The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: pedrochapala on 24.04. 2012 23:38
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here's what i've done. new spark plugs,metal high tension leads,ngk spark plug resister cover, magneto posts. all both sides. only left side firing. tried 4 different posts including wrong side and still won't fire.
HEEEELLLLP!!!!!!
i am going to take off both posts and blow some air in, and then swab with q-tip and alcohol tomorrow.
i would think that if it's the magneto,both sides would be !$%#%&?
GRACIAS/THANKS!
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Could be a major problem with the points cam so the points are only opening on one side.
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Non resister type plug caps, leads & plugs for use with magneto.
Cheers
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Is this a magneto that has been working OK in the past or what's its history? Make sure the points are opening a sensible amount (0.010 - 0.020 though normal running is about 0.012) on both sides. I would swap the leads, pickups and plugs over as complete sets to see if the problem switches to the other side. n.b Muskrat's post - you must use non resistor caps and non-resistor plugs. Remove the earth brush and clean it, I doubt this is the problem but its an easy job with the mag on the bike. Also, try it without the points cover which may be tracking out in certain conditions. In the meantime I would suggest no plug caps at all, just twist the wire onto the top of the plug. When testing for a spark I usually test the end of the HT lead against the barrel/head, this eliminates any problem with the plug or cap. If none of this works I would take the mag off, and look for issues around the slip ring, maybe lots of carbon dust caused by poor quality pickup brushes - this is a regular problem nowadays.
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Before you take your magneto off there is another test you can do.
You know that it's only firing on the left side.
Remove the right hand pick up completely and try it again. Same result?
Remove the left hand pick up and replace the right hand pick up.
See if it fires up on the right side with the left pickup removed.
If it does the problem is a contaminated slipring as Beezermacc mentioned at the end of his reply and will need to be replaced.
Beezageezauk.
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I've just re-read the original post and realise that he says it's not firing but does not say if there's a spark! Might be worth checking valve clearances and compression. ;)
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ok. more background. new pistons, rings,valve guides and valves. new magneto cover, cam and points set at 12. and new steel ring too. that whole end is new. timing is fine.
the ngk spark plug resistor covers are fine because the left side works-no problema. all new copper wire and ngk plugs.
the engine has 33 miles on it.
the right side exhaust valve was not in sync,so i reset it.
then i blew air through both openings in the magneto. then i used a mirror and cleaned with q-tip and alcohol. 1 kick start and rode it 3 miles. it still misfires slightly on right at idle or low rpm, but runs like a deer-no misfire at higher rpm. the engine is at what i call normal heat.it heats up quickly here. i don't even have a choke.
maybe i missed some dirt?
sometimes it's the simplest things i'm hoping eh!
edit: i forgot to mention. i took the plug out and although it was starting to get colour,it was also wet.
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Take the stupid resistor caps off. You've been well advised on that, above.
And make sure the plugs have no resistors in them.
With a magneto, the spark on one cylinder is always weaker than that on the other. Any problem with HT voltage will cause one cylinder to miss, before the other.
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And never use a plug with R in the model # eg BR7ES.
Cheers
PS the only exception is if running boyer micro digital ignition.
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With a magneto, the spark on one cylinder is always weaker than that on the other. Any problem with HT voltage will cause one cylinder to miss, before the other.
Why weaker? Because, brushes, plugs, wires etc. have diferenences? Because cam is not perfectly symetrical? Otherwise, are you suggesting that there is some aspect of the mag's armature or magnetic circuit design that is asymentrical? The difference being that aramture and magnetic circuit asymetry would be design related, while the others are chance or random occurances. It would be interesting (to me, at least) to know which you are referring to.
Richard L.
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Sounds like the only problem you are having is a slight misfire at tickover on the RHS. You have new pistons etc. so it might be worth doing a compression test to see if the new piston on the RHS needs more time to bed in, might just be low compression. Make sure your plug gaps are no more than 0.020". Are the exhaust pipes new? If so, are they turning straw coloured or blue? Do you have any blue or black smoke from the exhaust? Definitely remove resistor caps and plugs, the caps have as much as 30,000 ohms resistance in them. When you cleaned the slip ring was it very dirty? If it was, it is possible the carbon pickups are poor quality and will contaminate you slip ring again in next to no time.
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...the right side exhaust valve was not in sync,so i reset it....
As all the valves are operated by a one piece camshaft I don't understand what you mean by "not in sync". What did you do to reset it?
