1956 BSA A10 RR USA spec. Timing gears Setup.

[thackero]

Having problems getting my 56 RR to run. Does not fire. No pops bangs or spitbacks. Magneto rebuilt . Plug leads swapped. Gas at plugs so I suspect the timing gears may not be lined up correctly. Present set up crank gear to idler dot to dot. Idler gear to cam gear line to line. Timing was set at 3/8" BTDC and both valves on the timing side were closed. What am I missing ? Anyone have apicture of the timing gear setup i.e camshaft gear , idler and crank pinion. Info in manuals seems conflicting.
Thanks

[Greybeard]

Have you had the bike running before?

[JulianS]

Pinions with marks aligned.

[Greybeard]

Pinions with marks aligned.

Yup, if I'd bought one of those very pretty oil pumps, I'd be keen to show it off! 

[muskrat]

G'day thackero.
Are you sure they are the right gears? The long stroke gears differ. Post a pic of yours.
Cheers

[thackero]

I have never had this BSA running. Those gears look like they have been lightened judging by the holes. I will try to post picture of my setup.

[thackero]

let me know if you can see this image
thanks

[Minto]

That looks right to me, 49 teeth on the idler, lined up proper. I'd go back and check your TS valves are closed when you're timing it (gap between tappet and valve stem is closed valve).
I recently had a similar issue, turned out I  had it timed after TDC rather than before. Easy to turn the motor the wrong way from TDC when setting it up for timing.

[thackero]

Now I am wondering whether I have the right gears. The 1956 parts book says idler gear is 67-335 I have 67-336 and the cam gear book says 67-337 mine is 67-338. Number of teeth on my cam gear is 44 and the idler 49. Any thoughts ?

[Minto]

My cam pinion is also 44 teeth. I reckon your valve gear train is all as it should be so check your ignition timing again.
You've checked that you're getting sparks right?

[RDfella]

idler pinion is correct at 67-336. 67-335 is idler pinion with spindle and key.

[chaterlea25]

Hi thackero,
Confirm the valve timing  with a degree disc, or a rough guide is to watch the inlet exhaust rockers open and close the valves when the piston on the same side rolls over top dead centre, both valves will be a little open at tdc
Have you adjusted the tappets correctly? adjust LH exhaust when the right hand ex valve is fully open and vice versa. same goes for the inlets

John

[thackero]

I am getting a nice blue spark. It would seem i have the right gears so I will have another go. i am in the process of changing out the carb to one that i know works.
Thanks

[edboy]

i had a similar problem with someones rebuilt engine that turned out to be a mixed up exhaust and inlet pushrod. take the pushrod covers of and plot both cylinders ; inlet closes before tdc and ex valve opens after tdc. any valve open at tdc firing stroke means no compression.

[thackero]

Carb rebuild and retiming fired first time and ran for the first time after being in boxes for over 30 years. Test ride next. Thanks for all your help.