The Knowledge - Velocette Owners Club

is a waste of time, because you are not sorting out the stack distortion, and this is where the problem
lies. I have done this repair a few times and it works well. Take care not to overtighten the flange nuts
when refitting. Take some good advice and fit a stub and fit a rubber mounted stub fitting carb. who
gives a toss if its not original. I have a 30mm mk1 and a half stub fitting carb on my clubman and it
starts and runs, spot on. I fitted a amal velocity stack and I filed a flat on the bottom of it and I put a pad
of formica on top of the oil tank, and it rests on that and it looks great. plus no tickler to spew fuel and a
choke that is on for on and off for off. i.e. slack wire off.
# 5395 I had a Concentric Mk1 straightened by Rabers in San Jose. The jig they use to straighten the
carb basically straightens the bow in the flange which magically removes distortion from the bore, and
the slider then becomes free. The problem of a sticking sliders is as a result of over tightening the
flange nuts. The rule of thumb is that you should still be able to move the carb after tightening the
flange nuts. I was told that the jig was made by someone in the US Midwest, so there are probably
more of them out there. If you cant find someone who can do this, make sure when you install the new
carb do not fully tighten the nuts or you will end up with another piece of scrap
# 5496 The Velo parts book calls up part number M180/2 - Carburettor flange gasket, (heating
insulating). I don't know whether this is the proper item though. The description would hint that it is, but
the club spares list it as a "Gasket, carb to cyl head" which suggests that the item they sell is a plain
gasket. You would have to check with the club. I couldn't find it in Grove's list. I actually made my own
from a piece of Tufnol 3/8" sheet. Simple enough to bore three holes and shape to suit the outer
contours of the flange, then carefully blend the main hole to suit the carb and cylinder head perfectly on
either side. You will need a paper gasket on the head side unless you have the facility to cut an O-ring
groove on that side of the insulator, the carb has its own O-ring of course.
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