I am rebuilding a 1930 model 18 motor for a friend and wanted to confirm what the valve timing specifications are.
I have a book called Motor Cycling maintenance series Norton motorcycles 1928-55.
In the data section it says Model 18 1928-1931 compression ratio-6.0-1
Valve timing- Inlet opens 1/4" BTDC
Exhaust closes 1/4" ATDC
Ignition Timing 1/2" BTDC Fully Advanced
Tappet Clearance Cold Inlet/Outlet 0.003
Can anybody confirm that this is correct.
Hi Andrew.......the attachment if from the E.M. Franks Maintenance Book for Nortons - circa 1932 onwards. The info may be of help.
My 1930 Norton Maintenance manual lists the following data:
Exhaust opens 0.75" (or 55-60 degrees BBDC).
Exhaust closes 0.25" (or 25-30 degrees ATDC).
Inlet opens 0.25" (or 25-30 degrees BTDC).
Inlet closes 0.4375" (or 40-45 degrees ABDC).
Tappet clearance is 0.003" for both inlet and exhaust valves.
Agree with Andy as above but mine was really hard to start so l set ignition timing at 5/16 BTDC. With a bit of choke now and a few purgr kicks after a flooded carb with lifter in she starts first time...trial and error each one is slightly different
sounds very late. My 1952 (which would I think be broadly similar) does very well at the specified 5/8" ignition advance. Starts first kick on half retard with air lever closed (and no flooding in warm weather).
I agree with Ian. Why not set it to 5/8 and also mark the lever at 5/16. Too far retarded and it will be sluggish and hot.
Thanks everybody for your replies, I will try the 5/8" for the timing and go from there.