The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: 427Thunderbolt on 29.07. 2016 03:00
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My foot hurts.
What am I missing? Magneto just came back from total rebuild and updated with the little condenser plate under cap. Doug's Cycle Barn did it and it looks like he did a really nice job.
Here is what I've done.
Brand new carb....fuel is getting to carb.
New plugs...gap is set to .020
New Plug wires
Points gap is .012 and it opens to that in both spots during a revolution.
I set timing by finding tdc on compression stroke ( valves are closed and I can feel lash ). Then I backed piston back clockwise opposite direction of engine rotation 3/8 inch and marked my rod that is touching piston face. I ran it down further a ways and then brought it back up to my mark to get any gear lash out. At this point I tightened the auto advance nut with it fully advanced and about .002 opening on the points. When I kick it over and over and over and over and over every once in awhile it puffs some weak flames out of the heads. Exhaust is off because its hard to see the points when pipes are on. I was only going to run it for a few seconds then put the pipes on.
Spark plug clamped to the block has spark but I'm not sure if its good or bad since I don't have anything to compare it to.
This is damn frustrating.....
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Try swooping the HT leads over, always happens to me after any timing changes.
If that fails, ensure you give the carb plenty of tickle until the fuel runneth over.
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Did you re-check the timing after tightening the nut on the auto advance?
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Try swooping the HT leads over, always happens to me after any timing changes.
Yep, 'swapping' the leads was my first thought too- friggin' spell-check/ predictive text! Otherwise keep a kickin' *conf*
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Try reducing the plug gaps to about 15 thou, as you may have a weak spark. If the bike starts then consider a mag fault. You haven't said why you replaced the other bits as well as a mag rebuild, or was the re-build just a new condensor. Always worth just replacing/renewing one bit at a time.
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TDC 3/8" try 5/16" and points 2 thou open try a cigarette paper just releasing maybe the combination of those two plus a large plug gap is the culprit . Unless the plug lead swop sorted it into some sort of life .
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As TT said, re-check timing after the auto advance nut is tightened. They can, and quite often do, move.
Cheers
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It's alive ! Switch plug wires and it started on the very first kick ....no kidding ! It sounds absolutely great .
Thanks for the help everyone !
Chad
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^^^ Excellent. & winner of the 'Best Easy & Free Fix" Award 2016.
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It's alive ! Switch plug wires and it started on the very first kick ....no kidding ! It sounds absolutely great .
Thanks for the help everyone !
Chad
Ha, I had the very same thing when my engine was rebuilt, lots of kicking, cursing and aggravation for a very simple fix
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Thank the lord for that, I was getting worried!
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I haven't slept for two nights
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Rather than start a new thread, I hope it's OK to post on this one.
I have seen various BTDC timing points mentioned in posts for the A10 Golden Flash.
Sorry if this has been raised before but I have a BSA Service Sheet and a Haynes Manual showing 11/32" but an old BSA Instruction Manual showing 13/32".
I doubt in practice I will get anywhere near the accuracy that the difference will cause an issue but thought I would post this for interest's sake! I am going to use the majority measurement of 11/32" ;)
Brian
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....Sorry if this has been raised before but I have a BSA Service Sheet and a Haynes Manual showing 11/32" but an old BSA Instruction Manual showing 13/32".
A bit late but I came across your post while searching for mag timing. Re: 13/32"; have a look at this page from the A7 A10 Wiki taken from the owners manual: http://www.bsawiki.com/chaps/10-chapter02 (http://www.bsawiki.com/chaps/10-chapter02)
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I bought one of these a few years back. I always buy the appropriate tool for the job because it simplifies things. http://www.davelindsley.co.uk/magneto-timing-detector.html Far more accurate than cigarette papers. I am not sure about this one offered for sale by Dave Lindsley because it doesn't say, but my one also has a buzzer. I think if I remember correctly I got mine from Magneto Ignition Supplies, but I am not absolutely certain about that. Anyway, it is a great tool and makes a fiddley job so much easier. By the way Greybeard, with modern petrol 3/8 B.T.D.C. might provoke pinking.
John
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By the way Greybeard, with modern petrol 3/8 B.T.D.C. might provoke pinking.
11/32" here with an auto AR unit
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Thank the lord for that, I was getting worried!
No mate- thank Billy Bream... *beer* *respect*
Try swooping the HT leads over, always happens to me after any timing changes.
If that fails, ensure you give the carb plenty of tickle until the fuel runneth over.
