The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: chicago on 24.11. 2012 20:40

Title: running problems again..UPDATE..now back to first kick from cold
Post by: chicago on 24.11. 2012 20:40
hi fella's. went to start the bike today (a7 longstroke engine), bike started and then started missing, the left hand exauste was smoking. took the left hand plug out and was wet with petrol (had the same problem before on same cylinder), replaced the plug with a new one, ran ok for about 7 seconds and started missing again, tried to let it run for a minute or so to see if the missing might clear but it carried on missing, when i took the new plug back out it was wet and quite a bit hotter than the plug from the fireing cylinder. this confused me a bit as i would have expected the none fireing plug to be cooler than the fireing plug ???.
also when i was kicking it over to start it, i was getting a few small pops/backfires thru the carb.
maybe ive flooded it when going to start it (again) ??.
i did recently re set the tappets from 0.013 to 0.010 (originaly set to 0.010 when i bought it and started a lot easier)
as it was getting difficult to start from cold, after i set the tappets to 0.010 it did seem to start a lot easier and ran fine (could this be the cause).
i also had the rockers off recently, to re torque the head down, and noticed that at some point the exauste valve must have stuck as the push rod for said valve was slightly bent and had evidence on the top of hitting the edge of the rocker cup in which it sits.
while i had the plugs out i placed my thumb over each plug hole and there was enough compression to blow my thumb off the hole both sides, so would this rule out a sticking valve maybe ?? (i know not the best method to test compression)
ive got the points set to 0.012. (recently replaced)
the spark plugs set to 0.018.
and the valves set to 0.010
any advice much welcomed, cheers in advance, chicago
Title: Re: running problems again
Post by: wilko on 24.11. 2012 20:49
Are you using the right length plugs? Have a look at the used ones to see if the tips have been hitting the piston and closing up. Are they 3/8th or 1/2 inch reach?
Title: Re: running problems again
Post by: chicago on 24.11. 2012 22:31
hi there wilko, cheers for the advice, yes using champion l82c with 1/2 inch reach. and no signs of them hitting the piston. there is a blue spark from both plugs when held against the barrel.
all the best fella, chicago
Title: Re: running problems again
Post by: BSA_54A10 on 25.11. 2012 10:55
Check the firing position on both plugs.
A lot of the magneto cams are not symmetrical so you either have to stone down the high side or set the timing to an "average" position.
Title: Re: running problems again
Post by: bsa-bill on 25.11. 2012 11:09
try a couple of old plugs, give them a clean put them in and try it
New plugs these days are a lottery
Title: Re: running problems again
Post by: duTch on 25.11. 2012 11:53
Hiya Chicargo,- that's no good!
  I went on friday to collect some H4 35/35 bulbs-6volt, and got chatting with ol' mate, and one thing he put forth, is some plugs don't like maggies(or the maggies don't like the plugs?).
    He said inside the top of the ceramic insulator, which can (apparently) be unscrewed, is prone to corrosion, even on new plugs, but possible to rectify.
 Did you swap the plugs over, L> *eek*<R ? (just thought i'd stick my head in there and see if I could shoot meself as an after thought)- might make a difference?
 
Good luck, duTch
Title: Re: running problems again
Post by: a101960 on 25.11. 2012 12:44
Quote
try a couple of old plugs, give them a clean put them in and try it
New plugs these days are a lottery
What Bill says is unfortunately only to true. Some time ago I bought and fitted a set of Bosch plugs to my car. The whole set was faulty. The car would start just fine and it would rev up without any load, but as soon as I attempted to drive the plugs would break down. The engine would miss and start to die. I refitted the old plugs and all was well. I have also bought and fitted new plugs to my BSA, and I have had similar problems. Sometimes the plugs would be OK for a few miles then fail, and sometimes the plugs would not fire even though they appeared to give a healthy spark when tested outside the combustion chamber. In the case of the BSA NGK plugs seem to be the worst offenders, and I have had similar problems with the odd champion plug, although in general the Champion plugs do seem to be less likely to cause trouble. Try also swapping the HT leads and plug caps. A good diagnostic procedure is to start the bike up in the dark to see if there is any HT leakage.

John
Title: Re: running problems again
Post by: orabanda on 25.11. 2012 13:45
Check the air (choke) slide is open all the way; I have had the cable jump out of the lever, causing the air slide to not opebn all the way.

