Author Topic: BSA A7 ss  (Read 5495 times)

Offline Ianm

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Re: BSA A7 ss
« Reply #15 on: 26.02. 2010 19:24 »
Ok. tonights the night. going from the begining. wish me luck.

Offline Ianm

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Re: BSA A7 ss
« Reply #16 on: 26.02. 2010 21:39 »
She goes ! wha who.......

Offline mike667

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Re: BSA A7 ss
« Reply #17 on: 26.02. 2010 21:48 »
She goes ! wha who.......

great - so what was wrong in the end?

Offline Ianm

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Re: BSA A7 ss
« Reply #18 on: 01.03. 2010 12:59 »
Re timed it and i think there was some sort of problem with the inner part of the fuel pipe falling apart?

I can start her really easily and she will tick over but now after running her for 5 mins. stopping then starting engine it will start but you have to hold the throttle almost wide open just to keep it running. it seems to be running quite smokey. i did clean out the carb but did not change anything other than take the washers out from under the tickler that i don't think should be there.

It also seemed to lack power ?




Offline A10Boy

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Re: BSA A7 ss
« Reply #19 on: 01.03. 2010 13:31 »
Ian

It sounds like you still have a problem.

It could be that taking out the washers under the tickler is causing slight flooding, I would put them back in and make sure theres no petrol dripping from the carb.

If that doesn't make a difference, the timing could still be retarded.
Regards

Andy

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Offline Ianm

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Re: BSA A7 ss
« Reply #20 on: 16.03. 2010 21:06 »
Nightmare!

Bike was running sweet as a nut. Booked her in for a MOT, Snapped the kick start the night before and then as i rode her down to the MOT place she started to miss and cough then stopped. would only just run on one cylinder.

Ended up pushing her to the MOT.

After i stood in the rain trying to start her but to no avail. I could just not understand how well it had run in the garage just the day before.

Any ideas,

Cheers Ian.

P.S she did pass the MOT....

Online RichardL

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Re: BSA A7 ss
« Reply #21 on: 16.03. 2010 21:39 »
Maybe a long shot, but you say you stood in the rain. Did any water migrate into your magneto pickup leads? ...or soak your air filter?
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Offline Ianm

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Re: BSA A7 ss
« Reply #22 on: 16.03. 2010 21:45 »
This all happened before the rain started.

I think it's back to the drawing board and a systems check.

Ian.

Offline Mosin

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Re: BSA A7 ss
« Reply #23 on: 06.04. 2010 17:10 »
Hi Ian,

I'm just wondering if you ever managed to get your ignition problems sorted? I'm experiencing something similar on my newly rebuilt A7ss. Due to the magneto being well and truly destroyed when the Engine blew up I've taken the opportunity to fit a Pazon Surefire in a Magneto replacement body from Paul Goff (my bike was already running 12v with a DVR2).

While the system is sparking nicely, all I can get from the bike is the occasional collosal backfire and it won't even attempt to start.

I've never set ignition timing before so I'll run through what I did to see if anyone can spot any obvious errors. I used a TDC tool from Draganfly (picture) which is marked in mm. I checked the documentation that I had and the correct advance for a Shooting Star is 3/8" BTDC (I believe that this equates to 9.5mm). With the engine in top gear and the back wheel off the ground I rotated the back wheel until the TDC tool was fully extended when screwed into the LH cylinder. I then backed the wheel off by rotating it in the opposite direction until the TDC tool had fallen by 9.5mm. I set the pazon to this using the anti-clockwise setting hole. Given that the Pazon uses a wasted spark system, it shouldn't really matter whether the cylinder was on the compression stroke or not.

I've double and indeed triple checked everything I can think of which leads me to believe that I must be overlooking something very simple.

And now I've just slipped off the kickstart and taken all the skin off my calf and I'm proper fed up  *doh*
1960 A7 Shooting Star
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Offline Stu55Flash

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Re: BSA A7 ss
« Reply #24 on: 06.04. 2010 17:53 »
Something simple: have you tried swopping the leads over. Sounds like timing.

Regards

Stu
"Keep a distance from lady "L" drivers in cars. Some are not mechanically minded, are slow to acquire road sense, an are apt to panic..." The Pitman Book of the BSA Twins.
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Online RichardL

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Re: BSA A7 ss
« Reply #25 on: 06.04. 2010 19:05 »
With the "wasted spark system" I don't think it matters which lead goes to which plug. Correct me if I am wrong. However is it possible the problem is that it is firing too late, due to the angle of the TDC finder? Take a look at the picture. If my guesses for chamber profile and plug angle are close (don't count on it), then, in this example, the TDC finder would have to go in 1/2" to detect 3/8" BTDC.

Richard L.
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Online a101960

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Re: BSA A7 ss
« Reply #26 on: 06.04. 2010 19:22 »
Use a timing disc! 35 degrees BTDC = 3/8" The tool you have is all right for a rough approximation but you are better off using a piston stop and timing disc. One thing that springs to mind is this: If the Pazon is an electronic ignition unit what are the instructions for setting it up? I would have thought that it would advance electronically and therefore maybe you are timing it in the retarded position.

John

Offline Desburnett

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Re: BSA A7 ss
« Reply #27 on: 06.04. 2010 19:31 »
Both the previous posts have full merit.
Personally I would follow the manual and ensure I had the timing side (Right hand cylinder) comming onto compression, confirmed by both inlet and exhaust valves being closed. (Wasted spark or wasted time?)
Remove the petrol tank and at TDC insert a length of stiff wire (Long enough so you dont drop it into the chamber) into the plug hole keeping it vertical. If the wire is about 1 - 2mm  dia then it will pass through the angle of the plug hole and remain vertical. Use a fixed point on the head steady to transfer a small notch or mark onto the wire.
Place a second notch or mark 3/8" above the first notch.
Back off using the method you described from TDC then back on to 3/8" BTC using the upper notch against the fixed point on the head steady. This way avoids the sine trig error caused by the angle of the spark plug hole.
At this stage the points which should have been previously set to .012" gap should just be at the point of opening with the heel contacting the lower cam.  

Online RichardL

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Re: BSA A7 ss
« Reply #28 on: 06.04. 2010 19:40 »
Des and Mosin,

I had a bit of fun doing it like this http://www.a7a10.net/forum/index.php/topic,156.msg5969.html#msg5969 . Once you get an accurate positon for the timing point, the TDC finder could be put in the plug hole to determine the setting for next time. I didn't do that, but it could happen, maybe.

Richard L.

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Offline muskrat

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Re: BSA A7 ss
« Reply #29 on: 06.04. 2010 20:19 »
G'day Mosin,
                 Richard is right about the angle of the TDC tool. A degree wheel is the way to go. The Pazon is similar to my Boyer set up and have found with it that set up by instructions is good to get going I still need to strobe at about 4500 rpm to get it spot on. The only time I have had trouble is if the battery fell of the perch (died) or had a loose connection. The timing was all over the shop and even had flames coming out the exhaust pipes (looked impressive).
Cheers
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