The BSA A7-A10 Forum

Technical => Clutch, Primary, Gearbox => Topic started by: tlmark on 06.11. 2016 10:48

Title: pleasent suprise
Post by: tlmark on 06.11. 2016 10:48
The first winter job on my new SR has been to fix (or at least try) the oil leak from the primary cover.
So on pulling the cover off I was pleased to find it has been fitted with a SRM clutch. *smile* it didn't look like there had been any kind
of sealant other than the gasket so I used a bead of 3 bond either side of the new gasket so fingers crossed.
24hrs later and no leak so far (but the motor hasn't run so I'll not get too excited).

I did notice that the cover has had the old clutch nut and output shaft nut has had a good go at wearing through at some point in its life  *eek*
Title: Re: pleasent suprise
Post by: Greybeard on 06.11. 2016 10:56
I don't have a problem with leakage from that case. At the moment I only have Hylomar on one side of the gasket which makes life easier when removing the cover. I did take some care when rebuilding the engine that the mating surfaces were all flat, (smooth file applied across opposite edges). I also used standard slotted screws tightened with a screwdriver rather than Allen screws which I believe can be overtightened and distort the case.
Title: Re: pleasent suprise
Post by: tlmark on 06.11. 2016 11:02
Yes all my screws are all allen screws  :!
Title: Re: pleasent suprise
Post by: Greybeard on 06.11. 2016 11:23
Yes all my screws are all allen screws  :!
Overtightened Allen screws can pull up the metal around the screw hole so that's something you can investigate.
Title: Re: pleasent suprise
Post by: a10gf on 06.11. 2016 13:41
Quote
So on pulling the cover off I was pleased to find it has been fitted with a SRM clutch
...usually when pulling some cover one rather finds old catastrophies :O)
Looks like an excellent clutch, working good?
Title: Re: pleasent suprise
Post by: tlmark on 06.11. 2016 17:03
Quote
So on pulling the cover off I was pleased to find it has been fitted with a SRM clutch
...usually when pulling some cover one rather finds old catastrophies :O)
Looks like an excellent clutch, working good?

I can't compare it to a stock clutch, as this is the only BSA I've had. But yes once i got it set right I've had no problems.
Title: Re: pleasent suprise
Post by: BSA_54A10 on 07.11. 2016 10:50
Put some thick washers behind those allen bolts the smaller area under the head makes a mess of the holes.
Next time you pull the cover off, 3 bond between the gasket & the cover and bentonite grease ( wheel bearing ) between the gasket & the engine.
That way the gasket will always strip ff clean and stay with the cover.
Title: Re: pleasent suprise
Post by: RichardL on 07.11. 2016 13:28
Trevor,

Do you have a source for those washers? They turn out to be a very small O.D. with respect to I.D. and thickness, so are not any common size I've been able to locate.

Richard L.
Title: Re: pleasent suprise
Post by: ellis on 07.11. 2016 20:17
 Hi tlmark,
      As you say the SRM clutch is a nice piece of kit. Before you replace the cover I would get those springs set correctly. You should only have about one turn of the spring showing, And if you have one check it with a DTI gauge to make sure it releases squarely. Once set correctly one finger should be enough to pull the handle bar clutch lever in.    *smiley4* 

  ELLIS
       
Title: Re: pleasent suprise
Post by: olev on 08.11. 2016 02:34
Hi Richard,
I'm not sure where Trev gets his washers from but I resize them by slipping a dozen washers on a bolt, tighten them up with a nut and turn the lot down on a lathe. Very quick, accurate and easy.
cheers
Title: Re: pleasent suprise
Post by: RichardL on 08.11. 2016 03:48
Without a lathe, I've done it similarly using a grinder (letting the washers spin on the bolt) but gave it up for being too much hassle a few cover removals ago.

Richard L.
Title: Re: pleasent suprise
Post by: worntorn on 08.11. 2016 06:30
I believe the type of washer you are looking for is called an AN washer. They are a close fit on the bolt and have a fairly small OD/to ID ratio.
Available is SS or plated regular steel.

Glen
Title: Re: pleasent suprise
Post by: BSA_54A10 on 08.11. 2016 09:27
Trevor,

Do you have a source for those washers? They turn out to be a very small O.D. with respect to I.D. and thickness, so are not any common size I've been able to locate.

Richard L.

Must be from the shop next to Olev's
Used to be able to get them from one of the hand made stainless bolt merchants, but he gave it up a while ago so it is on a bolt into the drill press chuck and out with the file.
I had some high tensile ones that were double thickness but now I double up after running an end mill down the hole to square off the bottom of the head hole.
Title: Re: pleasent suprise
Post by: tlmark on 09.11. 2016 11:51
Hi tlmark,
      As you say the SRM clutch is a nice piece of kit. Before you replace the cover I would get those springs set correctly. You should only have about one turn of the spring showing, And if you have one check it with a DTI gauge to make sure it releases squarely. Once set correctly one finger should be enough to pull the handle bar clutch lever in.    *smiley4* 

  ELLIS
     

Bugger I have already put it back on  :!

I didn't even look it because it had been no trouble