James> Skip referenced the need for a late style, but then calls the cup
James> design the late style... the LATE model shuttle i believe is in
James> fact the one that skip has. (the one show on the top in the
James> photo referenced below). So did skip mean to say he needs an
James> EARLY shuttle?
James,
I think I just worded things badly. The picture I referenced shows two
shuttles, an early version with cup seals, and a later version with o-rings.
Not knowing any better, I assumed there were only two styles of shuttles. I
bought a PDWA from (purportedly) a '72 or '73. The text from Nelson's MC
rebuild article on the Buckeye Triumphs site says, in part:
I have PDWAs from years '68,'70, '73 & '76 and all have 5/16"
cylinders. Three use O-Ring seals as the lower piston in the
photo and one uses the more substantial seal as the upper piston
in the photo.
Knowing that I had a '68 PDWA with cup seals, I assumed that at least from
'70 onwards o-ring style shuttles were used. I incorrectly assumed the one
I was buying would have an o-ring shuttle. It had a cup seal shuttle, but
it was slightly different in cross section in the center switch activation
region than the shuttle from my TR-250. I then inferred (perhaps also
incorrectly) that what I purchased was what I think of as a "late" cup seal
PDWA.
It's not obvious to me that you couldn't use o-rings on the cup seal style
shuttle, but you'd have to find o-rings with much smaller inside diameters
than the TRF rebuild kit provides. The pressure bears from the ends of the
shuttle which would tend to press the o-rings up against the inner shoulder.
You might have to place two o-rings on each side. Has anyone tried this
successfully?
Moral of the story: Don't buy a pig in a poke like I did. Check the shuttle
before buying...
Skip
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