Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board Strobe Timing 1968 A65 Lightning

Hello, I'm ready to strobe time the bike. I've checked the alternator face and there are no TDC or Advance mark lines on it.

I can make my own lines based on the TDC notch on the flywheel as I have the BSA tool for this.

I'm hoping there is a second notch for the full advance of 36° or whatever the appropriate full advance position is.

Can someone be kind enough to advise as to whether the second notch on the Flywheel exists and the degrees it represents?

Thanks so much
Steve

Do you know what year the crank is, best just open up the hatch and slowly turn the crank whilst looking at the flywheel. The notches will show up under a good light. Other wise mount a degree wheel on the crank when you are aligned with TDC notch and then turn it back 36 degrees and mark the alternator.

The notch in the flywheel is not TDC, it is full advance.

Thanks much for your kind replies.

Kommando, I don't know the year of the crankshaft. I have no prior repair history regarding the bike.

Gavin, I take it there is only one notch on the crankshaft? I suppose it makes it easy to find. Just back off from TDC and search for it. I suppose I can attach a degree wheel, but if known, how many degrees is the full advance position notch?

I grew tired of divining cuneiform markings and schemes of the various crankshafts and timing kit for the old bikes I work on . . .

. . . and just make my own markings for TDC and advance on a suitable rotating part using a degree wheel.

For my '66 BSA, I scribed TDC and ADV lines on the stator and and a corresponding single reference line on the rotor. Makes it nice and easy to use a strobe light even if I have to remove the primary cover (I have an early one with no inspection window).

Maybe not the answer you're after, but the schemes manufacturers have come up with (plugs, notches, fixtures, etc) in my eyes are a complication fo a simple concept.

Jason

Yes only one notch, locate the crank throught the front timing plug aperture, remove the strobe plate on the Pchaincase front (4 x c sunk 2 BA screws, ) mark the alt rotor with tippex / correction fluid immediately in line with the fixed pointer, remove the plug from the notch then use the new mark to strobe , the rotor should have a groove to line up with the pointer, if it doesnt its the wrong rotor or its been fitted backwards, if its backwards, be very worried about the competence of the last assembler.

What Gavin said, one notch at full advance. There is a tool, a sort of spring loaded plunger to find that slot in the flywheel, but I've always used an Allen key; I believe a 3/16" key fits nicely and will stay in place while you make your timing mark or perform static timing.

FWIW, the full advance timing spec for all A65s is 34 degrees BTDC, but I've never seen the timing slot in the flywheel be wrong, so I wouldn't bother with a TDC gauge. (I would be concerned about not having a service manual containing this information though.)

Jason:
what the others said

But just saying from what i can see in your pic everything looks very clean and well maintained ...

@ignoramus Thank you for the compliment.

I believe myself to be a meticulous engine and motorcycle builder. I've been doing it for about 30 years (I am guessing there are people here who have been doing it longer and better) and have learned a LOT in that time. Always room to learn more, which is why I have read this forum for a long time.

Jason