BSA Owners' Club Forum

The BSA Workshop => Twins => Topic started by: pockets on 18 May, 2022, 19:53:28

Title: A65 Primary chaincase
Post by: pockets on 18 May, 2022, 19:53:28
Have to replace gasket on chaincase no wonder it leaks , is this  normal to have so   small an amount of mating surface on the bottom part of gasket seam where i presume the oil drain allen bolt sits .
Title: Re: A65 Primary chaincase
Post by: pockets on 18 May, 2022, 20:11:06
https://flic.kr/p/2nmr2RP
Title: Re: A65 Primary chaincase
Post by: DAVE BRADY on 18 May, 2022, 20:16:01
Hi Pockets,

Quite normal on those cases.  Use a good quality gasket and it should not leak.

Dave.
Title: Re: A65 Primary chaincase
Post by: pockets on 18 May, 2022, 20:24:26
Got one from srm along with some rtv  silicone sealent , they dont stock Wellseal  any more something to do with being toxic or somesuch . any tips on using the granville sealent . gunna use some alchohol to clean the surfaces , can see why old brithish bikes have a habit of leaking oil going on the design of the drain plug on the chaincase , shaving away the material in that locationto aid oil outlet  isnt the best idea. Can people open the image from the flickr  link i supplied?
Title: Re: A65 Primary chaincase
Post by: DAVE BRADY on 18 May, 2022, 20:51:30
Hi,

Yes, I opened the image Ok but you can post on the Forum if the images are not too big.
I use Hylomar on the case only and 'stick' the gasket to it then leave it for a few minutes to settle (it does not set hard).  Coat the other surface of the gasket with plenty grease. I use a high temp. moly grease.  It may look like it soaks in so apply a bit more if needed.  The idea of the grease is that you can take the case off and the gasket remains intact to be used several times.  Just smear on a bit more grease each time.
Also, do not over tighten the screws.

Dave.
Title: Re: A65 Primary chaincase
Post by: cdsdorset on 18 May, 2022, 21:09:29
Forget the gasket  just use 3 bond.
Title: Re: A65 Primary chaincase
Post by: pockets on 18 May, 2022, 21:10:35
thanks Dave  , may give the grease a go just dont want it to leak again , the gasket is green one side and blue the other , wondering which way to put it, but may find it only fits one way . the  allen bolts seem quite short on some of the threads and a little loose in the thread ,  a few of them are a different allan key size  {slightly smaller} ,  not sure what's going on there , may check that they are gunna be ok before proceeding .
Title: Re: A65 Primary chaincase
Post by: pockets on 18 May, 2022, 21:13:03
Have purchased the gasket and sealer  already  so going to use it.
Title: Re: A65 Primary chaincase
Post by: spaceman on 19 May, 2022, 06:30:49
thanks Dave  , may give the grease a go just dont want it to leak again , the gasket is green one side and blue the other , wondering which way to put it, but may find it only fits one way . the  allen bolts seem quite short on some of the threads and a little loose in the thread ,  a few of them are a different allan key size  {slightly smaller} ,  not sure what's going on there , may check that they are gunna be ok before proceeding .
I would definitely check the length of the screws against the parts book to make sure you have got the correct lengths and to also check you are using the right screw for each hole by dry fitting the cover and checking the depth to the bottom of the threaded hole. If you use the wrong screw, it is very easy to strip the thread.
Title: Re: A65 Primary chaincase
Post by: DAVE BRADY on 19 May, 2022, 07:30:56
Hi,

Ditto what Spaceman said about the screws.  Some of the replacement 'Allen' type sets are not all of the correct length and some have a poor quality thread.  It is worth having a good poke in to the holes as years of gunge and bits of sealant build up at the bottom.  Some brake cleaner and an air line are a great help.  For persistent crud a tap can be run down the thread to get it nice and clean  You may find another 1/4" of thread is available and the true depth of the holes can be used.  The more thread that is engaged the more secure the screw.  When tightening with an Allen key only use the key (standard length) itself as no extra leverage is necessary.
The screws that are bit loose and need a smaller Allen key are a bit suspect. 

Dave.
Title: Re: A65 Primary chaincase
Post by: cdsdorset on 19 May, 2022, 09:00:45
To make sure the bottomoc the hole is clear of gasket goo wind a woodscrew around in it.
Title: Re: A65 Primary chaincase
Post by: pockets on 19 May, 2022, 10:37:50
Thanks for the tips , ye was gunna closer inspect all the bolts before reusing by seing how far they all protude throught the cover , anybody now the correct lenghts and size /pitch and good  supplier , the ones with it may just be bad  aftermarket stainless replacements.
Title: Re: A65 Primary chaincase
Post by: pockets on 19 May, 2022, 10:59:52
Downloaded a parts catalogue but the part number doesn't come up with a search, and dimensions aern't shown so not a lot of info to be gleened.
Title: Re: A65 Primary chaincase
Post by: chaz on 19 May, 2022, 12:55:51
pick the year of the bike from the options
https://draganfly.co.uk/product-category/bsa/sparesparts-for-bsa-a50-a65/

they usually have threads and lengths listed otherwise search places like
https://www.baxtercycle.com/parts/parts-books-online/bsa/and use their search facility

eg for 1966 get the part number, there are a few different lengths, then go onto their shop page and enter.

