Author Topic: Concentric blocked idle jet  (Read 297 times)

Online limeyrob

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Concentric blocked idle jet
« on: 22.05. 2024 17:43 »
Just a heads up on a repair that worked better than I expected.
I've had a lot of trouble starting and some of that was down to a blocked idle jet on my 930 Concentric.  The carb had been standing for years and the passage to the idle jet seems to have been solid.  A lot of poking and flushing achieved nothing so I drilled the jet out to about .05 mm working from the pilot screw side and this allowed me to clear the blockage.
Then got a 5BA tap and re-tapped the thread in the carb bottom face and fitted a screw in pilot jet (020) from a Mk2.
Started straight way and settled to a steady idle.  5 BA tap was about £5 and the jet the same so its a good result for £10.
Slough 59 GF/SR

Online limeyrob

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Re: Concentric blocked idle jet
« Reply #1 on: 22.05. 2024 17:53 »
Ha, should read .5mm !!  Probably could have used 1mm but my original plan was to try is with the larger hole not get the screw in jet.
Lesson learned, I will avoid mm in future, they just mess with my mind. *smile*
Slough 59 GF/SR