The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: bsarider on 21.03. 2010 19:30
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Today had to resort to ringing the transporter to get home. A7 Plunger trundeling along at 45 and she just cut out no cough or splutter just nothing as if I had run out of fuel.
Stripped the carb at the roadside and found nothing,again when I got home stripped and cleaned every pin hole ,fuel pipes and valves are clear Took the plugs out they were dry, sparking like mad on both sides but they are still dry not flooded
.Took all rocker covers off to make sure the valves were going up and down and all is well.It just refuses to start pop bang or cough what can it be??? I have never failed to get a bike running to at least some degree.My last resort is to check the ignition timeing but I thought I would start with the easy bits first.Any suggestion would be appreciated.
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Sorry for the mishap. Needing transportation..., costs money, and bad for the ego!
Dry plugs... no fuel reaching for some reason? (Try again with a real good flooding, if it stops afterwards inspect fuel supply).
Magneto cutting out when hot (and working perfect again after a while).
Timing slipped (loose drive?).
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Perhaps try squirting some fuel into your carby and see if it makes a noise, if no good check timing.
Good luck.
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That's exactly what happens when the timing slips. Have you got a fiber wheel on the mag, look for missing teeth.
Good luck
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Usually if the plugs are wet then the gremlin is electrical.
If the plugs are dry then it is in the fuel system.
First pull out the plugs and stick your thumb in the plug hole. Kick the bike over with the throttle open wide, you should get strong resistance. if not on one side look for a partially open valve, if not on both sides, look at the cam & cam timing.
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I think I have got to the problem but not yet why it happened.On the firing stroke with both valves closed at 5/16" BTDC the points should just open .I find that they are not starting to open until just after TDC so somehow the timing has slipped.I need to now take the timing side off and find out why but thats another day.
On removing the points from the mag and reading the A7 workshop manual it says on page 85 5.3 Haynes "Move the spring arm off the moving contact noting that a small but vital insulating washer is interposed between the end of the pivot and the spring arm" I seem to have a solder bullet end there I need to investigate this further.I will try and get a photo of in tomorrow on the board. Thanks again everyone. Alan
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Hi bsarider
Does your bike have a manual mag or auto advance?
Static timing on the auto advance will be near TDC, to get the 5/16 figure you have to wedge the ATD fully open
Dont forget to remove the wedge afterwards *ex*
HTH
John O R