How do you know if you need shims on clutch?

Hi,

having sorted out my gearbox i am putting the primary side on....how can i tell which (if any) shims my clutch needs? (with the naked eye, i would say clutch basket and crank sprocket look well aligned with no shims at all). In the Norton Parts book there are 2 shims illustrated, but both have the suffix "AR" which i presume means "as required".

Up front on the crank there are also 2 shims illustrated. What purpose do these shims serve...are they just to position the stator, or are they also for nut tightness?

timsha said:

Hi,

having sorted out my gearbox i am putting the primary side on....how can i tell which (if any) shims my clutch needs? (with the naked eye, i would say clutch basket and crank sprocket look well aligned with no shims at all). In the Norton Parts book there are 2 shims illustrated, but both have the suffix "AR" which i presume means "as required".

Up front on the crank there are also 2 shims illustrated. What purpose do these shims serve...are they just to position the stator, or are they also for nut tightness?

Click to expand...

Shimming determines how the teeth on the clutch hub allign with the teeth on the crank sprocket. Get a straight across them and get them as close as you can. Make sure you are snugged up a little to get a good reading. If you do not need any, then you don't need any.
Shims on the crank are for positioning the rotor. It seem you could be off a mile there and still have full functionality, but again, why tempt fate.
Although the triplex chain is forgiving, you should not tempt fate.

The least difficult way to do this (is anything on a Norton actually easy?) is to remove the inner primary chain case and put the 2 sprockets on their shafts, snugging up the nuts. Then it's fairly simple to get a straight edge across both sets of teeth. However you do have take into account the rocking of the clutch basket...

/Steve in Denmark

The triplex chain can take as much misalignment as is possible no problemo in the way Norton made-designed primary parts to fit so the main purpose of shims is to prevent clutch basket rubbing the inner case, so inner case alignment is as important as clutch shaft shims. Idealy best to square up chain with shims then shift - shim inner cover center mount to clear basket. 2 caprenter squares on sprocket faces are a good guide but over kill on loosey goosey chain links alignment so mainly a clutch basket rub reason. Belts must be spot on or walks off -wears apart.

Thanks for you're replies!
My clutch basket rotates without touching the inner case and the sprockets appear to be well aligned so i will do without the shims.

just don't leave out the washer that captures the "c" clip

That special washer is recessed on one side which is the circlip side. Hobot is right ,alignments are forgiving on the triplex but belts far more important.

Ta.

needing said:

When you mentioned rocking of the clutch basket I recalled having this problem on my 1972 bike. To hold the clutch centre firmly, I had a lock tab washer and nut and the clutch would rock even when correctly tightened.

I have since discovered that later Nortons came with a washer fitted to do the same. It is NORTON COMMANDO CLUTCH CENTRE NUT WASHER OEM 06-3447 (re: Andover model & part search).

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All Commando clutches should have a washer under the clutch centre securing nut. If your '72 model didn't-then it was missing?
Washer 040374 (from '68) for unhardened centres, and 063447 for hardened centres-plus tab washer, 063459.

http://www.nortonmotors.de/ANIL/Norton% ... 08&Part=58

Why leave the chain alignment to chance when you have everything apart now? As suggested, all it takes is a metal ruler against the sprocket teeth. It would be a good time to check the shimming on the center stud behind the inner primary case too. With the inner case held in place, you can tell whether to add or subtract shims by seeing if the case rocks horizontally or vertically. It is a good idea to put an extra clutch shim, if you have room, before the mainshaft circlip goes on to help keep the outer sleeve gear bush from walking out and rubbing on the circlip.

If the chain is not aligned it will wear faster and so will the sprockets. It may tolerate gross misalignment sure but that shouldn't even be part of this discussion.

I did a lot of things half-assed and just wrong when I was 21 and first got my Norton. Some things have only been set right recently. It's much easier and cheaper to study up and do it right the first time.

Ta.

needing said:

04-0374 is a spring washer?

Click to expand...

Apparently so, although the size often quoted for this washer is: 5/8 x 1-1/8" which is larger O/D than the standard spring washers I can find currently being sold as 04-0374?

http://baxtercycleparts.com/index.php?m ... s_id=10832

http://www.nsamotorcycles.co.uk/04-0374 ... 4537-p.asp

As much as this 'perfect' chain alignment sounds so smart and wise to seek its essentially non-sense advice for 2 reasons. 1. If parts not damaged/missing its impossible to assemble with enough chain mis-alignment to matter a whitworth as the triplex chain innate lateral link slack will shift in operation much more than a few thin shims can amount too. 2. In operation [beyond barely creeping] the shaft flex causes more tipping-wobble out of square than shims lateral distance can compensate for. Even in alignment sensitive belt drives it way more important to get the pulley's parallel to each other than in same centered drive plane. In other words shims only matter for stuff rubbing and do nothing to correct or stabilize the tipping of sprockets or pulleys. In belts the width of the clutch basket teeth allow belt to self center on crank pulley as long as the pulleys don't tip-wobble too much. Shims are for rubbing issues, not alignment to protect chains or belts. Sprockets alignment is determined by engine and gear box mounting in cradle, then shim to clear. Not saying its not good "practice" to get sprockets aligned best you can but that its merely an emotional feel good unreasoned "practice" w/o much or any mechanical reasons to do so. If worried about chain life then put in light wt-grade lube not engine oil [unless ES tensioner] and never give much throttle on upshifting and don't cut throttle sharply on down shifts. Someday will put a key chain video on road going primary to put some teeth in hobot "non-sense" conclusions.