Author Topic: bsa starfire b25, will not idle  (Read 377 times)

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MGILBERT

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bsa starfire b25, will not idle
« on: 11 July, 2019, 17:45:09 »
Hi guys.

I have for some time suffered on my B25 Starfirel with engine not idling,.currently fitted with Amal 900 concentric  Carb. Have currently replaced .
throttle slide
main jet
pilot jet
throttle stop
cleaned carb

Have also replaced condensor to cure misfire over 55mph. sorted.

Just ordered a replacement air screw.
 
Any thought/help would be appreciated.

bfn

Mike

royblackburn1@btinternet.

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Re: bsa starfire b25, will not idle
« Reply #1 on: 12 July, 2019, 01:12:26 »
Hi Mike when you say you have cleaned the carb have you gone down the fine drillings with a fine wire I used a strand of wire from a cycle brake cable then squirted carb cleaner down the holes it worked for me. Roy

A10 JWO

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Re: bsa starfire b25, will not idle
« Reply #2 on: 12 July, 2019, 12:03:56 »
Agree with Roy. Those pilot galleries block easy, I can't even see them without glasses. I use an aerosol of carb cleaner with a fine nozzle. Spray down one hole it should squirt up the other. Mine it don't squirt back in your eyes. There are some videos about this cleaning job on Youtube.

MGILBERT

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Re: bsa starfire b25, will not idle
« Reply #3 on: 12 July, 2019, 20:59:17 »
HI Guys. Checked out the you tube video and completed the job.  WE NOW HAVE A GOOD IDLE/TICKOVER.
Thanks guys.

hoogerbooger

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Re: bsa starfire b25, will not idle
« Reply #4 on: 13 July, 2019, 14:30:08 »
I've just cleaned the pilot circuit on my concentric having watches several youtube videos that suggest using a thin wire.

when I took the air screw out to probe across to the other side there seemed no need for a thin wire as a whole bicycle brake cable gear cable width went all the way through. This surprised me as I thought there was supposed to be a finer constriction into the central mixing chamber ? Is this what you found ? or was a thin wire needed ?

( my carb is an old 627 2 stroke with the screw in pilot jet ( but I've changed the spray tube to a 4 -stroke one)

MGILBERT

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Re: bsa starfire b25, will not idle
« Reply #5 on: 13 July, 2019, 15:30:23 »
To be honest i didnt try a complete cable width as the blockage is found at the 90 degree turn within the galleries, approached the 90 degree turn from both ends of galleries.
then flushed the system with carb cleaner 
BFN

elevensies

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Re: bsa starfire b25, will not idle
« Reply #6 on: 15 August, 2019, 19:19:14 »
all the above, clean all the tiny holes, and clean them often, as the ethanol in our fuel goes off if you have bike stood, blocking them again.