Not according to Nelson. He says the 73 has the earlier cables, but maybe he's
wrong. Sounds like he
thinks the later solid cables (really late cold start valves) are crap, and
regardless of why you
have them, maybe you should get rid of them, so you can use the earlier
stranded cables (and cold
start valves).
I love reading his stuff..... "Moral of the story --- dont try to push a
wire." ... LOL
He says....
Modifying Late Cold Start Valves
The TR250 and TR6s through 73 use a flexible choke cable. These cold start
valves have springs
that return the valve to the off position when the cable is slackened by
pushing the choke knob in.
The later cold start valves dont have a spring. In fact, there is a
spring-loaded ball that rubs
against the cam on the valve that tends to restrict movement. There is a
detent is the cam that the
ball fits that tends to lock the choke in the partial on position. The choke
cable is a stiff wire
that is supposed to pull the valve open and push it closed.
Ive had a lot of trouble with the stiff cable. The problem is that when
pushing the choke knob in,
one or both of the outer covers are forced out of the fixture at the knob end
of the cable. Both
76 TR6s I bought had cables that failed in this way. I bought a new cable for
the one that was
restored. It lasted less than a year. Bought another one and it only lasted
about 6 months.
At $50 a throw, I decided to repair the two broken cables. First tried
squeezing the crimp fitting
of the fixture on the outer cover. Lasted a few days. Epoxy next, lasted a
few weeks. Finally
designed a clamp to really squeeze the fixture on the cover. Worked for a few
days then one day
when the knob was pushed in, the stiff wire from one carb bent, folded and
broke where it connects
at the knob end. Rats! Must have squeezed the outer cover so hard that it
squeezed down on the
inner cable. Moved the clamp to the other broken cable but didnt tighten it
so much. Outer cover
came out. Made it tighter, a wire broke the next day. What a pile of crap!
The area that fails
is shown in the following photo. This cable has been repaired with epoxy.
The masking tape was to
hold the two cables in position while the glue dried. Another advantage of
the early cable is that
it can be locked in position by rotating the knob 1/4 turn clockwise.
I think this was about the time I bought that new set of carbs that were on the
76 TR6. These
carbs have spring loaded cold start valves. I bought the earlier design cable
with the flexible
inner cable. That was in 84 or 85. It is still working. Moral of the
story --- dont try to
push a wire.
The later valves can be modified to work with a spring. The valve is
disassembled, the frame placed
in a vise and the cylinder housing the spring loaded ball is driven out with a
punch as shown in the
photo below. Springs are purchased (from Moss) and installed as showed in the
right photo below.
Note that the steel ball is gone. With the spring installed, either the older
or the newer design
cable can be used. Even a cable that has failed by the outer cable coming
loose at the knob end
will probably still work with the spring loaded valve. (The cable shown
earlier had been repaired
with epoxy and used several years on a 73 that had spring loaded cold start
valves.)
Don Malling
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