https://www.baxtercycle.com/product/76-0546/
https://www.baxtercycle.com/product/70-8168/   note on this part number, they give 2 or 3 optional numbers
Title: Re: A65 Primary chaincase
Post by: spaceman on 19 May, 2022, 14:06:00
What year is the A65?
Title: Re: A65 Primary chaincase
Post by: spaceman on 19 May, 2022, 15:18:29
I can see it is from 1964.

The chaincase covers uses 1/4" BSC screws as follows, as far as I can determine:  4 x 1 11/16" screws, 6 x 1 1/2" screws, 1 x 1 1/2" drain screw and 1 x 11/16" oil level screw - making a total of 12

It would be worth checking the length of each tapped hole with the cover in place to double check these lengths and to work out which screw goes in which hole.
Title: Re: A65 Primary chaincase
Post by: pockets on 19 May, 2022, 19:36:45
Thanks for reply , I've gone with reusing the  bolts, some were a little short but I shuffled them about and used the longer ones at the bottom of the join , seemed to go together snugly with the new gasket and some sealent used sparingly . gunna leave it 24hrs to cure before putting the  oil in. Have a feeling it was leaking from the fibre washers on the drain and fill screws so put  a little ptfe on the bolt head. now found that one of the oil lines has split on the outlet pipe of oil tank , another bad quality item the rubber just doesnt last , have the same issue with crap replacement  parts on my old veedub splitty. Also the way the lines run around the trailing arm pivot seems like a weird place to put them as they are suseptable to wearing through  on the pivot arm. I'll make them longer but still seem an odd place to run them without a bracket to hold them away from the pivot.
Title: Re: A65 Primary chaincase
Post by: pockets on 19 May, 2022, 19:45:04
(https://live.staticflickr.com/65535/52083924997_6730b6ca33_z.jpg) (https://flic.kr/p/2nmtJjR) (https://flic.kr/p/2nmtJjR)
Title: Re: A65 Primary chaincase
Post by: pockets on 19 May, 2022, 19:53:25
A snap of the bike (https://live.staticflickr.com/65535/52085001903_cd8a37ab2f_z.jpg) (https://flic.kr/p/2nmzfsc) (https://flic.kr/p/2nmzfsc)
Title: Re: A65 Primary chaincase
Post by: spaceman on 20 May, 2022, 09:23:09
Thanks for reply , I've gone with reusing the  bolts, some were a little short but I shuffled them about and used the longer ones at the bottom of the join , seemed to go together snugly with the new gasket and some sealent used sparingly . gunna leave it 24hrs to cure before putting the  oil in. Have a feeling it was leaking from the fibre washers on the drain and fill screws so put  a little ptfe on the bolt head. now found that one of the oil lines has split on the outlet pipe of oil tank , another bad quality item the rubber just doesnt last , have the same issue with crap replacement  parts on my old veedub splitty. Also the way the lines run around the trailing arm pivot seems like a weird place to put them as they are suseptable to wearing through  on the pivot arm. I'll make them longer but still seem an odd place to run them without a bracket to hold them away from the pivot.

The OEM oil pipes were steel braided which would have protected them from chaffing against the swinging arm. On my A65, the pipes are long enough to loop up clear of the swinging arm and therefore there's no danger of them being damaged.
Title: Re: A65 Primary chaincase
Post by: pockets on 20 May, 2022, 10:46:33
Thanks spaceman , yes I'll  make them longer , just seems a bit of  a strange route without a bracket  and they also seem to crossover , but as you say the  steel braiding wouldv'e helped . All the suppliers Iv'e seen  seem only to  stock  the cotton braided type .
Title: Re: A65 Primary chaincase
Post by: spaceman on 20 May, 2022, 13:53:03
The earlier A10 used armoured oil pipes because they were routed under the moveable, pre-unit gearbox and these are still available. However, there was probably never a real need for even steel braided oil pipes on the A65 and so they are not normally sold in this form. 
Title: Re: A65 Primary chaincase
Post by: pockets on 20 May, 2022, 19:45:36
Thanks for the info , have renewed them with fresh braided hoses and the correct pipe clamps rather than jubilee clips , also zip tied them to the frame to keep them clear of the  pivot . Have tried to fire it up  after priming the cylinder with a squirt of fuel  down plug hole, it fired up and responded to throttle briefly before  puttering out , maybe just cold or maybe need to have a look at the carb again . Will have another crack tomoz , should get it going hopefully , result.