Howdy folks, points and timing-

Radar · Full Member Joined: Feb 19, 2008 Posts: 30

I thought I'd check the point gap and timing on my bike. It's a1978E.

The points looked great, but the timing...

y Clymer manuel tells me that the timing mark on the rotor needs to be midway between two marks on the stator.

y mark was 1/16 to 3/32 outside the stator marks to the advanced side.

I loosened the main points plate and rotated it fully CCW. That got me close, but I'm just on the stator mark or maybe a hair between the two.

Yes, I made sure the mechanical advance was fully closed/seated.

Why can't I get it midway like Clymer wants? Remember I rotated the main points plate as far as it would go.

I'm wondering now if I should be more concerned with full advance timing. Should I use my timing light to set full advance and just accept wherever idle timing lands?

Thanks,

Eric M.

Retiredgentleman

Its important that you set the static timing before using the timing light. I use an ohm meter to see when the points open. Use a wrench on the crankshaft nut to rotate engine CCW. Always check the right cylinder first and adjust the large (full) baseplate to have the "right" points open in the F area............the F area is between 2 lines. Adjust the "left" points next using the half plate as adjustment to again open in the F area. Fine tune with engine running and a timing light.
Another good tip..............I replaced those pesky phillip head screws with allen head cap screws..........nice to work with and they lock down better.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

Besides rotating, the plate also has some side to side or up and down play. In other words, it can get off center a little bit. Try playing with that adjustment as well and you should get it timed right. If you do totally run out of adjustment and no amount of fooling around will help, that can be a sign that your timing chain is stretched out. You can always enlarge the slots in the backing plate if you have to and gain some additional adjustment.

Yes, full advance timing is more critical and you should try to achieve that over idle timing. If that is the situation, it usually means your advance unit is wearing out.

jayel

points gap will affect it also, wider gap = less adjustment, smaller gap = more adjustment, gap is between .012 and .016

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

Yes, points gap, I forgot about that. I use a dwell meter and when done on a new set, the gap ends up about a measured .013" or .014". If you're setting used points with a feeler gauge, you should use the minimum (.012") or even a hair under. Used points have some pitting and the spark jumps between these pits. You can't measure with a feeler gauge between the pits. The gap you're measuring is actually not the gap you're getting. In reality, the gap is bigger. A dwell meter is the only accurate way to set used points.

Retiredgentleman

5twins; you brought up a good point. Last year when I set up my points I had to file the slot in the large backing plate in order to be able to set the timing. Probably means I've got cam chain stretch/wear.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

This didn't dawn on me until I rebuilt my top end last spring and installed a new timing chain. During the disassembly, I scribed a line from the points plate to the housing so I could install it in the correct timed position (or so I thought). With my old chain, I was nearly out of adjustment slot as well. When I started the bike after the rebuild, the timing was waaay off. Setting it correctly placed the plate about in the middle of it's adjustment slots, probably as it should be.

kingwj

It is not how wide the points open, it is when they open that's important. They are only a switch that turns off power through the coil. You can adjust timing by opening and closing the points also. Closing points advances and opening retards timing. Of course you want to be close on the gap.

jayel

egg-xctty that's why if you can't get enough advance check your point gap, a little bit goes a long ways

Radar · Full Member Joined: Feb 19, 2008 Posts: 30

Thanks, guys-

I did set the points at their widest recommended gap. I guess I thought I would allow for a little rubbing block wear.

I'm not excited to hear the timing chain may be stretched. The previous owner assured me the motor was totally rebuilt no more than 5 thousand miles ago.

I'll readjust the points to the lower limit in the window... .012- and see where I stand.

Thanks,

Eric M.

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