Author Topic: Ongoing saga of gerrys a10 (compression)  (Read 2563 times)

Offline Gerry

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #15 on: 05.01. 2015 03:15 »
Hi Musrat, Took her for a ride and got back home about an hour ago. Went ok for about 1/2 hr then started to miss on the left hand side and when opened up would not come good on that side until I reduced the throttle opening and opened up slowly. As it got hotter it started to miss even more until I had to stop at the lights when it stopped altogether and would not start at all, so changed the plugs for the second set of new ones (first set put in this morning before the trip). Started on the right side only after a hell of a lot of kicking nothing on the left and while putting my hemet and gloves back on it cut out and wouldn't start no matter what I tried, so luckily I was on a slight down hill slope and coasted till I got to about 10 miles an hour and dropped the clutch and she started on the right side only and did not fire on the left all the way home. Took the plugs out and the left one was as new hadn't caused combustion at all!!! Am now going to check the points when on the left side firing and see if they have closed up at all. Also will replace the pick up on that side. May be I've got soft brushes as I have no idea whether genuine Lucas or otherwise. I have scraped them on a piece of paper and they both leave a mark but only light. I have also cleaned the slip ring and did pick up some crap but not excessive. The wife says "sell the b*#~dy thing!!! I have pulled the plugs earlier and they both looked dark brown on the centre electrode. Cheers. Gerry

Offline muskrat

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #16 on: 05.01. 2015 13:18 »
OK if we're back to ignition. How is it now from dead cold? Swap the pickups and leads. Re-check timing and point gap is same on both sides. Also check the valve clearances, it's getting hot down there.
Cheers
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Re: Ongoing saga of gerrys a10 (compression)
« Reply #17 on: 05.01. 2015 20:08 »
Gerry,
              I would suggest that you see if anyone in your area has a magneto test bench.
I know a bloke in Sydney with one and it is really an eye opener what can be seen while on test, everything from the voltage and current to the firing degree.

Online Triton Thrasher

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #18 on: 05.01. 2015 21:01 »
Check that a brush hasn't slipped sideways when you fitted an HT pickup.

Offline Gerry

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #19 on: 05.01. 2015 22:26 »
Hi Guys, Well it appears that the pick-up on the left hand pot has a problem, the mag was overhauled by our local expert, new cam ring, new slip ring, new mini condenser/capacitor under the points after removing the one in the armature, armature coil checked ok, bearings checked ok, points cleaned and reset. Yesterday I got intermittent firing on that side, so changed the pick up and brush and reset the points which were 0.008" not 0.012". Still not firing on that side. It seems the ride I did yesterday worsened the problem which makes it easier to find. Will remove the pick-ups today and clean the slip ring....if the grandkids will leave me alone long enough!! Bloody horn button has been given a real bashing. Good relations with the neighbors is being tested. Just went out and cleaned the slip ring with a petrol soaked piece of rag and the rag came out quite black so looks like the brushes are the problem as before I cleaned it I got absolutely no spark on the left side but after cleaning a good spark occurred. So now I have to source a decent pair of brushes. How do you know if the brushes I get are of the right hardness/softness? Cheers. Gerry

Offline Gerry

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #20 on: 06.01. 2015 01:31 »
OK took the pic-ups off checked them for resistance between the brush and the centre electrode of the plug got '0' ohms on both. Swapped the leads and pick-ups from left to right and right to left. Cleaned the slip ring with thinners, rag came out black for three times and then clean. Put all back together and no change!!! Still missing badly at idle but picks up on the left at about 2000 revs!! Have ordered genuine brushes from UK $50AU including postage. Maybe that will cure the problem. Too bloody hot to do any more in the shed. Bush fires everywhere in the hills. Cheers. Gerry

