Author Topic: BSA A7 Problems - An update  (Read 2756 times)

Offline BSALarry

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BSA A7 Problems - An update
« on: 13.04. 2010 21:54 »
Hello All...been few months since I posted my orginal problem. Well to update you I have had the magneto rebuild and the automatic timing gear. I found the rebuild of mag was quite easy and had that done fairly quickly. The Automatic timing gear took longer as I did not have the equipment or skills to remove the fibre gear and put in new one..so I sent away to chap (it seems he is the only one in UK that does this) and few weeks later received rebuild Auto timing gear...very impressive rebuild. So...then took me few weeks with work to order new gaskets. So..following is how I made out:
Read posts here and set up right piston at 5/16 before TDC. Set points with cig paper, and took three attempts to get auto timing gear bolted on. Put new gasket on and it started 2nd kick. Had some small issues (ie dont assume the points were correctly put back when mag was rebuilt). I did pull it all apart to discover that problem..but once corrected bike runs good. HOWEVER...I now have a pretty serious leak coming from left side of engine...think oil seal on left of gear box...will post question about that in other area.
SO..thanks again for those who post here as it was reading these posts that made it so simple once I actually got going.





Online Brian

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Re: BSA A7 Problems
« Reply #1 on: 14.04. 2010 00:34 »
Welcome aboard BSALarry.

Sounds like your maggy has turned up its toes. Do a couple of basic checks, try it without the end cap on just to make sure there is no problem with the kill switch side of it and make sure the points are clean and adjusted. You can clean the pick ups but those sort of things are not likely to make it suddenly stop.

They are reasonably easy to work on but unless you have some experience with magneto's I would take it off and send it to a reputable specialist and get it overhauled. The maggy is the "heart" of your bike and a good one is very important. Whenever I buy a bike the first thing I do is overhaul the maggy regardless of how good it seems to work or even if its meant to have been done. Ever been to a rally or similar event and seen someone kicking their bike for ages to try and get it to start or even pushing them, nine times out of ten thats because they have a weak maggy. No spark no go !

If you let the members know where you are I am sure someone will be able to recommend a decent repairer in your area/country.

Offline bsarider

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Re: BSA A7 Problems
« Reply #2 on: 14.04. 2010 10:59 »
Thats good advice from Brian as I had similar problems and rode on the back of the transporter for my lack of effort,I will always overhaul the mag on a new bike next time.
Put the Mag in the vice with 2 plugs attached and earth the plugs to the body, attach your electric drill and see if it will run out of sparks mine did at only about 100rpm and it turned out the capacitor and windings would support a sparK when kicking over but not after a few more revs. Make sure the plugs are earthed though. Alan

Offline wilko

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Re: BSA A7 Problems
« Reply #3 on: 15.04. 2010 00:44 »
The fuel might be coming out of your tank, but is it getting into the bowl? As stated in tech topics check for blocked mesh screen inside the banjo connection  on carb.It happens to me often due to crud in fuel.

Offline Mosin

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Re: BSA A7 Problems
« Reply #4 on: 15.04. 2010 11:40 »
This won't fix your problems, but it will make identifying them much easier...

Buy an ignition tester that fits inline between the plug and cap like the one in this pic. Not only will you be able to see if the plug is firing under compression, it also saves you having to keep pulling the plugs out every five minutes and trying to find somewhere to wedge them where they are earthed and can still be seen as you kick the bike over. For the price it cost, I wouldn't be without mine for the world.

As has been pointed out, if there is no spark on either cylinder then the problem is certainly in the Mag somewhere. Did it stop dead or cough and splutter for a bit first? IF it stopped dead, then it does sound like a dead short to earth from the kill switch side of things.

Good luck

Simon
1960 A7 Shooting Star
1959 D3 Bantam
1994 Triumph Trident 900

North West England

Offline gold33

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Re: BSA A7 Problems
« Reply #5 on: 15.04. 2010 13:58 »
Have to agree with Brian on this, after being told by the P.O that the mag' had been rebuilt I ruled it out and played after work for a month before finally checking it. It had been rewound but had old bearings left in it and no spacers to stop the shaft from continually moving, I'm not sure how it ran as well as it did before all the other issues raised their heads.
I will, on all future purchases have it rebuilt as soon as possible.

Love your tester Simon, will have to find or make one of those.
Darren
'52 Plunger

Offline BSALarry

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Re: BSA A7 Problems
« Reply #6 on: 16.04. 2010 17:51 »
Hello All. Thanks for all the helpful hints and suggestions. What I have done thus far was to try and eliminate the kill switch, so I removed the cover from the points and tried to start, and nothing. I then removed the plugs and HT wires, thinking that I would try to clean the inside of the magneto with rag/gas. I would put the rag in and kick over the bike and try to clean the device inside. So, what I noticed is that when I am kicking the bike over, the points are not moving/turning. When I put my finger inside the High Tension area and move the wheel a little, then kick the bike over, the points will turn for few revolutions then stop. So, me thinks something is broken in the magneto or on gear/drive side of the engine. Looking at few of my manuals looks like a gearing arangement to turn the magneto, all located on the right side of the engine. So...I suspect next step is to take of the right side engine cover and exam the gears and then remove the magneto for inspection. Any thoughts??

By the way, I live in Northwood area, very close to Watford. Thanks again for your help..very useful website for me, as this is my first british bike, and although I have rebuild my MG...this is a different animal.

Larry

Offline BSALarry

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Re: BSA A7 Problems
« Reply #7 on: 16.04. 2010 17:57 »
Sorry, forgot to answer a few question. The bike just lost power and by compression slowed and stopped. So, no big drama..just no power and coasted to stop. I did notice that the engine seemed to be little noisy when I was riding around trying to charge battery...but since I have only been out about 6 times, have not got used to engine noises yet. But it did seem little chattery. Larry

Online muskrat

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Re: BSA A7 Problems
« Reply #8 on: 16.04. 2010 21:59 »
G'day Larrt, welcome aboard.
                                        Sounds like the fiber mag gear might have lost a tooth or three, or may be slipping on the taper. Pop the cover off to check.
Nice looking bike mate, looks like she might be walking away while running on the main stand (scrape marks on ground).
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline BSALarry

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Hello...I have removed the right side engine cover and inspected the magneto timing control gear. There were a few pieces of the gear wheel inside the cover. When I finally got it removed you can see that many of the teeth are missing...see photo. So, I suspect this was the cause of no spark as the missing elements were no big enough that when it arrived around to the drive gear, it would just stop turning. Does, anyone know of chap around northwood, watford that could look at magneto and change this gear??Thanks...might as well rebuild the magneto since it is out of bike!! Larry

Offline flashblack

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Re: BSA A7 Problems
« Reply #10 on: 17.04. 2010 16:47 »
Hi Larry,
             I`ve got one just like that, in a box somewhere, from when a chain snapped. Good news is, they`re always turning up on e-bay, and Draganfly do an exchange service for just under £120.

Nice bike, by the way      Rich  
build it, ride it, live it!

Online BSA_54A10

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Re: BSA A7 Problems
« Reply #11 on: 01.05. 2010 23:22 »
There is also an aluminium gear wheel.
I use them as te fiber ones are all old and some what fragile by now.
Downside is that the metal wheels are a little noisy i use.
Bike Beesa
Trevor