No Spark!

Started by Thomas, October 17, 2017, 07:28:33 AM

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VicYouel

Quote from: Thomas on November 03, 2017, 11:05:56 AM
Thank you, Vic! I have two workshops here in Germany who can do the job. Tony Cooper is not answering his phone, I will try later again. What is the size of the necessary puller and where do I ask in the club? Cheers, Thomas

Contact Les Hobbs who rus the spares scheme;  See our main web site at http://marston-sunbeam.org/contact.html  for contact details.

singleminded

No there is no seal there..In theory there should not be any oil in the timing cover, but it does sometimes work its way past the pump shaft. It is wise to grease the chain from time to time as a broken timing chain can destroy the casings..

Thomas

#12
Hi all, I got the magneto sprocket off with a very simple puller. Costs almost nothing but works. There is no gasket at the magneto shaft. Is it missing or is that normal? What about oil leaks? And I got a message from Brightsparks saying that the person in charge is sitting in Montmartin de Saint Martin in the Normandy, France. They say that the UK-based colleague died a while ago.
Cheers, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

Thomas

Yes, John, a two leg puller is probably the better option. I see what I can get. Thanks a lot again! Cheers, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

singleminded

I don't think you would get the legs behind the sprocket with a puller that size, unless you remove the mag bolts and get more clearance that way. I would look for a thin jaw 2 legged puller, and be careful not to damage the teeth. But if you can get a puller in there i see no reason why the sprocket would not come off, I have done that before..John

Thomas

Very nice, John! Unfortunately I have no access to a lathe and can not make such a tool. I thought about something like this stuff: https://www.amazon.co.uk/Silverline-MS23-Gear-Puller-3-Piece/dp/B000LFVPYE/ref=sr_1_1?ie=UTF8&qid=1509730616&sr=8-1&keywords=puller
I presume it will work as well. And it isn't expensive.
Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

singleminded

#8
Here is the one i made..the outside thread is 5/8"( 0.625") x 20tpi and i used an 8mm bolt for the center. the hole at the lower end is just big enough to clear the 3/8            ( 0.375") magneto shaft thread length about 7/8"(0.875"). Also I use a small slug of brass in the end so i can't damage the magneto shaft.Screw the extractor into the sprocket and tighten the center bolt, if the sprocket does not release the a sharp tap on the center bolt with a hammer will usually free the sprocket.. John

Thomas

Thank you, Vic! I have two workshops here in Germany who can do the job. Tony Cooper is not answering his phone, I will try later again. What is the size of the necessary puller and where do I ask in the club? Cheers, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

VicYouel

Yep could be the condenser; clue might be that there is sparking across the points as viewed in semi darkness.

If it was me I would get the magneto to Tony Cooper so you can regain confidence otherwise it will be a permanent source of concern.

You do need a puller to remove the sprocket which is available from the club although I am uncertain of the leadtime as I think Les makes them to order.

It is a right old pain re-installing the magneto with the two nuts...... awful design!

Hope this helps
Vic

Thomas

Meanwhile I have checked and adjusted the points and installed a new pick-up and brush for the HT cable. I also checked correct earth and all connections. Still no spark.  :( Some fellows from a BSA forum pointed to the condenser which might be broken. I hence presume that I have to dismantle the magdyno. Do I need to get the mag sprocket off to do so? If yes, do I need a specific puller for that? Or does somebody has another hint for my trouble?
Cheers, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

Thomas

Thank you Vic & Graham!
So, that's the pick-up brush. Indeed, the oil at the brush seems somewhat suspicious. I would apply contact spray and thorough QTip cleaning. Or would I introduce even more trouble? Testing the gap separation is somewhat difficult because of limited access but I'll try to adjust to .015 of course. If all that doesn't help I will send it to an expert (thank you for the contact address, Graham). Cold season is at the door, anyway...  :-[
Cheers, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

shorrog

Hi Thomas
I believe the points gap (separation) should be .015 inch but you should still get a spark even if its .020 inch. The pick up is basically at the end of the spark plug lead where it connects to the magneto. There is a spring loaded carbon brush that makes contact with the ring in the magneto, its worth looking at this just to make sure it has not completely worn away or completely covered in oil.

The most common reason for no spark on an old bike is that one or more of the windings in the magneto have broken down. Sometimes you will get a weak spark when cold but then it fails on warming up. Also you can sometimes get a spark with the spark plug removed but it wont spark when under compression. Testing for a breakdown in the windings is not easy as it may only fail under high voltage conditions. If you do think that it is the windings that have failed then the best course of action is to send the magneto to a specialist and have it re-wound.

I had the magneto rewound on my model 9 by Tony Cooper, Halesowen, Birmingham 0121 559 2405 he did a good job and was reasonably priced.

Graham

VicYouel

The pick up brush is at the magneto end of the ignition lead. The clue you give is that it is oily. Fiddly to get at .... it is either clipped in or held in by two screws. 

Thomas

Hello everyone,
after about 30 miles on the road some days ago my model 9 suddenly lost ignition because of missing sparks. I found a list in ,,The Book of the Sunbeam" about how to remedy trouble (see attached picture). I tested according to this list. The high tension lead is intact (including a somewhat oily connection at the magneto). There is no spark without the plug by holding the cable end about 1/8 inch from metal. I hence believe that I have a problem with the magneto.

The second picture shows the situation below the magneto cover. It looks quite different to the respective image in the Book of the Sunbeam. The mimic rotates as a whole when the motor is running. It has a "fixed" cam so that the points open and close when they move over an underlying increase in a respective plate. I was not yet able to measure the point separation when they are open but would presume it to be about 1/50 to 1/60 inch. The contact breaker looks clean and not burned so that I see not need to clean or adjust it.

The last bullet talks about the "pick-up brush" but I have no idea where it is.

Does anybody had a similar problem and can give advice how to proceed?
Cheers, Thomas   
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)