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Years ago the setting was 3/8 or 11/32, depending on model, but with modern day fuel it normally pinks like crazy thats why people are setting it to 5/16 btdc
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hi everyone , glad to here you got the bike going after swapping the plug leads , I wish mine was as simple, ive done everything as you did , ive been kicking and kicking for hours , its fired twice , ive tried other carbs , keep checking the timing using a disc and dipstick , what I have now is after priming the carb I try to kick it over and the compression is very hard indeed almost impossible to turnover, but if I remove the plug leads it will kick over normally . any ideas welcome , tw
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...I try to kick it over and the compression is very hard indeed almost impossible to turnover, but if I remove the plug leads it will kick over normally...
This makes me think that the timing is very advanced.
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thanks greybeard , I will look at it again tomorrow , tw
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I have actually had this problem years and years ago.
I had assembled my bike with the parts I had, all in rough shape.
I could kick the bike over fine with the plugs out, put the plugs in and I could barely punch it over. Matter of fact I actually managed to break the outer gearbox cover trying. I put it all back in boxes and put it in the garage rafters.
Turned out the bushings on the inner and outer gearbox covers for the kicker arm were shot, and the ratchet mechanism was junk. The added compression of the plugs must have been just enough to completely cock the whole mechanism and jam it near solid.
Plugs out, kicked over smooth. Plugs in, it got harder and harder to kick over until I cracked the bushing out of the cover.
Simple fix, but for the 20 odd years it sat in the rafters I imagined all types of horrors....
Lee
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hi lee, mine kicks over ok with the plugs in but leads off , with the leads on its almost impossible to turn it over , I have had a look at the timing again and it was advanced , to about 10 deg btdc ive been trying the fag paper method but its on a hump or magnet in the magneto , I am thinking is it before this hump or after or dead in the middle ( can anyone tell me) there has even been a tiny spark while ive been trying . I am hoping its not the same prob as lee but the simptems are different thanks tw any info is value to me
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Tumbleweed, first rotate the points and make sure you get a gap of approx 12 thou ,that they are clean and flat then with BTDC set and auto advance off it's taper ,turn the points with fag paper between them until it just begins to allow the paper to slid ,fix the auto advance with the weights jammed fully advanced back on the the magneto ,check points haven't moved ,bob s your uncle ,done . *smile*
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thanks topdad, it takes some doing with the magnet it tends to flop one side or the other patience is needed I suppose . tw
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Patients,
Or to needle nose vise grips.
Someone might have the idea of taping the jaws of these two vice grips with a lot of electrical tape to make them "soft jaws".
Then set the points gap.
Rotate the points where you want and clamp jaws on the cam ring in front and in back so the points can't easily move. Gently tighten the AA unit and check timing.
I ***** around trying to set them but they always moved. After about 20 failures I used the needle nose vice grips and hit it the second time.
Just be gentle, the grips just help enough to get the job done.
Lee
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good info thanks very much , I can stop them riding either side of the hump , tw
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I use a timber wedge (1/2 a timber cloths peg) between the post & camring. Same for the AA unit.
Cheers
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I may have missed something *conf2*, but when setting the points gap I just let the lobe sit anywhere in the minor diameter of the cam-ring and check in a couple of spots (@ just after fully open and just before closing) for each side ......when happy rotate the breaker plate to the 'just opening' position and with a wedge in the ATD to hold it, tighten the nut remove wedge; Happy days *smile*.... seems to work ok
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I'm with Dutch , fingers crossed I've never had aproblem with the mag moving .
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Either you guys are lucky, or my stuff is junk. Its probably my stuff. *conf*
I would get the firing gap just where I wanted it, and the armature would either slip backwards down the ramp face just when I touched the AA unit, if not then certainly when I tried to tighten it.
So of course I tried to trick it by deliberately setting it to advanced or retarded, always turned out too advanced or retarded. *conf*
The little pair of vice grips really helped me out here.
Also this was a brand new repop AA unit. The taper only had two settings, too loose, or too tight to turn the points plate by hand.
I will let you guys know how the AA unit turns out. At least it fit in the space provided, *smile*
Lee
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Lee ,I don't think your gear will be duff ,just must be lucky or more ambi whatnot than I realised :D *doh*
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Either wedge the points with a peg just before they open or even better get somebody else to hold them
Wedge open A/R unit and give it a tap with a slightly bigger socket than the nut needs to locate it on the taper
Tighten nut job done