Timing mark question

[doc308]

I’ll be helping a friend tune/ time his 1959 panhead. He has a single point automatic advance distributor installed on the machine. Q— with this type of circuit breaker, should the flywheel mark be set at the middle of the hole or to the right side of the hole ( as with a manual distributor)?

[RooDog]

Timing an old Harley, assuming a stock 74 inch low, less than 10:1, compression motor is not a precision affair.
The timing hole is 10 degrees wide, so in reality, anywhere within that window is OK.
The engine will run better with more advance than less advance, so I always time mine with the line toward the front of the motorcycle.
With that auto advance dizzy you must force the advance to set the timing, but first do be sure to set the points gap to spec. Forcing the advance requires gripping the breaker cam lobe with pliers and rotating it clockwise , against the spring pressure, to it's full advanced position while aligning the points to just breaking. How you determine "just breaking" is up to you. I use a slip of rolling paper, or cellophane from a cigarette pack between the points, and when the tension is released, that's good enough for me. Again, precision is not necessary, close enough is in fact close enough. Take it for a ride, and make any further adjustment you may feel necessary from there....
....RooDog....

[doc308]

Thanks RooDog. I may be wrong but I thought that the timing would be more on the retarded side if you set the mark at the front , i.e. left-side of the hole ( as you stated). I was taught that having the mark at the rear of the hole. ie the right side, was the more advanced setting.

I know that it's all ballpark with these old machines, but I've seen conflicting info regarding the timing mark with the auto advance distributors--some say in the center or the hole, others, to the right.

We'll be checking the timing initially with a test light and and fine tune with a strobe.

[awander]

Doc, you are correct about the position of the timing mark and whether it is more advanced or more retarded. Toward the front of the hole is more retarded, in other words, the engine has turned further before the spark occurs.

Roo, you must have not had your coffee yet!

[RooDog]

I stand corrected. LOL, fellas....
The sooner the mark comes up in the hole the more advanced it is, so the right side, toward the rear, is the more advanced position. The hole is still 10* wide, so have at it.
BTW. I don't have enough hands to use a strobe light. so I don't bother trying to go there, a waste of time on my personal rides, y'all's results may vary. LOL
....RD.....

[awander]

I've tried twice to use a strobe.

Both times all I got out of it was a face full of oil...

[doc308]

I've used a strobe many times with the clear timing hole plug. It's sometimes hard to see the mark, but I always do see it at some point.

[awander]

I tried one of those as well, and I couldn't see it.

But maybe your eyes (and/or your strobe) are better than mine!

[RooDog]

Well it's hard to hold the throttle open enough to achieve full advance. look through the glare of the plastic timing plug for an oily timing mark that may , or may not be in the window, and rotate the circuit breaker, all while kneeling on a concrete floor. and breathing exhaust fumes. Other that that, it's a piece of cake, not.....
....RD....
And that is why static timing works for me, and a lot of other owner/riders out there in their back yard, by the side of the road, or in a parking lot far from home.....

[flat38]

If you lock the timer cam in the advanced position, put your flywheel mark where you want it, pull out a plug and ground it, and turn the power on, you can rotate the timer housing OPPOSITE the normal timer rotation until the plug sparks and you will be timed perfectly.

[Andygears]

If you lock the timer cam in the advanced position, put your flywheel mark where you want it, pull out a plug and ground it, and turn the power on, you can rotate the timer housing OPPOSITE the normal timer rotation until the plug sparks and you will be timed perfectly.

Very similar to the way I do it but I set the flywheel mark, snug the circuit breaker so it can still be moved by hand, use a test light or ohm meter across points, then turn the advance cam with pliers till it just trips the meter at full advance, then snug it down and recheck. I’ve also found that open exhaust requires a couple degrees more advance and restrictive mufflers a little less.

Andygears

[Mongrel505558]

I've tried twice to use a strobe.

Both times all I got out of it was a face full of oil...

I have an open belt primary, but you can do the same approach with enclosed chain or belt. I lined up the front cylinder advanced timing mark in the center of the hole and painted a fine line with white paint on the sprocket shaft seal and the spacer I have behind the pulley. I can use a timing light without opening anything up. And I always figured advanced is to the right side of the hole when looking straight into the hole at the flywheel. Since the wheels are turning counterclockwise looking at it from this side, early is to the right.

[RUBONE]

I've used timing lights for year, decades in fact, for auto advance units but never with the clear plug. By leaning the bike to the right the oil discharge is very minimal. However my favorite on a performance machine is to use a degree wheel and adapters I have made up to fit the sprocket shafts even though the outer primary must come off if there is one.
For manual advance and initial setting of auto units I set it by static methods and generally just check it with the timing light after the setting to verify. Virtually never have to make an adjustment so the plug isn't out long.

[flat38]

This is my solution to all the various drawbacks of using timing lights. It won't work on stockers, but its great for open belt. The marks were set up using an indicator for TDC and checked with a degree wheel for correct advance. As an added benefit it also has a seal in it for the sprocket shaft to help with the tiny and not very effective aftermarket seal.
[image][/image]

[Panacea]

The timing lite takes all of the guesswork out of an auto advance system, just have a buddy lean the bike over to the right and hold the engine speed up a bit to reach full advance. Don't need a glass plug...