Topic: Igntion timing / Points opening 180 reversed

[fevah]

I thought id be mildly competant at working on an old bike after years messing round with carbs but it seems not.
I pulled my points off to go to the shop and get new ones, shop didnt have any so i thought id put the old ones back on until i source some.  Regapped the points and went to set the timing.  The manual says when the F 1-4 mark lines up points 1-4 should open and get power.  Except the opposite is happening for me, 2-3 open and get power, when F 2-3 rolls around 1-4 open and get power.  The cam/ignition advancer has a keyway so it can only go on one way so i dont understand how its reversed.  I took a photo of it before i pulled it apart and ive reassembled the same.
Please put me out of my misery and explain what ive done wrong

[Deltarider]

Have you taken apart the advancer itself and then mounted the cam the wrong way? 

[fevah]

Nope just took it off the crank?  Didnt even seem like it could be taken apart aside from taking the springs off it.
i undid the bolt holding the washer, baseplate and advancer off.
undid the 3 timing bolts.
took the base plate off. un hooked the wires from the condensors and the power feeds. unscrewed the points from the baseplate. It all seem like it can only go on one way so i dont understand

[Spanner 1]

Could you have put the 1+4 point where the 2+3 point goes ?..i.e. reversed them ?
Correct is both point fiber pieces(that ride on the cam) on the lower half of the cam....

[Raul CB750K1]

Only thing I can't think of is that you set up the gap in the wrong place. As you can see, the points plate can rotate on the base, and then, the right points sit on a "sub-plate" that can rotate over the primary plate.
 You must gap first the left points, when the cam is at the point that the opening is the biggest. Then, align the firing mark of the 1-4 cylinders, and then rotate the primary plate so the points start to open. Thus you are adjusting the points to OPEN when the firing mark is aligned.

Then you do the same for the other points and cylinders, but you don't rotate the primary plate but the secondary plate -so you don't modify the setting of the left points.

I'm talking by memory, so I don't remember whether the left points were for cyl 1-4 or 2-3. Somebody correct me if I'm wrong, but the gap in the points adjust the number of degrees the points are closed -and the coil is energized and so, stores energy-, while the rotation of the plate adjusts the moment of firing -points opening-

[Don R]

Switch the wires?

[bistromath]

yep you either have the points cam flipped 180 or you have the wires to the points reversed.

[tlbranth]

I think feve is just referring to the physical look of things. i.e. when 1,4 point begin to open, 2,3 appears in the inpection hole. I don't believe it's possible to mount the cam 180 degees off - if memory serves.
I'm baffled. How about a decent picture of what you have?

[bistromath]

the points cam can be mounted 180 degrees off on the advancer assembly.

[fevah]

Would appear that somehow the cam was off.  I accidentally seperated the cam from the advancer unit last night when i was trying to figure out the problem. I put it back on reversed, regapped and timed and now it all looks perfect. 1-4 in the inspection hole = points 1-4 begining to open and getting power.
Bike still wouldnt start but the battery was flat by then and my kick start is less than reliable. Charged the battery overnight so im hoping it will fire 2nite after work.

im certain the cam didnt seperate from the advancer when i 1st pulled it apart so im begining to wonder if the PO did it wrong then just swapped the plug leads to the cylinders around.  Will have to check the manual to see if it tells me what lead shud go to which terminal on which coil pack

[MJL]

Have you taken apart the advancer itself and then mounted the cam the wrong way? 

I did that. As a short term fix I swapped the yellow and blue wires and ran it until I could turn the cam back where it should be.

[fevah]

the manual doesnt seem to tell me which plug/lead shoud go to which coil and which point on the coil.
does anyone have a pic of how their leads run from the coils to the plugs so i can make sure mine isnt all messed up.  Seems like maybe the PO had it 180 out and swapped the leads to compensate

[Deltarider]

Would appear that somehow the cam was off.  I accidentally seperated the cam from the advancer unit last night when i was trying to figure out the problem. I put it back on reversed, regapped and timed and now it all looks perfect.

After assembling the cam and the rest of the advancer unit, make sure that the tiny, hardly visible mark alignes with the little hole in the advancer assy, right where it says TEC. I've tried to look up which manual describes this, but haven't found it yet.

[fevah]

i swapped the blue and yellow wires over and wolla it runs. well on 3.5 cylinders but thats another problem in another thread.  Thanks for all the help