Ariel telefork oil seal holders

[Roderick.Bradley]

Can pre-1968 BSA fork seal holders be fitted in place of Ariel ones?

For information, I have measured up front fork oilseal holders from a 1959 Ariel VH & an 1955 Ariel KH. I have owned both bikes for 40 plus years so I know that these seal holders the same ones originally fitted when the bikes left the factory. The seal holders from both bikes are of the same dimensions. They are 106mm or 4 & 5/32 inches long. The depth of the recess at the threaded end is 7/8 inches (minus the oilseal in place). The depth of the oil seal is approx. 3/8 inches leaving 1/2 inch of thread clear when the seal is fitted. The little, projecting ledge that retains the seal is approx. 0.125 inches deep. The depth of the recess on the side within which the spring is located is 3 & 5/32 inches. The bore of the threaded section is approx. 1 & 15/16 inches.

I don't have any pre-1968 BSA fork oil seal holders to measure in comparision but I wish I did. Dies anyone know if they can be substituted? Photographs indicate that the flare at the top end of the holder is much more pronounced on the currently available BSA part than on the (original) Ariel part which might or might not be a problem?
Rod

[pete.collings]

I think you can use BSA fork oil seal holders on Ariels, but they are a different height, although the bottom section that theads into the sliders is essentially the same. You need to consider what fork springs you use, getting a mismatch of spring and holder can result in a gap appearing when the forks are at full extension, or could risk the top of the oil seal holder hitting the bottom yoke/shroud base. Ariel springs were generally shorter but a higher poundage rating than BSA springs, having said that I have used a set of BSA springs in a Huntmaster that nearly left a gap, but soon settled down to an acceptable fit into the fork shrouds, although whether this happens with the lighter singles I am not too sure. I think BSA used shorter shouds and longer oil seal holders, but do not have anything to measure to confirm this.
The flairs at the top are non critical (and often will adjust to the inside diameter of the shroud), I presume they are to lessen any rain/moisture getting inside the oil seal holder, and prevent spring grease getting out.

If anyone can provide more detailed experience of intermixing Ariel and BSA fork parts, that would be useful to know.

[andrew.chapman]

I have bikes with both types of forks at home. Sadly, I am not at home, otherwise I could measure the diameters of the respective shrouds. If you don't have the answer by Thursday evening, when I will be back at home, I will measure up and let you know.

I doubt that the seal holders are likely to hit the lower yoke. That would be a lot of travel.

[Roderick.Bradley]

There are BSA stainless oil seal holders on sale on Ebay which match the dimensions I've measured for Ariel except for total length. These BSA ones are reported to be 4 & 7/8 inches long, i.e. 23/32 inches longer or in rounder figures approx. 3/4 inch. Can you see that making a difference, Pete?

Rod

[pete.collings]

I'll dig out a few old parts and check dimensions, and get back to you (Rod) in a few days time

[keith.mettam]

Hi Roderick,
I've been reading this post with interest and am wondering why you are interested in fitting BSA fork oil seal holders to your Ariel. DraganFlys have chrome Ariel ones in stock at present and also sell the stainless steel ones, unfortunately these are out of stock at the moment. Maybe this why you are sourcing stainless steel BSA ones ?
All the best,
Keith.

[Roderick.Bradley]

You're right, Keith. I don't like using chrome holders bacause they rust & I really hate dismantling & rebuilding front forks to replace them. I've done enough of them to know I don't like it. I did, indeed, try Drags in vain for stainless ones and you just don't know how long you have to wait for something that's out of stock there. For example, I waited about a year on a backorder for a rear wheel sprocket until a letter arrived advising that their previous supplier no longer wanted to make this part & my order was,therefore cancelled. I don't blame Drags because this how things are for them. However, I found the correct sprocket elsewhere within 2 weeks which I could have done, I suppose, had I tried a year earlier.
I am running out of time with this bike as I had planned to get it up & running by this summer and still hope to do so. It hasn't turned a wheel since I rode it home after buying it in the winter of 1970. Far too long so I've got to get on with it.
Rod

[keith.mettam]

Rod, have you tried John Budgen yet ? He lists the stainless steel oil seal holders........might just have a pair in stock if you're lucky !

http://www.johnbudgenmotorcycles.co.uk/girder_forks.htm

Regards,
Keith.

[Roderick.Bradley]

I did try Budgeon a few weeks ago but he was out of stock & had no idea when he might have ones in again.
Rod

[andrew.chapman]

The external circumference of the fork shrouds is exactly the same on the Ariel forks and the BSA forks. It's 18cms.

You can get stainless steel seal holders for the BSA forks from Stewart Engineering. They are actually sold for a Sunbeam S8 but they are identical.