[TR] bushing carbs

Randall tr3driver at ca.rr.com
Mon Mar 14 15:30:17 MST 2011


> Has anyone done it for themselves and how did it come out?
> Would you
> do it again?

Yes, good, and yes.  But I wish I had read one of these articles first:
http://www.chicagolandmgclub.com/driveline00/1001/jasw.html
http://home.comcast.net/~rhodes/Tech_Carb_Bushing_Reaming.pdf

A simple 'chucking' 3/8" reamer can be had from Enco for about $10
http://www.use-enco.com/CGI/INPDFF?PMPAGE=70&PARTPG=INLMK32

If anyone cares, I did mine using a block of wood, a countersink, drill
press and suitable drill.  And Loctite.  Clamped the wood to the drill press
table and drilled a hole in it to accept the shank of the countersink, which
I then used like a center to engage the throttle shaft hole on the bottom.
Held the carb body in one hand and lowered the drill press to drill into the
other side.  First one came out a bit crooked, but I was able to straighten
it up with a 5/16" valve stem reamer (borrowed from a friend).  Second one
was spot-on, no reaming afterwards.

One of the things not mentioned in the articles above (but IIRC in my SU
carb book) is to not drill/ream all the way to the carb bore.  Instead, just
go most of the way through, and leave a thin wall next to the throttle
plate, so the shape of the bore still matches the plate.

As noted, try a new shaft (or 5/16" drill shank) in your old bushings first.
You may not need new ones.  But I sure did.  It's even possible that the
shafts were replaced once before, since for me, most of the wear appeared to
be in the bore.

-- Randall 



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