What have you done with your bike/s today?

[Colsbeeza]

Thanks Swarfy, Points pivot is new and OK, spring strong. I have checked the primary and secondary resistance of the coil. Purchased another new one with exactly the same values. BTW it is a dual coil for wasted spark: It fires on both cylinders at same time for both compression and exhaust strokes. Capacitor and spares all passed the Ohms and Voltage test, but doesn't say anything about the performance when in the cylinder - hence a Megger for a proper capacitor high voltage test and spark tester for under load. Hopefully that should point to the problem.
Cheers Col

[Catz]

Today,for the God-knows-how-many-time i've taken the front end apart on my A10 to fix the leaking fork seals.
What is it with these forks? I've had new fork tubes, new seal holders, new seals and still it leaks. Wrapped the threads with string and PTFE tape. What's the trick lads?
I even purposefully put less oil in last time i did it to counteract the leaks but still it happened. No wonder the Japanese beat the Brits at our own game. LOSING MY PATIENCE WITH IT NOW! And yes, i meant to shout.

[berger]

Catz maybe you've answered the question yourself , where are all these new parts made, certainly not at the bsa factory's. to stop a slightly pitted fork leg weeping on urma yonda i found a seal 1mm smaller id and it worked , bearing supplies have all sorts of seals that could fit, on the yonda i couldn't find one the same thickness but made up a spacer to compensate.

[Catz]

Thanks for the tip mate. I even thought about running the forks with no oil.  Grease might be better

[Worty]

Today,for the God-knows-how-many-time i've taken the front end apart on my A10 to fix the leaking fork seals.
What is it with these forks? I've had new fork tubes, new seal holders, new seals and still it leaks. Wrapped the threads with string and PTFE tape. What's the trick lads?
I even purposefully put less oil in last time i did it to counteract the leaks but still it happened. No wonder the Japanese beat the Brits at our own game. LOSING MY PATIENCE WITH IT NOW! And yes, i meant to shout.

I don't think I've ever replaced the r/h seal, but the l/h has been replaced at least four times and leaks almost immediately it's 'fixed'.  Why is it that one seal is perfect and the other a complete and utter b*****d.

Incidentally, what are the dimensions of the standard seal??

[berger]

worty i have 1/7/8ths x 1/3/16 x 3/8  but maybe cats will need a metric seal to get some squeeze on the leg .

[RDfella]

Had a leak-prone fork leg myself. Trouble, If I remember correctly, was the S/S seal holder not clamping the seal properly. Also, some seals are metal cased - one needs the all-rubber type. Again, if I now recall correctly, I needed a spacer to ensure the seal holder was clamping the seal properly.

[Worty]

Had a leak-prone fork leg myself. Trouble, If I remember correctly, was the S/S seal holder not clamping the seal properly. Also, some seals are metal cased - one needs the all-rubber type. Again, if I now recall correctly, I needed a spacer to ensure the seal holder was clamping the seal properly.

Mine are/were metal cased, where do you get the all rubber type?  Does this mean that if you get the all rubber type, you need the spacer??  I'm also guessing Bergs modification is all rubber?

[berger]

yes worty but if you are  good at coating the steel backed ones with a coat of goo it will do, bars open

[chaterlea25]

Hi All,
I have come across at least one fork slider where it leaked around the joint of the threaded part and tube

I came across someone who forced the seals down from the top of the fork stanchion, no wonder it leaked

I have found that the rubber seals with a secondary lip on top face help keep the water from getting sucked into the innards

John

[Catz]

Thanks for all the replies. Looks like it's a common thing onthe bike. I'm going to try a few of the remedies including one or two of my own.

[Worty]

Let us know Catz.  I'd be happy to try anything that works on the l/h leg

[Swarfcut]

 RD mentioned a lack of clamping to keep the seal in place, the original design relies on a tight (and oil tight fit) of the seal in the holder.

  A65 forks use a collapsible pressed steel spacer to hold the top fork bush in place in the slider, so no pesky wire snap ring, and the spacer also retains the seal in its holder. This has already been a topic well documented on the Forum and is a simple swap, it all fits.

 As to leaks, oil above the seal should not be able to appear between the holder and the slider.... The "turn of twine" etc is supposed to stop that. So a leak here is below the seal and is down to poor fit and sealing on those fine threads, not a failed oil seal.
  A failed seal will allow oil to fill the holder and overflow down the outside. Is that what you have?

 I suppose an unblemished leg, close fitting bushes, a supple well supported correctly sized seal and a bucket load of hope should do it. Grease is a no no. The damping action relies on oil being  forced through a small hole.

 The other way is to consider it as a rust prevention solution and just refill when the leak stops.......
 Worth looking at bearing suppliers for a source of seals that will do a better job, I'm thinking multi lip or wiper types used on hydraulic rams. Also treat seals with care, assemble by passing the lubricated seal in its holder up the leg and check the lip tensioning spring has not been displaced.

 Swarfy.

[Catz]

  A failed seal will allow oil to fill the holder and overflow down the outside. Is that what you have?

 Grease is a no no. The damping action relies on oil being  forced through a small hole.

 Swarfy.

Yes, that sounds about right.

I was joking about using grease.

[Billybream]

I had a leak off one fork leg, just a drop appearing on the front wheel when standing, refurbished the forks complete, used the A65 pressed steel spacer to get rid of the cirlip, but bugger still a leak, finally discovered a pin hole through failed weld or brazing of the lug to the bottom of the leg, another gremlin of these old girls.