Had similar symptoms to yours, then noticed the cable issue, sorted it out, and the bike was good as gold!
Title: Re: running problems again
Post by: chicago on 25.11. 2012 15:20
hi fella's, cheers for the help. its now running again, i tried all your suggestions, first i changed the plugs for two old ones, kicked it over and it started, then after a couple of minutes started to die again. so tried re-kicking it but all i got was backfire so i took the pickups out and cleaned the slip ring, did notice a crack in the slip ring (will add photo in a bit), but nowhere near the brass contact points.
while i was there i took the ht leads out of the pickups and the ht lead and pickup closest to the rear wheel had water in where the ht leads fits into the pickup. cleaned and sprayed inside pickup with wd40.
i re-checked the points and pretty much 0.012 in both firing position
i put the plugs back in but this time swapped sides round. kicked it over and now running.
i think the issue is as quite a few people have suggested is dodgy plugs.
and with my bike running too rich on tick over wont help (wrong carb, 376/35). and no choke slide also.
ive also read on here i think, that with the ethanol/petrol petrol mix we are sold, once you flood your bike the plugs are knackerd ?.
anyway off to the shop for more plugs, fingers crossed.
once again, cheers for the help fella's. all the best, chicago
<a href="http://s438.beta.photobucket.com/user/chicargo/library/" target="_blank"><img src="http://i438.photobucket.com/albums/qq110/chicargo/th_SDC19205.jpg" border="0" alt="Photobucket"></a>
Title: Re: running problems again
Post by: trevinoz on 25.11. 2012 20:34
Just a point, Chicago,
                                     Long stroke engines have valve clearances of 0.015".
I agree with others re plugs, I won't use NGK in my bikes, Champion and KLG seem to work OK for me.

Trev.
Title: Re: running problems again
Post by: Brian on 25.11. 2012 22:40
Chicago I would pull the magneto off and get it reconditioned. If it has a crack in the slip ring that will be only one problem.

You can play around with plugs and carbies for as long as you like but if the maggy is crook it will never run properly.

The magneto is the "heart" of a british bike and if you want your bike to start and run correctly the maggy must be in good condition.
Title: Re: running problems again
Post by: metalflake11 on 25.11. 2012 23:37
I fully concur with that Brian...........  Magneto's make my life simple, if I have a misfire on one side, I swap the leads over from brush to plug. If the misfire swaps side I replace the lot. If it doesn't change sides I check the points gap both sides and if that is ok, I take the mag off and give it to my prefered magneto repair specialist. A few weeks later I fit and forget for another 10-15 years! ...........I love 'em, all petrol engines have fancy pants ignition systems these days, black box for this, sensor for that, it makes you puke!......... But! when they put a petrol engine into a private plane and an ignition failure is terminal, it's a magneto they fit every time! *yeah*
All hail  *respect* the magneto!!!
Title: Re: running problems again
Post by: chicago on 26.11. 2012 00:54
Just a point, Chicago,
                                     Long stroke engines have valve clearances of 0.015".
I agree with others re plugs, I won't use NGK in my bikes, Champion and KLG seem to work OK for me.

Trev.
cheers trev, i dont know if its possible to have a cam fitted from a later a7/a10 engine in my bike but it seems to start better/run smoother set at 0.010, when i got the bike they were set at 0.010, i did have them set to 0.013 for a while and it was a bit of a bugger to start. i am thinking im going to set them at 0.015 and see how it goes. all the best chicago.
Chicago I would pull the magneto off and get it reconditioned. If it has a crack in the slip ring that will be only one problem.

You can play around with plugs and carbies for as long as you like but if the maggy is crook it will never run properly.

The magneto is the "heart" of a british bike and if you want your bike to start and run correctly the maggy must be in good condition.
hi brian/metalflake11 cheers fella's, hope its not the magneto, firstly for the cost of refurb as im totaly skint (just blasted my last £25 on a colortune), and secondly i dont fancy my chances of getting the timming right without a load of hassle.

ive had a similar problem with the bike before with similar symptoms and turned out to be plugs first time, and points the second time, i do know the bike is running far too rich on tickover as always very sooty plugs.
plus the guy who i bought the bike off (gary) did say that the engine and mag had been reconditioned, vrm ltd in northwich (who gary bought the bike off) still had the add for the bike on there website after i bought it and it did metion on there that it had rebuilt engine and mag.
plus when i swapped the plugs over the smoke from the exauste also swapped sides, so im hopeing just a weak plug.
so lets hope its cool.
cheers fella's and all the best.
p.s i will let you all know how it all worksout with a update :)
Title: Re: running problems again
Post by: KiwiGF on 26.11. 2012 01:51
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.
Title: Re: running problems again
Post by: Ted_Flash on 26.11. 2012 07:18
Don't forget to check for too soft mag pickups that smear graphite all over your slip ring.  Good pickups should have a slot running the full length of them.
Title: Re: running problems again
Post by: metalflake11 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!
Title: Re: running problems again
Post by: a101960 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
Title: Re: running problems again
Post by: metalflake11 on 26.11. 2012 16:09
Where brushes are concerned. If you can write with it, it is too soft........It's that easy!
Title: Re: running problems again
Post by: chicago 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
Title: Re: running problems again
Post by: metalflake11 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!
Title: Re: running problems again
Post by: chicago 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
Title: Re: running problems again
Post by: metalflake11 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.
Title: Re: running problems again
Post by: chicago on 27.11. 2012 00:09
cheer's fella  ;). i think should be cool though, all the best fella, chicago
Title: Re: running problems again
Post by: KenF 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 (http://www.brightsparkmagnetos.com)
Title: Re: running problems again
Post by: renos-a10 on 27.11. 2012 12:03
That's very good site and you don't pay too much.!!
Renos
Title: Re: running problems again
Post by: duTch 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 (https://sites.google.com/site/priorymagnetos/home) a holler he's usually on here but haven't spotted him lately, is Macclesfield near you?

cheers
Title: Re: running problems again
Post by: chicago 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