Hello All

Working on a set of forks for my Model 10 project and have a couple. of questions which I hope all of you with more Bultaco knowledge than me can answer.

On stripping down the forks I have found that the damper components have suffered from corrosion as can be seen in top photo, so does any body know if these valves are available ? if not looks like a job for my lathe and milling machine.

Second question is how does the bottom aluminum fitting come off the damper rod is it threaded or press fit any advice before I start as I want to limit damage.

I would ask about specific parts IF they are still available together with your frame and engine number.

 

In my experience most small parts are if not you might too look up for used forks. For the UK BultacoUK / InMotion.

Not available  are these plastic rings around the piston that tighten it to the inner stanchion.

 

As you have obviously a lathe at your hand you can refabricate many parts.

 

That aluminium part with the taper on it is a hand-slip-on fit on the damper rod when there is no corrosion. This part is the anti-bottoming cone.

On later models like 199b even Made out of plastic. Anyway beside the sliders of the piston there is very little that has to be replaced in my experience. Most prune for repair or replacement are the stanchions und the power fork legs. The stanchions are often bent and the inner bore of the power legs shows often much wear.

If the lower fork legs are worn out my personal fix is to let the inner bore be rebored mostly 0,2mm more in diameter and then too a straightening and alignment and re- hardchrome of the upper steel stanchions adding 0,10mm to the hardchrome layer thickness, that is the easiest was to get a proper as new working fork pair.

It's a pity that the Betor forks don't have separate sliders for the lower fork tubes.

 

Seeing the corrosion damage on the one-way valve in your photo, I suggest you also have a good look inside the tubes where the damper piston runs. The swept area in the tubes may have corrosion damage that will affect the damping performance even it you make or buy replacement damper pistons