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #21 on: 06.01. 2015 06:50 »
One further easy thing you can do Gerry is to check for continuity between the brass strip on the slipring that you can see with the pick-ups off, and the body of the mag/earth. Should be, say, 5000 ohms typically. Anything from about 4K to 7-ishK ohms is possible. Mega-ohms or Open Line is bad and says the connection from slipring to coil is bad, or the coil has a break (or, just possible, that there isn't a good earth brush connection).  If the coil was rewound as part of the recent work, there shouldn't be a problem, but you never know, stuff happens. Seems as if your low tension side is probably working OK, but worth checking the condenser isn't shorting, especially if it's a steel cb assembly, and also, if it's steel, that the blade spring on the opening point isn't touching the camring in certain circs. That'll kill the low tension stone dead.  You can do a very basic check on the condenser by holding the points open with a bit of something (with the cb off the mag or the centre screw detached) and putting a meter - on its highest resistance scale - across the points. The reading should rise rapidly to Open Line, as the millivolts from the meter charge up the capacitor.  Also, if the pick-ups aren't new, they could be causing a problem. Dare you stick a finger on them, with the engine running (if it will)? Any tingles, let alone visible sparks or arcs, bad. Anyway, good luck with it. Cheers, Bill
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Re: Ongoing saga of gerrys a10 (compression)
« Reply #22 on: 06.01. 2015 20:36 »
Gerry,
              From your post, I think that you didn't have the armature rewound, just removed the capacitor and fitted one at the points.
I don't think that was a good idea, especially if the original wind is still on the armature and is at least 50 years old.

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #23 on: 07.01. 2015 13:52 »
I agree with Trev. How about borrowing a magneto.......?
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Online RichardL

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #24 on: 07.01. 2015 14:33 »
I would think that a good spark on one side and none on the other rules out armature winding as the problem. No?

My own most recent magneto problems included the cam ring slipping due to the eccentric locking pin having rotated to the point where it was not working. The next problem was eccentricity caused by rotating the cam-ring housing 180 degrees from the orientation that previously had been OK. Before discovering either of these problems I had replaced plugs, plug caps and leads and did the cleaning and brush checkup as Gerry did, thinking that was where the problem laid. It seems not, but I got some really good leads and plug caps in the deal. All this said to point at a couple of obscure reasons things don't work.

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #25 on: 07.01. 2015 15:52 »
I would think that a good spark on one side and none on the other rules out armature winding as the problem. No?


Probably, but not necessarily. If a magneto is surviving on original windings various problems can manifest in various guises, not always entirely logically. The reason I suggest swapping the mag is because, regardless of where the fault lies in the mag, at least you know you are barking up the right (or wrong) tree. If the bike suddenly runs fine on a different mag you can decide whether to investigate yourself or send it to be restored properly.
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Re: Ongoing saga of gerrys a10 (compression)
« Reply #26 on: 07.01. 2015 17:22 »
 
Quote
If the bike suddenly runs fine on a different mag you can decide whether to investigate yourself or send it to be restored properly.

When I investigate myself, would that be with regard to motorcycle technology, or are we talking something more personal?

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #27 on: 07.01. 2015 20:06 »
This is probably not the case here but I had a friend's T100 giving all sorts of ignition problems. I finally tracked the problem to the slip ring, some genius had fitted a BTH one.

Offline Gerry

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #28 on: 10.01. 2015 03:38 »
Hi Guys,.......eurica!!!! Swapped the mag for a recon' unit from my friend who overhauled mine (I decided to not have the armature coil rewound as it read the correct resistance) and couldn't start it at all..bugger. Swapped the leads over and away she went firing on both cylinders without missing a beat. At long last the saga is over....I think. Still got to take her out on a good long run before I can be absolutely sure, but the difference now to what it was is totally different.
NOW I'D LIKE TO THANK YOU ALL FOR YOUR HELP AND SUGGESTIONS, IT REALLY IS APPRECIATED. WHAT A GREAT GROUP OF GUYS YOU ARE. STAY WELL AND RIDE SAFE. KIND REGARDS. GERRY

Offline muskrat

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Re: Ongoing saga of gerrys a10 (compression)
« Reply #29 on: 10.01. 2015 07:44 »
Well that's a big relief for you and us. Shows most problems can be beat with patience and perseverance. Now if you can find time in between fire, thunderstorms and floods, enjoy the rides.
Cheers 
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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