Author Topic: Poor starting when hot  (Read 313 times)

Offline Muzzleloader

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Poor starting when hot
« on: 28.12. 2018 18:14 »
Hi.

My 1962 650cc Gold Flash is very  difficult to start when hot and the kill switch will only cut out one cylinder. Have Checked cut out switch, wiring and magneto end cap and centre connection.

Starts cold easily and runs really smooth and plenty of power with no misfiring.

Comments greatly appreciated

Muzz

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Re: Poor starting when hot
« Reply #1 on: 28.12. 2018 19:28 »
G'day Muzz, long time no see.
I'm no xpert on magies but that sounds very strange only cutting out one side. Could you be getting pre-ignition on one side making it "run on"? Could be a combination of timing/fuel & bias.
Cheers.
ps: Give us a clue as to here your located.
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline Muzzleloader

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Re: Poor starting when hot
« Reply #2 on: 28.12. 2018 19:45 »
Location Herefordshire uk

Online trevinoz

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Re: Poor starting when hot
« Reply #3 on: 28.12. 2018 21:42 »
Have a look at the earthing brush for the stopping problem.
The hot starting issue could very well be a failing capacitor.

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Re: Poor starting when hot
« Reply #4 on: 29.12. 2018 07:09 »
G'day Muzz.
Thanks mate, you now have a flag.
Trev is most likely right but why would it only cut one side?
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline Muzzleloader

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Re: Poor starting when hot
« Reply #5 on: 29.12. 2018 15:42 »
Thanks for the replies.  I have checked the carbon brush and continuity is good. I think an overhaul  of the magneto is a good starting point.  Will update at some point.
Ride safe wherever you are located

Muzz

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Re: Poor starting when hot
« Reply #6 on: 29.12. 2018 16:12 »
Did you really check the earth brush and not the kill switch brush?

Some earth brushes are under a screwed-on holder, like this:


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Re: Poor starting when hot
« Reply #7 on: 29.12. 2018 20:18 »
I have had engines only cutting one cylinder.
It was the earth brush, maybe it was only contacting the armature in a limited area.
Usually the armatures have a distinct hollow in one spot which needs to be machined out.

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Re: Poor starting when hot
« Reply #8 on: 29.12. 2018 20:46 »
G'day Fellas.
I remember my first problem with the A7 back in '81. She would start and run great but I couldn't stop her. Never had a Lucas magged bike before. Lucky the local library had a Lucas book. Yep that brush was gone.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7