Author Topic: Won't start when hot  (Read 1738 times)

Offline clive f

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Won't start when hot
« on: 23.07. 2011 17:53 »
Hi everyone I have now successfully put together my forks and the A7 has now got an mot, however there is a problem, the bike is an easy starter when it is cold but the longer you ride it the less it wants to idle and if the motor stops it is a pig to start. I am thinking it is a carb problem.

Any thoughts out there?
1948 BSA A7 (Rigid)
1962 BSA C15 Star
1958 BSA A7 (swingarm)
1978 Honda CD175
2004 Triumph Bonneville T100

Offline A10Boy

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Re: Won't start when hot
« Reply #1 on: 23.07. 2011 18:04 »
Yes, either too rich or the mag is faulty. They can fail when hot, the windings break down or the condenser packs up. The problem is, that if you take a plug out to check the spark, it can spark because its not under compression. Try closing the gaps next time it happens. Do the plugs look like its running rich?
Regards

Andy

1960 A10 - Black Golden Flash
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Online muskrat

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Re: Won't start when hot
« Reply #2 on: 23.07. 2011 21:51 »
G'day Clive,
                most home tuners (and some shop ones) don't bring the bike up to full operating temp before adjusting the pilot and idle. It should take a good 10 minute ride before setting them. So if you can get that part right and it plays up later it points towards the mag as Andy suggests.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline Goldy

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Re: Won't start when hot
« Reply #3 on: 23.07. 2011 22:20 »
Have you got a thick insulating gasket between the carb and the head, because if not heat can be transferred to the carb body and cause the type of problems that you refer to.
56 A10 Golden Flash - Restore, ride, relive.                                          
56 C12 BSA project ongoing

Offline clive f

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Re: Won't start when hot
« Reply #4 on: 23.07. 2011 22:27 »
Cheers guys this is good, I now hav lots to check and tryout to get the bike running right.
1948 BSA A7 (Rigid)
1962 BSA C15 Star
1958 BSA A7 (swingarm)
1978 Honda CD175
2004 Triumph Bonneville T100

robroy

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Re: Won't start when hot
« Reply #5 on: 22.01. 2012 13:39 »
Hi Clive
Did you get to the bottom of this?

My A10 displays identical symptoms very frustrating, mine also feels like it loses power as it warms up

Cheers

Rob

Offline renos-a10

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Re: Won't start when hot
« Reply #6 on: 22.01. 2012 17:46 »
 G'day all

 My opinion is magneto.My A10 had the same problem and i send in england for recondition.The problem solved.

Cheers
1954 BSA A10 Plunger
Cyprus

Online beezermacc

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Re: Won't start when hot
« Reply #7 on: 22.01. 2012 18:36 »
Robroy - I've sent you a PM - hope this helps.
Priory Magnetos Ltd - A10 spares, magneto and dynamo refurbs. www.priorymagnetos.co.uk

Offline jfligg

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Re: Won't start when hot
« Reply #8 on: 22.01. 2012 22:49 »
Hey Have you checked to see what your not getting when its hot?  Are you loosing spark?  What do the plugs look like?  Have a look at the points on the left side of the mag.  Good Luck Jeff

Offline Felters

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Re: Won't start when hot
« Reply #9 on: 15.02. 2012 21:04 »
Somebody a lot smarter than me once said that 80% of all carb problems are electrical. I'd bet you £5 to a bag of conkers that the mag is knackered.
'59 BSA A7 and '02 BMW 1150RT

Offline wilko

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Re: Won't start when hot
« Reply #10 on: 15.02. 2012 21:12 »
Somebody also said most mag problems are carby faults! Hope that helps??