Points advance unit

[Mikep328]

just curious, are all the CB four cylinder points plates/advance units the same from that era?  IOW, can the 400/550/750 components be interchanged?  Pics look the same to me...

[Bryanj]

Points plates yes, advancers will vary on advance curve but will physicaly fit

[Matt_Harrington]

Bryan , when you say advancers, does that mean the cam AND the weights/springs?

[Bryanj]

Yes the complete unit, inadvisable to swap parts between advance units

[Mikep328]

Does the points cam index mark on an ND advance unit point to the 1-4 or the 2-3 markings? (it can be assembled either way so wondering which is correct.)

[K2-K6]

Does the points cam index mark on an ND advance unit point to the 1-4 or the 2-3 markings? (it can be assembled either way so wondering which is correct.)

There's some really good images on here of the correct position.....but I can't readily find them.

It won't run if fitted backwards...giving crude analysis to confirm 

Finding out...install it however fitted, turn the crank to F on 1&4 (as that's indexed to crank) the cam should now be starting ramp to lift points of 1&4 set to fire those piston at the top of stroke.
The other, wrong way, it will be just starting to lift 2&3 with those piston at the bottom of stroke.

[ka-ja]

here you go, cam position notch

[Mikep328]

Thanks!  I had found some images of the TEC unit and ASSumed it would be the same but wanted to be sure.  The pics I found of the ND were too low resolution/grainy to see, including those in the service manual.