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M159 Forks

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I've stripped my M159 forks down and they have upside-down U-shaped spacers at the bottom of the springs, these spacers do not appear in either my Haynes or Clymer manuals. They are shaped like a capital U with a flare at the ends. Are they required or are they a mod' that has been completed by a previous owner in an attempt to pre-load the spring? Any ideas?

I've got new springs, newly re-chromed stanchions (Philpotts in Luton) and new fork seals, so I'm not expecting them to have anything other than a "standard" feel initially, I can mess with the oil weight etc later. The general condition of the internals appears to be fine with no obviously excessive wear that might demand additonal spacers.

Thanks

Mick

Yes, they are a standard fitment to Betor forks fitted to Bultacos and Ossas

They aren't thick enough to have any affect on spring tension. I can only guess that they prevent the oil squirting geyser-like, straight up the forks tube, from the top of the damper rod when the forks are compressed. For what purpose I don't know, maybe to help slow the oil flow and help compression damping?

So yes, they do belong in there, but in my experience, there is no difference to the damping or fork action on either a Bultaco or Ossa if they are fitted or not.

They do two things, they are in effect "baffles" and... help seat the spring onto the damper tube.

as an aside, I took the liberty of making up two types of tool for Bultaco forks, one which fits the up to 199A type Betors and the other which fits the 199B type fork with a small but important modification to the damper tube.

It enables me to tighten fully the allen bolt on the end of the damper tube nice and tight (not over tight) without relying on the spring to do the job fully assembled.

Big John

  • Author

Thanks for your help, I'll re-fit them if they are standard. Cheers

Mick

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