Hi All,
Just joined so I can ask a question for my neighbour, he owns a 1928 Model 1 that has been restored, the restorer mentioned some problem when joining the crank parts, my neighbour is concerned that because of the difficulty encountered the valve timings may not be correct.
Does anyone have information on correct valve timing ?
Failing this any considered opinion could be helpful as a starting point.
Rgds, Roy
I can't answer as to the valve timing, someone will.
But I would have thought that if the mainshafts have not been disturbed then the timing would be on the marks..
Do you know what work was done on the flywheels?..john
Hi John, thanks for the reply.
I believe the crank was dismantled and assembled in some wrong way so the marks were not visible, does that semm logical ?
Rgds, Roy
Well, I have a model 9A and there are no 'marks' on the flywheel for timing. Every bike that i have owned or worked on has the valve timing fixed by the position of the timing side keyway in the mainshaft. The half time( crankshaft) pinion is fitted to the mainshaft by a key and then the dots on the rest of the pinions are aligned to give the correct valve timing.You have to remember that most motorcycle engines were not assembled by 'engineers' but production line workers , and everything had to go together easily.
you can get the valve timing good enough to make the bike run by setting the valves to 'rock' at top dead centre, and then set the ignition timing..john
According to "Motor cycle repair and upkeep" which is a set of of 14 weekly parts published by Newnes in 1931 the timing of a 1928 Model 1 is:
Inlet opens 0 deg before TDC
Inlet closes 60 deg after BDC
Exhaust opens 60 deg before BDC
Exhaust closes 17 deg after TDC
Max ignition advance 35 deg before TDC
tappet clearances are 4 though inlet and 6 thou exhaust.
Cheers
Vic Youel