Topic: Timing plate issue

[Mikehouston]

Cb500 k1. Recently rebuilt top end. Points set at .012 gap per the manual.  When I try to set the timing the main plate will not move far enough for me to allow 1-4 cylinders to fire when the F mark is in alignment. At the plate’s furthest adjustment, it still fires well past where it supposed to. What could cause this??  Thanks!

[700504]

Advance springs might be too sloppy and old, may need to clip one coil out of them to tighten them up.

[robvangulik]

What happens when you set the gap at .013 or even .014, does it come closer?

[johnny550]

There are lot's of explanations on this forum if you search for them, but you need to place a shim in between the edge of the points plate and one of the engine bosses. As soon as you loosen the screws to adjust the plate it will be pushed side to side by the points cam and throws off your ability to set timing. You can see this pretty clearly if you try to set timing dynamically with the engine running - once you loosen the screws you will see the whole plate jumping around and it's impossible to get the timing set right until you add that shim to limit movement.

[bryanj]

Gap is 14 thou not 12

[PeWe]

Make sure that point plate sit tight and can not move sideways when its three screws are loosened making the timing to a never ending story.
I found this description at hondachopper.com  Garage.
https://motorcycleproject.com/text/sohcign.html

I hammered the bosses with a sharp metal hammer in a straight angle, (not sideways) to make them to swell so plate will sit tight. All screws were loose, hammer a little on all bosses until plate sit tight and hopefully centered.
(Another engine case I have is OK, plate sit really tight without need to hammer rhe bosses.)

Cutting the advancer springs, a must on both my bikes. CB750 use same igntion as CB500.
Pamco, stock points and Dyna-S used, same needs.

My last build could not get into correct F vs case mark at idle, plate could not be turned enough, cut springs 1/2 wound each did it (advancer not sloppy with free moving weights the first degrees).
Points at max gap helps to get it later (retarding it).

Advancer can also have a play when center nut is not tightened. Max counterclockwise matched real TDC.

The advantage of electronic ignition as Dyna-S is that ignition will not change if plate moves a little sideways.
Points work different when that happen. Points easiest to set correct and equal with dwell meter. Corrected while idling. Place a fan in front of engine when adjusting, it can take a while

Adjustment of point 2:3 is PITA since it easy moves in-out instead of follow its groove sideways only. This affect ignition too.

Hondachopper has a good description of adjusting the ignition. CB750, but same stuff and procedures.

My bike has a CB500 TEC plate since JT Marks charged less for it.
http://www.hondachopper.com/garage/carb_info/timing/timing1.html