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Butterfly Disc Problem

Posted: Thu Jan 10, 2013 7:11 pm
by Gareth Rogers
Have just dismantled a spare SU carb as part of my pensioners self education programme! Got the disc off the throttle spindle ( undid the 2 screws ) I cannot seem to refit it ! There is a V shaped cut out on one side of the disc, anyone know which way round it goes?

Re: Butterfly Disc Problem

Posted: Thu Jan 10, 2013 7:38 pm
by les
Just slip the disc in the slot (there are only 4 positions ) until you find the right position.

Re: Butterfly Disc Problem

Posted: Thu Jan 10, 2013 11:40 pm
by Gareth Rogers
Thanks Les, will give it a go !

Re: Butterfly Disc Problem

Posted: Fri Jan 11, 2013 3:34 am
by mogbob
Gareth
Make sure you replace the two retaining screws with new
The risk , if you don't, is that metal fatigue ( pinching the split screw end to remove and the spreading again, after cleaning/ refitting ) risks one or two bits of metal breaking off the screw and flying into the engine.Loose metal in the combustion chambers is not to be recommended for the long life of an engine.
http://www.burlen.co.ukwill supply appropriate screws.
As you have discovered the disc edge is not square to the body of the disc and despite first glance, it's not a perfect circle
Bob

Re: Butterfly Disc Problem

Posted: Fri Jan 11, 2013 6:31 pm
by SUE482
See my post " Carburettor refurbishment" under "Useful Tips" might help.