primary case spacer

[nimrod650]

what is the reason for the large circular spacer on primary case

[Billybream]

Its to aid alignment, this is a quote from an improvements feature on A10s.

There are several different spacers listed that can be inserted between the engine and inner primary case.
The spacer is not listed in earlier parts books, later books do show it. The spacer should be used in all cases, without the spacer the oil seal groove on the clutch bearly engages the alloy slider in the inner primary case.

[Rocket Racer]

Keep in mind BSA fitted a range of engines to the swing arm frame (with only minor variations to the frame such as the kink added for the singles), unlike the plunger frame which was unique to the semi unit motors.

The swing arm pre unit motors were a regression from the neater original semi unit design used in the plunger models, but allowed more parts sharing in the range with the singles.

I'm not sure whether in putting together various semi common parts to form a bike (Bits Stuck Anywhere) the factory simply added spacers here and there
or
whether by adding a steel spacer this was intended to stiffen the rear chain case attachment to the motor. Every inner chain case I've seen is warped - they are a long case and poorly supported.

[ellis]

Just fitting a new SRM clutch to my 1960 swing arm A10, and I find that the inner chain case to the outer chain case at the rear I have a gap of about 3/16th of an inch. There is no provision for a spacer as the inner chain case lug is touching the frame bracket. Is this gap acceptable or do I remove some of the lug face aluminium to make both cases mate together without any stress on the inner case. (or am I being too fussy.

[nimrod650]

Just fitting a new SRM clutch to my 1960 swing arm A10, and I find that the inner chain case to the outer chain case at the rear I have a gap of about 3/16th of an inch. There is no provision for a spacer as the inner chain case lug is touching the frame bracket. Is this gap acceptable or do I remove some of the lug face aluminium to make both cases mate together without any stress on the inner case. (or am I being too fussy.

were the cases a face to face fit no twist on inner before you fitted them

[ellis]

Haven't tried that yet. I am waiting for my new clutch to arrive hopefully for the weekend along with the 6 spring puller. When I get the inner case of I will try the two cases together and let you know what I find.

[Rocket Racer]

Once you've got the inner case off, put it on a piece of glass with some grinding paste and check how flat the front engine side of the inner cover is.
As the cover is only held by two flimsy bolts when the front three screws are off the case is usually not flat.
As I mentioned these covers are long, so in my experience are always warped to some degree.

[chaterlea25]

Hi Ellis,
The SRM clutch may (will) sit farther out on the gearbox shaft than the old 6 springer
Have a read of the post I wrote on setting up the primary alignment
Your inner case sounds as if well distorted

http://www.a7a10.net/forum/index.php?topic=9646.msg70166;topicseen#msg70166

HTH
John

[Rocket Racer]

The steel plate between the engine and the primary cases is only to align the cases, it won't help you with clutch alignment issues...

[ellis]

You were right Caterlea25, both the inner and outer cases were distorted badly. Inner case had a gap of 60 thou and the outer had a gap of 35 thou checked on a face plate. 220 wet and dry paper stuck down with spray adhesive on the plate and a long day filing and rubbing the cases I now have a perfect inner and outer cases. Hard work but well worth the effort. Just one question regarding the SRM clutch basket. There is a raised center boss that doesn't allow the first plain clutch plate to sit flush with the bottom of the basket is that correct? Oh on asking SRM about primary chain case oil they were adamant that the oil should be 10/40 or 20/50 engine oil, and the capacity is 190cc just there to lubricate the chain. (can of worms maybe)

Cheers ELLIS 

[chaterlea25]

Hi Ellis,
I am assuming that your SRM clutch is the type where the inner drum does not have a lip at the inner edge
and the shaft adaptor incorporates a thrust washer ??

If so then the first plate that goes into the basket is a friction, check that it sits flat against the inner face of the outer drum,
Photos are in the link I posted earlier
This is the modified design as used on late Triumps/A65s, the spring pressure is no longer concentrated against an unsupported  plain plate at the back of the pack,

I use 10/40 castrol motorcycle oil in the primary, suitable for wet clutches, others prefer ATF ???
Car oils can contain anti friction additives that will cause clutch slip

HTH
John

[ellis]

Hi John,

The basket does not have an inner lip and the shaft adapter does have a thrust washer for the roller bearings. However SRM's instructions say the first plate into the basket must be a plain steel plate followed by a friction plate etc. I will speak to them in the morning to check that there instructions are correct. I can see your point about the friction plate going in first. The gearbox shaft nut they supplied is not the correct thread so will need replacing. I have Castrol 10/40 in stock so will be using that in the chain case. Yes as you say the plain clutch plate is only supported on the inner edge of the drum if that goes in first. I will keep you in formed.     

Cheers ELLIS

[ellis]

Hi John, I Phoned SRM this morning to ask about fitting the plain clutch in the basket first. They said they can understand my concern but this was the way to load the basket. I did say the first plain plate looks like it would flex not sitting flat in the bottom of the basket. So I will take their advice and see how the clutch operates. (fingers crossed)

Cheers Ellis

[chaterlea25]

Hi Ellis,

 

Attached is a link to a 65o triumph parts book,
go to page 32 and the assembly sequence is shown, friction plate first

http://classicbike.biz/Triumph/Parts/1970s/1970PartsManualTriumph650s.pdf

If a steel plate is fitted first it will cause steel to rub against  steel  as the plain plate is splined to the inner drum,and it will rotate relative to the chainwheel when the clutch is disengaged
I cannot see whether the steel plate will fall off the back of the inner drum and rattles around in there 

 

John

[ellis]

Hi Chaterlea25,

I see what you are saying regarding the Triumph center hub, putting a plain  plate in first would drop straight into the bottom of the clutch basket. The SRM clutch center hub has a  2.5mm thick ridge at the bottom of the splines so that when the first plain plate is dropped in it cannot drop of the hub  into the basket. If I new how I would include a photo just to let you see the way SRM machine their hub. I do appreciate all your help on this John. If some one could post a picture of their center hub I'm sure it would become clear to just how they work.

Many thanks ELLIS