Author Topic: running problems again..UPDATE..now back to first kick from cold  (Read 2789 times)

Online metalflake11

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Re: running problems again
« Reply #15 on: 26.11. 2012 15:40 »
Sorry Chicago, you need a new slip ring if that is a crack shown in the picture. Earlier this year I started getting sooty plugs, misfires, pinking and general misbehaviour. As you may have gathered where mags are concerned I don't mess about, I do my tests and if that does not cure the problem the mag is off to the repair man. Because I needed it doing quickly this time I used an unknown (to me) restorer. When it came back it was no different!..... Long story short the whole bike ended up at S.R.M. to get whatever was needed to put it right, be it carb, engine parts, whatever!.... After much to do, we all came to the conclusion the mag was still iffy. John put a new slip ring on, and the bike has been fine since. A magneto re-furb is only as good as the re-furbisher and if you don't KNOW they are good, they might not be. The point is, you might have a bill for a mag rebuild that is not worth the paper it is written on. I know I have!
Once the slip ring is damaged or contaminated by use of soft brushes it is more trouble than it is worth. (You MIGHT get away with with skimming it on a lathe where contamination is concerned). What looked to be a clean and undamaged slip ring on mine (but was still impregnated with carbon) caused the spark on the non timing side of the mag to advance and then retard the ignition 6 to 7 degrees in a random cycle.  The new slip ring got it to within half a degree, which is about as good as it gets. The reason changing the plugs puts things right is because even non resistance plugs have resistance and it is at its lowest when new. The spark will find the easiest route to earth, which is across the plug but as the resistance increases after just a few miles it is easier to ark to the mag body. Sorry, but that is how I see your problem. As for re-setting the timing it is not that hard to do, plenty here will guide you through it.  Good luck!
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Online a101960

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Re: running problems again
« Reply #16 on: 26.11. 2012 15:42 »
Quote
Don't forget to check for too soft mag pickups that smear graphite all over your slip ring.
Ted_Flash raises a very good point. Poor quality carbon brushes that are to soft is a well known problem. If you replace your brushes try to buy them from a good reputable source. A magneto rebuilder for example, and the same thing goes for dynamo brushes.

John
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Online metalflake11

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Re: running problems again
« Reply #17 on: 26.11. 2012 16:09 »
Where brushes are concerned. If you can write with it, it is too soft........It's that easy!
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Offline chicago

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Re: running problems again
« Reply #18 on: 26.11. 2012 22:06 »
Hi Chicago, I think with the symptoms you have experienced (richness, sooty plugs) it would be worthwhile stripping and cleaning the carb, in particular identify then clean all the small air ways, jets, and fuel ways, also check the float is not catching on the bowl and being held down, or that the float has a leak, all this does not take long and does not cost anything apart from maybe a gasket and some carb cleaner.

My bike would not tick over properly, it has a 389 carb (more or less the same as 376) which was flooding and I found the tickler (which acts as a breather for the float bowl) was blocked, before that it was the fuel supply to the idle jet was blocked.
cheers kiwigf, i did give the carb a quick clean when i got the bike but was thinking i should really buy a refurb kit and give it a good going over. i blew all the airways with compressed air and petrol, the float was ok with no petrol leaking in, but the spacer on the end off the pin that holds the float in place did seem a little to narrow and allowed the float to move side to side a bit, so prob a service kit a good idea, cheer's fella, all the best chicago.

hi there tedflash/metalflake11 and a101960. the brushes...now you mention it, i cleaned the slip ring twice yesterday, once in the morning, and about 3- hours later and was quite supprised to see how much carbon was on the slip ring after such a short time, so chances are that ive bought the crappy type with really soft carbon. i bought them off ebay, they were described as "lucas kf2 pickups" with a very misleading photo. when they arrived they were quite a bit different in design from my original pickups and had a hexegon type shape to the top of them. and the gaskets had to be choped down to fit.
so next thing on my shopping list is a decent new set of pickups. any suggestions for a good source in the uk ??.
cheer's fella's.

the slip ring...had a feeling it would have to be replaced, was quite a bad crack i would imagine its a similar situation of have a crack in a car distributor/rotor cap and sparks flying all over the place. it certainly wont be helping thing's i guess, pitty as apart from the crack it looked in very good condition, shame.
couple of questions again though,
would i be able to replace the slip ring with the magneto still in position, and without upsetting the timming ??.
also any suggestions for a know good source for these in the uk.
all the best fella's and thanks for the help, chicago
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Online metalflake11

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Re: running problems again
« Reply #19 on: 26.11. 2012 22:22 »
S.R.M. Engineering Aberystwyth have new brushes, (Correct ones) pick ups and slip ring . It will set you back about £50. Dave Lindsley Magneto's will also have them but I don't Know how much. Both will fit the slip ring which can't be done in situ I'm afraid. Both have a fine reputation and fitting the ring is not too expensive. Setting the timing is not that hard to do! We will help!  wink2 Blimey, if you are not too far away I will do it for you!
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Offline chicago

