The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: starfield on 15.02. 2011 14:16

Title: A7 Star Twin Forks
Post by: starfield on 15.02. 2011 14:16

Having sorted the mag problem and the rear wheel bearings, with help from this forum, I am about to embark on the front forks. Part of the reason is cosmetic, the seal holders are looking sad and they drag the whole bike down so  set of s/s items is on the shopping list. Can anyone recommend a particular supplier as I am a bit wary of pattern parts. Pricewise they all seem to be around £80 with seals.

Second reason is mechanical. The fork action is heavy, a bit clonky and you can hear the spring on one side rubbing inside the shroud. I get the feeling that the fork springs have either been packed out or are too strong, possibly sidecar type. Can anyone advise me on the correct number of turns and wire diameter for solo A7 springs. Any other advice on what to look for welcome. I have just stripped a set of Ariel teles for a friend and they look very similar to the A7 forks so I am hoping the knowledge gained on these will help. Thankfully another friend has the tool for drawing the stanchion into the yoke.

thanks

Peter

 

Title: Re: A7 Star Twin Forks
Post by: chaterlea25 on 15.02. 2011 20:57

Hi Peter,
I'm sure there are probably other "good" suppliers but
I bought a set from Barleycorn Engineering, They are first class

http://www.barleycorn.co.uk/

HTH
John O R

Title: Re: A7 Star Twin Forks
Post by: trevinoz on 15.02. 2011 22:04

Peter,
          Springs are 10 3/4 " long, 20 1/2 turns and wire is approx. 0.210"
Trev.

Title: Re: A7 Star Twin Forks
Post by: Jules on 27.05. 2011 09:38

Hello Trev., are these springs the same as standard A10? I need to replace mine, can you get them locally in Aus...? cheers

Title: Re: A7 Star Twin Forks
Post by: trevinoz on 28.05. 2011 23:30

Jules,
            That is standard.
I don't know whether you can get them in Australia.
A few of us BSA idiots got together some years ago and had a batch made locally but stupidly only got enough for our own use.
They are available from British Spares in NZ at around A$30 each. Progressive are more expensive.
 Trev.

Title: Re: A7 Star Twin Forks
Post by: Jules on 29.05. 2011 09:55

thanks Trev., I'll give them a go, your thoughts are much appreciated (still too early for Karma, I need 25 posts apparently to "qualify"), cheers

Title: Re: A7 Star Twin Forks
Post by: alanp on 29.05. 2011 11:19

Watch it! Don't be tempted to extract or install the fork seal units by clamping and twisting the outsides. You risk squashing damage. Get a proper tool from say Lyford Classics which drive the units on the inside lugs, they are not expensive and you know it makes sense. Also put some decent sealant on the threads on assembly. BSA used to use some thin string on the threads but times have moved on.
I've used Barleycorn seal units and they are 1st class and stainless.
However, judging by the date of the original post you are beyond that point by now.
Alan