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i think the dirt is my main problem now as i may not have got it all. so at it again today with carb cleaner and a modified toothbrush and air. i,m going to check the valves again. what i mean by in sync, is that both valves on rhs are closed at same time at 10 thousands.a pro advised that forget the manuals when setting valves . for 50 years he has been doing it that way. pretending it's one cylinder,then doing the other. i started doing it that way and found it easier for my old brain.
when i went in the intake was at 10 and the exhaust was touching so may have been slightly open.
in any event it now starts on 1 kick so i'm doing something right. 2 people with about 90 years experience between them, say the spark plug covers are fine[5k] and that's confirmed by the lhs working perfectly. the plug i'm using is an ngk b8hs. my points are set at 12 and i'm going to increase that to 14.
yes at 33 miles the rings on both sides are not broken in so it needs some good highway runs but i don't want to chance it until i am happier with both sides even though i have a cell phone-jaja!
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No disrespect intended about your friends but I'd take the advice given here regarding the plug resister caps ,when I had my mag rebuilt this was specified in the tech details sent back, even if it is okay now I'm sure you're building up a problem for the not to distant future and any mag work is expensive,,these guys know what they are talking about best of luck BOBH
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no disrespect intended back atcha. check this product ngk spark plug resistor cover before making conclusions. my 2 friends also make their living repairing brit bikes only and obviously are successful at it with the years involved. we checked it out on an ohmmeter[?] before use. another friend but auto with 40 years experience. they won't damage my magneto. gracias
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no disrespect intended back atcha. check this product ngk spark plug resistor cover before making conclusions. my 2 friends also make their living repairing brit bikes only and obviously are successful at it with the years involved. we checked it out on an ohmmeter[?] before use. another friend but auto with 40 years experience. they won't damage my magneto. gracias
I don't think they'll damage the magneto either, but they will make spark less likely to occur, especially in marginal circumstances, such as an old magneto with reduced magnetism and when kickstarting or idling slowly.
Just try attaching the wires directly to the plugs. See if it helps.
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With a magneto, the spark on one cylinder is always weaker than that on the other. Any problem with HT voltage will cause one cylinder to miss, before the other.
Why weaker? Because, brushes, plugs, wires etc. have diferenences? Because cam is not perfectly symetrical? Otherwise, are you suggesting that there is some aspect of the mag's armature or magnetic circuit design that is asymentrical? The difference being that aramture and magnetic circuit asymetry would be design related, while the others are chance or random occurances. It would be interesting (to me, at least) to know which you are referring to.
Richard L.
Because the sparks on the respective sides are of opposite polarity to each other. It makes a difference, when you're needing all the HT you can get, to produce a spark.
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Set the left side inlet valve clearance when the right side inlet valve is fully open. It's very simple.
I'd be more convinced your friends were real experts if your bike was working properly.
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i am on here to depart some knowledge as well, while i am trying to fix this problem. the people i have mentioned as experts no doubt could run circles around you. i am doing what has been advised on this forum and their advice. we shall see tomorrow-si?
i have done a lot to this bike and some of my "experts" have helped me do it.
the cleaning seems the major issue right now and sorry to disappoint anyone that likes things to be more complex! i hope i can be of help to my a10m 0wners amigos!
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Pedro,
Let's slow down. Mas despacio, por favor. I'm hoping something is lost in translation in your writing. I do not argue against the expertise of your local friends and advisors, and if you were comparing them to me you might have a point. On the other hand, you are pretty new here and have not met many of our friends who are experts found here. I am just picking out one to introduce you to, there are several other multi-bike owners and restorers here who must be considered at the top of the world of A10 knowledge. Here is Richard in Western Australia (Richard I hope you don't mind my making an example of you): http://www.a7a10.net/forum/index.php/topic,2392.msg15363.html#msg15363 Perhaps your locals have a website where we can learn as much about A7/A10 engine performance as Richard shares in this one forum topic.
I think we all just need to be friendly, as fellow followers of the Piled Arms.
Regards,
Richard L.
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Richard L,
You are a nice bloke!
If you were with me now (enjoying our azure blue skies), I would give you a cuddle in a manly West Australian sort of way (or just hand you a beer!)!
Richard
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#1: Get rid of the plug caps with resistors.
#2: After #1 is done, start looking for mag problems.
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Having read the post on page 1 from Richard i agree , has he thought of applying for the job that goes with a nice white house !! What a diplomat He'd make ,BobH.
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Gents,
Those are very kind words, thanks. As for the White House, no aspirations (other than maybe being their sound system designer) , besides, I hear they do background checks.
As for the beer, on Richard's suggestion I'll be out looking for a Western Australia pint to hoist tonight. I'll let you know what I find.
Richard L.
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I used to be of the school of thought that resistor sparking plugs, caps and leads probably don't make much difference. Then I did some experiments, and I was surprised how much difference they do make. Do have a look at:
Are suppressors and resistor sparking plugs OK to use with magnetos? (http://brightsparkmagnetos.com/faqs/FAQs%20about%20magnetos%20generally/Are%20suppressors%20and%20resistor%20sparking%20plugs%20OK%20to%20use%20with%20magnetos.htm)
The conclusions I came to were: "a suppressor does appear to require the magneto to do considerably more to achieve a significantly poorer spark" and "the higher the voltages that the HT winding generates (with a suppressor), the greater the risk of breakdown of the insulation of the HT winding."