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Re: running problems again
« Reply #20 on: 26.11. 2012 23:40 »
hi metalflake, around £50, not as bad as i thought, bad news about taking the mag out to fit the slip ring though *sad2*, outstanding offer to come and do the timming for me, cheer's fella. i think i'll have a go at it though as i'll know how to do it next time.....but if i got stuck i could always pop the bike round to you if you didnt mind (if not to far from manchester) and sort you out for doing it ?. would be well after christmas though.
i'll have to start craming in info on mag removal and timming.
funny life, it was only about a week ago i was foolishly saying to the missus "i'm bored now, theres nowt to do apart for polish it". i think i'll keep my gob shut next time.
all the best fella, chicago
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Online metalflake11

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Re: running problems again
« Reply #21 on: 26.11. 2012 23:49 »
I was hoping you lived miles away! *doh*.................No seriously, have a go and if you get into major trouble bring it round............... I live in Manchester.
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Offline chicago

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Re: running problems again
« Reply #22 on: 27.11. 2012 00:09 »
cheer's fella  ;). i think should be cool though, all the best fella, chicago
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Offline KenF

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Re: running problems again
« Reply #23 on: 27.11. 2012 07:31 »
the brushes...now you mention it, i cleaned the slip ring twice yesterday, once in the morning, and about 3- hours later and was quite supprised to see how much carbon was on the slip ring after such a short time, so chances are that ive bought the crappy type with really soft carbon. i bought them off ebay, they were described as "lucas kf2 pickups" with a very misleading photo. when they arrived they were quite a bit different in design from my original pickups and had a hexegon type shape to the top of them. and the gaskets had to be choped down to fit.

Yes, many of the new pick-ups and the like that you see on Ebay come from the same wholesaler, and they've had/got a batch of pick-ups fitted with super-soft brushes and oversize gaskets. The brushes write like a 2B pencil. That might possibly be OK with a single mag, but for a twin you need brushes that write like a 2H or 4H pencil.

One of our test mags is a K2F with a couple of extra big holes bored where a K1Fs pick-up would go and opposite, so that we can see the slip-ring, pick-ups and safety gaps while the mag is running on the test rig. With one pick-up feeding a 6 mm gap (to simulate a sparking plug towards the end of the compression stroke in a high-compression engine), and with the other pick-up feeding a 1/2 mm gap (to simulate a sparking plug towards the end of the exhaust stroke), it's quite amazing how soon a pair of super-soft brushes can clag up an initially clean slip-ring with a layer of graphite on the insulating part of the slip-ring track. Within a couple of minutes, there's a ribbon of sparklets flying half-way around the slip-ring from one pick-up to the other, and all of the sparks go to the smaller of the two gaps.

If you imagine what happens in a real twin engine, whether the plug leads are connected to the correct plugs or are swapped over, all of the sparks end up going to the wrong cylinder.

Ken.
www.brightsparkmagnetos.com
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Offline renos-a10

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Re: running problems again
« Reply #24 on: 27.11. 2012 12:03 »
That's very good site and you don't pay too much.!!
Renos
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Offline duTch

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Re: running problems again
« Reply #25 on: 27.11. 2012 12:40 »

 Hey BrightSpark Ken, I think I looked at your demo a while ago, fairly impressive, and not trying to steal your thunder, but Chicargo, why don't you give BeezaMacchttps://sites.google.com/site/priorymagnetos/home a holler he's usually on here but haven't spotted him lately, is Macclesfield near you?

cheers
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Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
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Offline chicago

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Re: running problems again
« Reply #26 on: 31.01. 2013 13:07 »
hi again, not been on here for a while or been in the garage for a while aswell, hope you dont all think i was being rude not replying, just been busy with other things.
by way of a update.......
the bike is now back to starting with the first kick from cold. i think the problem was due firstly to me putting copper grease on the pivot point of the contact breaker points (maybe causing a short ?) and secondly not knowing the bike well enough, i find now that if i give a couple of short tickle's on the carb and a small blip on the throttle when starting from cold it starts first time  *smile*, she is still a little bit uneven on slow tickover but not enough to cut out. i havnt been brave enough to tackle replacing the slip ring yet, but after chatting to brian at lightning spares he thinks it should be ok for now as the crack is only on the side of the slip ring and does'nt go near the brass contacts.
i bought a colortune plug after hearing about them on here and got the the idle fuel air mixture almost spot on, good bit of kit.
i have also bought a carb rebuild kit from india and was going to rebuild the carb with new main jet, needle ect but im not to sure about the quality, has any body on here ever used one of these kits ?.
anyway the weather here in manchester does seem to be settleing down a little, we've got rid of all the snow and the sun was shinning this morning for the first time in months so with a bit of luck i might be able to get out on the old girl fairly soon. all the best fella's and once again thanks for all the help.... chicago
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Location: north west madchester.
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Bike: 1953 plunger Longstroke engine.