Vintage Motorcycle Eccentrics

I just traded my 1974 OSSA Explorer for a 75 Super Pioneer.
I always wanted one of those and since I really was not using the Explorer, I figured I would trade it for something else I probably won’t use much . Ha

I only rode it around the yard so far, much ‘peppier’ than the Explorer- which makes sense because it was a trials bike with larger tank/seat. Felt nice, good position. I think I will ride it on stuff I take my Xtrainer on when I’m in the mood. Not all of it, the clutch is a LOT stiffer than the super light one (with Clake2) on the Beta. I could fit a hydraulic clutch setup and use a ‘One Light clutch’ - but I probably won’t go to that much trouble. (Especially since I gave away the magura slave I had).

This one didn’t have a title, and now the ‘Owership in Doubt’ is a huge hassle. Only place that inspects them is Tacoma and I looked out 2 years and didn’t see an appointment available… I’m going to see if there is any alternative.

Another.
My ‘MityVac’ compression tester claimed 210 psi. I think it is optimistic, but I use the same one for trending pressures more than anything.
That said, that is right in the ‘new’ range of other modern 2-strokes for this meter.

These engines have very simple piston port (two transfers and exhaust) but were well know for superb power delivery.
Wish I could still get Curnutt shocks- those really worked great. Maybe some Works ones…

Nice looking little bike. May be easier to get a Vermont title then transfer back to Wa.

I had been checking 2-4 times a day, finally found a cancellation for two days later. I went a couple of weeks ago (Vancouver), got the inspection done. Now i have a plate and clock for three years has started.
Just had to keep checking!

Nice first ride awhile back

Nice going! It looks like a blast to ride. I should be doing the title thing on some of my bikes but what a PIA.
Starting on the Shadow finally. Another year or two project. I want to enjoy it because it will likely be my
last major project.

I added an updated spark arrestor on the OSSA.
Since it stuck out (the diameter) a bit I wanted to make something that would ‘smooth it out’ a bit and also a secondary retainer.
I’ve never done a taper before, but it came out fairly well and I managed to guess just about right for the angle. Heck- I even got the tapped screw hole on the bottom lined up right.

The inside is straight- snug fit over the short ‘tail’ of the stock muffler.

Oh yeah- it took me a ridiculous amount of time. It started as a solid rod and I have a pretty darn small lathe…

Looks nice. Are you replacing the original spark arrestor? Does this piece go inside the pipe?

Originally from the factory- there was no spark arrestor. Someone had added one some time ago, but it was getting pretty tired.
So I bought this one.
It does go in aways- a ‘screen type’ which I don’t like as much. But they are effective and legal. Just have to clean them out and keep an eye on them.

Original pipe has a ‘tail’ that comes out about as far as this aluminum taper piece.
This picture shows the new arrestor before I made the tapered piece. I didn’t like out it stuck out, giving something to catch on.

I scored a set of 5” travel Curnutt shocks. I used these back in the 70s, way, way better than anything else I tried. They were quite different with a floating compression valve and longer travel than most (especially in the 60s).
They appear to be just the right length and travel for adding some travel to the rear of the OSSA- should go well with the longer travel Betors I have from a GPIII.

I made a couple of bushings for the bottom (have to make 4 altogether). The are aluminum with an O-ring to rotate on. Nicer than the rubber gizmos most used back then.
some of these were nitrogren charged, although no fitting. Apparently, after bleeding and putting into boiling water to set fluid level etc- a special fitting was put on with an O-ring on the seal head and another on the body. Then the sealhead could be loosened a little and the charge put in that way. I guess.

There is a guy that worked for Charles Curnutt (sr) back in the early 70-80s. He still rebuilds them and has the special fitting. Pretty cheap too. All the seals/O-rings were standard sizes, but I may just have him do these since I’m not even sure if they take nitrogren or not. Once I find that out maybe next time I’ll do it.