 never done this myself but some say, front wheel up against a wall and tighten the clutch progressively until the engine stalls when the clutch is engaged.

[a101960]

never done this myself but some say, front wheel up against a wall and tighten the clutch progressively until the engine stalls when the clutch is engaged.

Bill, that is a novel if a bit brutal idea.
John

[duTch]

  I'm on with B-Bill and the length of string - but haven't gone further that way.....plenty of options posted.......I've been using the bean can (or bit of pipe/zip-tie) on the lever to hold it in and crank the kicker (or engage top gear and turn rear wheel) to get the plates run-out even-ish, then, dump the bean can/? and screw in/out until the drag is about half way-ish out....you'll get the hang after a couple of goes

[BSA_54A10]

Also messy but the only way to go
You can do the same thing using the kickstarter.
The trick is to keep the clutch as light as humanly possible which reduces wear on the bike as well as your wrist.
BSA's instructions give you a clutch that does not slip when you are pulling a double adult chair with a Rhino in the front & a hippo in the back with an elephant as pillion.

[Black Sheep]

And of course there are two weights of clutch springs available.

[JulianS]

The choice of lever also makes a difference.

The original Amal levers came with 2 different pivot to nipple centre measurements;

1 1/16 centres give less lever movement for more movement at the clutch end at the expense of a more sudden and heavier clutch.

7/8 centres gives more lever movement for less movement at the clutch end giving a lighter more progressive clutch at the risk of a dragging clutch.

[Sluggo]

Thanks for posting that and confirming what I have long suspected and wondered about.  I KNOW on the Triumph-BSA-Norton late style lever assys from the 1970s (With the large lucas switch assy attch) that there is some with an alternative cable and pivot design that is very sought after.

I learned this at the 2016 INOA rally as I brought  pile of those types of levers and some misc parts and books to sell.  A Astute and wise man went thru the pile, bought a few and THEN edu-mah-cated me, I know now certain ones of those command top dollar on FeeBay.  But I was okay with it, that one went to a enthusiast/nutter and helped put fuel/petrol  in the tank for the return journey.

On Sportsters and Buells theres a Mueller "Easy pull clutch" kit that goes on the clutch basket with the ramp, and turns them into a 2 finger featherlight clutch.  On Norton C-dos (That style clutch is also used on a number of belt drives) there is a trick of getting the clutch stack just right as well for the leverage and a light setup as well.
See: https://www.oldbritts.com/ob_clutch_info.html

I realize thats not strictly BSA but its helpful to know some of the methods used as well as if you build a custom setup IE: belt drive or?

It DOES make a huge difference on the clutch springs of the 3 spring-4 spring later type unit clutchs (Triumph-BSA) as there is multiple springs out there, as well as I believe for unit singles so pay very close attention to the part number if known.  I have installed the wrong ones and shocked at how stiff they can be,, or too loose-light.  I have felt that the springs are a time change item and worth having a few sets as spares

[bikerboy]

I am pretty sure you do this all on the kickstart. You wind the screwss in until they are about level with the studs.

You then pull the clutch in and kick it over making sure the pressure plate is turning reasonably squarely, adjusting screws in and out as required.

Then while kicking it over you slowly let the clutch just under halfway out the clutch starts to bind and by 3/4's of the lever being released the engine is turning with virtually no sign of clutch slip.

Thats how I have always done mine anyway, if there is a better way I will gladly learn it