My newly rebuilt SU carbs were installed a couple of months ago and are
working nicely. I used the TRF rebuild kits, which were fine. Prior to
rebuilding, I sent the bodies out to a very popular company for rebushing
and new shafts. That's where the problem came in, and I'm just passing it
along for information for others contemplating the same thing.
When I got them back, they looked great and I started reassembling them.
When I mounted the throttle stops to the shafts with new tapered pins, I
noticed that, even with no adjustment screws installed in the throttle
stops, the butterflies didn't quite close and the stops were bottomed out.
They were nearly closed, but I could see daylight and I sure didn't want
them partly open when I was trying to adjust the slow idle speed. My
conclusion was that the holes in the shafts were drilled slightly at the
wrong angles.
I had two choices. I could have sent them back, but of course I was in a
hurry. So, I ended up drilling new holes through the shafts and the collars
of the throttle stops, about 90 degrees from the original holes. The holes
were drilled at the proper angle so that the butterflies not only closed
completely, but there was now plenty of adjustment range for the screws as
well. That completely solved the problem, and everything works fine.
The reason for this note is that I've been wondering if anyone else has had
this experience. Is there any possibility that there was a variation in the
angle of the original holes drilled at the factory in the throttle stops? I
suspect not, and that there was a just slight screw-up at the company that
installed the shafts. What do you think?
Sumner Weisman
62 TR3B
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