points cam adjustment

it appears my points cam is 180 degrees off. when i line up the f mark for cyclinder 1&4 and then turn the 17mm nut forward the points for cylinders 2&3 start to open. ive done a search but havent had any luck. 78 kz 650b

If you look at the points cam (after you remove the 13mm bolt and 17mm nut) you will see a scribe mark on the outer edge of the cam . Looking at the advance unit you'll see a small hole in the advancer back plate. When the scribe mark is pointing towards the hole, the points cam is installed correctly.

Here's a pic:




Edit: Btw, I saw your other thread - if the bike ran with the points cam 180 degrees out prior to your coil swap your coil trigger wires may be crossed. Check that the wire (whether black or green) that connects to your left set of points (looking at the timing plate) goes to the 1/4 coil and that the wire that connects to the right set of points goes to the 2/3 coil. With the points cam installed like in the picture above that's how they should be.

OnkelB wrote:

If you look at the points cam (after you remove the 13mm bolt and 17mm nut) you will see a scribe mark on the outer edge of the cam . Looking at the advance unit you'll see a small hole in the advancer back plate. When the scribe mark is pointing towards the hole, the points cam is installed correctly.

Here's a pic:

Edit: Btw, I saw your other thread - if the bike ran with the points cam 180 degrees out prior to your coil swap your coil trigger wires may be crossed. Check that the wire (whether black or green) that connects to your left set of points (looking at the timing plate) goes to the 1/4 coil and that the wire that connects to the right set of points goes to the 2/3 coil. With the points cam installed like in the picture above that's how they should be.

i checked the trigger wires and they are going to the right coils. when i line up the mark with the hole i also have the f mark for cylinders 2&3 lined up. should the f mark for 1&4 be lined up instead?

bobbisman wrote:

i checked the trigger wires and they are going to the right coils.

Ok, then that's settled.

when i line up the mark with the hole i also have the f mark for cylinders 2&3 lined up. should the f mark for 1&4 be lined up instead?

I'm not sure if I understand your question correctly, but the scribe mark and the hole on the advancer (both outlined in red) only insures proper points cam orientation.

If the points cam is installed like in the pic the left set of points (1/4) should start to open as the 1/4 "f" mark approaches the timing mark on the crank case - when the 1/4 "f" mark aligns with the timing mark the left (1/4) set of points should be fully open. Likewise, as the 2/3 "f" mark aligns with the timing mark, the right (2/3) set of points should be fully open.

let try and rephrase. when i line up the notch on the lobe and the hole on the advancer, and then i check the timing, i see the f mark for 2&3 is lined up. the notch on the lobe will move as the engine is turned over. is the notch supposed to stay stationary? im thinking no...thanks for your help

so you can ignore the last post i made. i now see that the cam lobe and advance move in sync and that the notch on the cam lobe is 180 degrees off. how do i correct this? just take the advancer off and turn it 18o degrees?

bobbisman wrote:

i now see that the cam lobe and advance move in sync and that the notch on the cam lobe is 180 degrees off. how do i correct this?

The advance unit can only be installed one way, the lobe can be installed two ways, correctly or 180 degrees out.

If your points cam/lobe is not installed like in the pics above, here's what you need to do: Pull the advance weights (the two springloaded parts) away from the lobe, pull the lobe off the advancer shaft, turn it 180 degrees (so the notch points towards the hole) and reinstall it, make sure the protrusions on the weights fit into the grooves on the lobe and the notch/scribe mark points towards the hole and you should be golden.

switched it 180 degrees and it fired up. it took a couple hard starts but it fired up. i still dont get how it ran before with it off 180 degrees though

Glad to hear you got it going.

With the points cam 180 degrees out it could only have run with the points wires crossed.

Seems you installed the points wires correctly when you swapped the coils and found (and corrected) some po's error.

i appreciate your help onkel. now to the electrical forum to figure out why im not charging completely:)