Author Topic: a10 stalling and spitting back  (Read 204 times)

Offline madsens

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a10 stalling and spitting back
« on: 08.07. 2019 11:31 »
Hi
My A-10 has begun to stall and  backfire.
I had the top and magneto off, and after putting it all together again, and timing, setting tappet clearance, this is what happens:
Starts easy enough, and seems to run smoothly - but after a short drive when everything is warmed up the trouble starts... when stopped a traffic lights/crossroads or anything else and on idle she suddenly stalls - and when trying to start her again she backfires, and is generally very hard to get running again, then after some rest/cooling down (both bike and me  *pull hair out*) she starts ok again...
Magneto was of to be checked and works fine with Easy cap installed - can this problem be due to blocked pilot jet? worn slide? any suggestions to where to start?

For information she was running perfectly before - until a slipped magneto camring had me dismantel magneto, top was taken of to put new gasket on.

regards
Joergen

BSA A10GF 1962
Denmark

Online Triton Thrasher

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Re: a10 stalling and spitting back
« Reply #1 on: 08.07. 2019 11:46 »
Don’t theorise about a blocked jet: clean it.

Check for manifold air leaks by spraying the joints while the bike is idling.

Online RDfella

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Re: a10 stalling and spitting back
« Reply #2 on: 08.07. 2019 12:36 »
So it’s a problem only when warmed up. Either petrol is getting hot in the carb – have you got a tufnol insulator between carb and inlet? or the mag condenser is kaput.
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Online morris

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Re: a10 stalling and spitting back
« Reply #3 on: 11.07. 2019 21:50 »
Don’t overlook your timing. If the magneto has been off and you timed it a bit early it may give the symptoms you describe.
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Online morris

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Re: a10 stalling and spitting back
« Reply #4 on: 19.07. 2019 21:03 »
Hi Joerg, excuse me my curiosity but did you found the problem?
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
The world looks better from a motorbike
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Offline BSA_54A10

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Re: a10 stalling and spitting back
« Reply #5 on: 20.07. 2019 13:31 »
My  10 used to do almost exactly the same thing
By the time I had fiddled with the maggy & the carby it would fire right up and all would be good for another 1/2 hour or so..
One day it played up but would just not come good .
The carbon brushes looked a bit thin so I walked back down the road to an auto electrician to see if I could get some new ones.

The sparky looked at me and said he wondered why I took so long to come in, he heard me misfiring as I rode past.
When he sold me some new brushes I complained that they were not the same as what come out
His reply was he knows this but if I fit Lucas brushes & springs in place of the Bosh ones I had in my hand the bike will probably run all day in place of stopping every couple of hours because the Bosh brushes would have pulled back off the slip ring causing the bike to misfire and he was quite right, but I never told any one for a very long time.
I was just a genius mechanic .
Bike Beesa
Trevor