Why don't old motorcycles need a distributor?

[SportsterDoc]

theres typically a marker on the advance unit or the points cam in the case of a 4 stroke, which spins with the points rotor.. the rotor spins with the crank. then there's a fixed mark on the cases to time against. In the case of a SOHC CB750 for example, theres an 'f' mark on the alternator rotor to set timing at idle, then there a 'll' mark that lines up at full advance for each set of points. Pints '1' set cyls 1& 4, whereas '2' sets cyls 2&3. also, theres a 't' mark for top dead center, but thats used for setting valve clearances, etc.

so, in comparison to a car, imagine the timing marks on the damper AND the distributor in the same cover on the crank basically combined.





on cam driven units, there's usually a timing mark on the alternator on the crank.

Thanks for helping me remember why, when my 76 CB750F was only a year or two old, I replaced the dual points with a Martek 440 electronic unit!

I had a *Hawk engine analyzer at the time, but it was no help.

The dwell meter made point adjustment on GM motors very simple, since GM distributor caps had a lift-up door for access with an Allen wrench to adjust with engine running.

Thanks for the trip down memory lane.

*Manufactured on Nordhoff Street, in Chatsworth, walking distance from where I grew up. They also made good quality automotive gauges.