3 replies to this topic

[Jackman]

I am currently rebuilding my carb. well will be when i get the stuff. I was wondering does anyone know how to check if the bell housing (the thingy with the piston) is too warn to use.
I have a hs4 su carb and im currently testing it as in the mini mag. However it falls to quick and they say its warn so im hoping its not.

Any ideas on how to tell?

[Jackman]

Does not matter, found out the damper is really warn. Also its not too far out so should be fine. Ill keep you posted.

[Guess-Works.com]

There is something call the drop test which I believe is detailed in the haynes manual... but basically...

Remove the spring from the suction chamber, and dashpot oil etc, then cover the two holes on the bottom of the piston with bluetac or suck like...

Push the piston to the top of the chamber and time how long it takes to fall ( remember to catch ) I think 2 seconds is about right... if less than that then the gap round the piston is too big and the must be replaced if less probably just needs a clean !.....

As with most things like this, they are machined to fit as a matching pair, so should not be swapped over from one to another, unless the drop test is being used to find a suitable partner.

[Jackman]

Mini mag says 5-7 secs is about right. Ill have a look at the haynes manual when i get home.