Hi guys.
I pulled the gear from the magdyno pinion today to replace the oil seal (Part no’s 65-2316). Expecting to see a D:38mm recess to press the seal into. Instead I found this? Approximately a 22mm recess.
What does anyone think? Is the seal compressed against the inside face of the timing housing or should it fit into a recess.

The deeper seal is the replacement.

email (option): hampshire66@gmail.com

David Hampshire

Hi guys.
I pulled the gear from the magdyno pinion today to replace the oil seal (Part no’s 65-2316). Expecting to see a D:38mm recess to press the seal into. Instead I found this? Approximately a 22mm recess.
What does anyone think? Is the seal compressed against the inside face of the timing housing or should it fit into a recess.

The deeper seal is the replacement.

email (option): hampshire66@gmail.com

It does look a bit deep! Dragafly's image looks slimmer https://www.draganfly.co.uk/index.php/component/hikashop/product/12522-
Click to zoom in!

Or contact Darren Wrudd from this forum who can probably also supply you.

BTW you've displayed it the wrong way round on your pinion. Ron

email (option): ronpier@talk21.com

Thanks Ron.
That’s just as it came off the bike so could be why it was leaking oil.
Does the seal press into a recess or simple sit in the shaft butted up to the inside of the housing when you tighten the nut?

email (option): hampshire66@gmail.com

The seal should be a press fit in the recess in the timing cover with the spring side facing you. If it's a loose fit it's liable to turn with the pinion and wear the recess even more. A mediocre fit can probably be overcome with some sort of glue or loctite retaining fluid. Otherwise a more radical repair of the area might be required, which could mean a partial or full strip of the engine. Ron

email (option): ronpier@talk21.com

Thanks Ron

email (option): hampshire66@gmail.com

Hi David,
Drop mean email if you can and I will sort you a suitable seal.
Cheers.
Darren

email (option): d.wrudd at sky.com

I have the same problem with the seal, it falls out of the casing.I ordered a seal from Draganfly which is not as deep as the one shown , but the outside Dia is too small due to, as been suggested could have been spinning around in the recess for a while , funnily enough my seal was in back to front when I took it apart and there was oil under the magneto .

I've measured the seal from Draganfly which fits apart from the OD. I used metric measurements as they were the closest I could find on the net to the sizes I need which is 20x40x7mm SC / R21 Single Lip Viton Rubber Metric Rotary Shaft Oil Seal with Garter Spring .

The measurements of the seal from draganfly 20.7mm shaft , 38.2mm OD 5.87mm depth so the 40mmm Viton seal will hopefully make up for the wear in the casing and be a tight fit........Fingers crossed .

Dave

One of the rare cases when silicon is allowed to be used.
Glue it into the case.

email (option): bsansw1@tpg.com.au

I was going to try the "oversized" seal first ,if that's not successful try find an engineer that might be able to sleeve it, then revert to "glueing" it in place with instant gasket or Sika as a last resort . Hopefully the seal will do the trick .

I used to get a lot of hassle with these in my old shop,my halls refrence book on oil seals on which i ordered them quotes all bsa singles 1949-63 no bsa part number in brackets but (conversion) seal B338 size 20.6x38.18x4.7 the most seals i had taken out of these engines were just like a rubber bung with a hole in the middle made out of what looked like rubber impregnated with string

email (option): malmotorcycles@gmail.com

['the most seals i had taken out of these engines were just like a rubber bung with a hole in the middle made out of what looked like rubber impregnated with string..']

That's the original BSA seals...They were made from a rubber/cloth composite and pre dated the modern oil seals we are all more familiar with...Ian

email (option): ian@wright52.plus.com

email (option): bsansw1@tpg.com.au