To amplify on Triton Thrasher's point about one spark being weaker than the other, the spark current is flowing from the centre electrode to the earth electrode at one plug, and from the earth electrode to the centre electrode at the other plug. The earth and centre electrodes run at different temperatures, and they have different shapes that the electrons need to jump from, and that makes a difference.
Another possible cause of a K2F misbehaving on just one cylinder is if a non-standard (too long) safety screw has been fitted on one side so that it's easier for a spark to jump the safety gap than the plug gap. The Lucas specification was that the gap should be between 6.5 and 7.5 mm (0.256" and 0.295" - 1/4" and 19/64") from the tip of the screw to the slip ring.
Cheers
Ken
Brightspark Magnetos (http://www.brightsparkmagnetos.com)
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Geez thanks Ken, I had a look also at he back and next pages, that little video was fun,saves me going to the pictures tonight!
Serious though *eek*,I discovered some info that I'd never really thought about before-you know 'The Maggie' is one of those 'oly grail' kind of things that is there and should work no matter what- and when it doesn't, the whole world melts down and as I did " nah it's not the maggie-it's fine" pretending that it has to be something else 'cos 'The Maggie' is *warn* stuff that's rarely explained in a 'sensicle' way.
Pedro, I hope you get it sorted soon,even though we're all learning lots of stuff we never dreamed of. I reckon keep it simple and find the bug, and then do the mods one by one??
Also I been trying to have a better look at your ride, but a pretty girl is in the way-any chance of a couple of naked(bike)pics??
*beer*,salut, duTch
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thanks for posting the link! gives me something to think about. i'm begining to think i'm joe bultsflk[sp?].he's the guy in the old lil abner comics with the rain cloud over his head. on my test run the other day,the bike up and died and i walked home thinking i was gonna hafta put it on the truck. took tools and extra posts. took the end cover off and discovered i hadn't tightened the points enough and they were wide open. fixed that and rode it home so yesterday i go again and my custom shifter linkage fell of. rode home in first and got the truck to retrace my route. found it-yeehaa!
went out today and rode 12 miles on country road, no problema. now i gotta tighten that shift lever with a bit of machining. those rings are not seated yet[51 miles] but i know that.
by the way-i had the ht wire tied directly to the plug after i burned and crashed. yesterday and today i put the spark plug covers back on. it's real good copper ht wire i'm using.
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There's bound to be a few hickups with the old girl. You'll sort the bugs out.
The gear lever fell off my '51 100 miles from home and could not be found. A 14mm ring spanner got me home.
Cheers
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Good to hear Pedro,it's certainly encouraging when you can actually do some miles before....nothing happens and..you get do do more miles!!
I thought the other night, and it may have been mooted in the other posts- can't remember, but I've had brand new plugs that malfunctioned prematurely(in the box), but i guess you got it sorted anyway.
Cheers ,duTch
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75 miles and counting! running like a dream
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How did you fix it?
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i hadn't tightened the points enough and they were wide open
It's sometimes the small details that makes the big problems! (but still, get rid of any resitor-caps, one day that detail may make trouble as well). Congrats on being back on the road, in the sun with all the girls lol Lucky you!
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yes,the small details. i will use the resistor caps until i can get the other. after 6 years, i can't seem to get anything i need here in mexico except spark plugs. my 2 main suppliers are in edmonton, alberta and albq,new mexico.
you blokes with parts near by is damn lucky!just under 100 miles now and running and shifting is sweet-oh yeah!
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Hi I'm new to this forum, I've had a miss on my Super Rocket, at idle for a couple of years, but recently it got so worse that it quit on one side, I checked timing, changed plug, plug lead, and plug cap. It turned out top be the magneto pick-up. It was one I bought a few years ago, with a hexagonal base, a reproduction one. I bought a Lucas NOS pick-up for $28 from Rabers in San Jose, and the problem was solved. Idles nice too. Hope you've resolved your issue.
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you found the same thing i did. those hex things are made in china and aren't worth a damn :(.
i have got parts from rabers in the past as well but got lucas posts from my guys in abq,nm and edmonton alberta. the beezer is running super and at just under 200 miles now. i think i'm ready now for some longer trips. yeeehaaa!!!!
i will post those 2 suppliers in the approp. forum on here if anyone is interested.
what a great forum this is!!!!!!!!!!!!!
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Pedro,
Always interested in new suppliers, particularly in Norte America.
Richard L.