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Timing Question

Posted: Sun Jun 05, 2005 5:38 am
by kar_the_terrible
I have a question about timing... and I wonder now if I did it right when I checked it last.

What is the general procedure for checking timing statically on a points ignition system. When should the points open and when should they close. I understand that they stay closed for a relatively long time, and its the momentary opening of the points that causes the spark. Also.... my points seem fine, but there is some blackening/charring on the shaft they make contact with... can I dress it with steel wool so the electrical contact is good again?

It seems as though my points are opening up at the full advance mark. Also should the igntion be turned on while checking timing (not the engine running, just the battery in the circuit). When I turn off the ignition and check it, the continuity buzzer on my multimeter is going off all the time... it *never* shows an open contact. yet the bike runs....

Thanks.

Re: Timing Question

Posted: Sun Jun 05, 2005 7:32 am
by TechTMW
kar_the_terrible wrote: I understand that they stay closed for a relatively long time, and its the momentary opening of the points that causes the spark.
Yes.

Also.... my points seem fine, but there is some blackening/charring on the shaft they make contact with... can I dress it with steel wool so the electrical contact is good again?
Not sure what you are talking about here ... if it's the cam (which moves the points as it rotates) there should be no electrical contact there ... there should be a rubbing block or a piece of felt that is lightly greased.

What is the general procedure for checking timing statically on a points ignition system. When should the points open and when should they close. ..... ..... ..... It seems as though my points are opening up at the full advance mark. Also should the igntion be turned on while checking timing (not the engine running, just the battery in the circuit). When I turn off the ignition and check it, the continuity buzzer on my multimeter is going off all the time... it *never* shows an open contact. yet the bike runs....
The easiest way to do this is to use an Analog Ohm meter. If your meter uses a tone that's fine too. When you use your ohm meter, you want the system to be discharged and isolated ... that means you want to remove the battery !!! When you check points timing statically, you are only checking for resistance. One ohmmeter lead should be connected to a good ground (on the engine preferably) and the other lead should connected to the wire leading to the coil.

When you rotate the engine, (IN THE PROPER DIRECTION! :wink: ) you need to pay attention to the ohmmeter. The exact instant the needle jumps to infinite resistance, that's the place your plug fires. (the exact moment the points open, in other words) This should occur on a designated place that is engraved on the points plate .. (usually maked with an "F".) The other marking here usually indicate "T" for tdc, and usually "||" for full advance.

Be sure that you are not timing the bike 180 degrees out. Also, be very careful while timing - USE A PROPER SIZED SCREWDRIVER! to prevent stripping a screw head (Which are a PIA to replace.)