Long time reader/lurker, first time poster. First some background, then my questions.

Twenty-three years ago, when I was a lot younger and even dumber than I am now, if that's possible, after (quite) a few beers, another guy and I decided to build an ironhead "show bike" chopper, starting with an old hardtail Sportster frame he had in his basement. I'd provide the money, he'd provide the expertise. We located a very used '69 XLH motor and had it rebuilt at a local shop.

It didn't take me long to figure out my "buddy" had as little expertise as he had money.

Long story short, the frame and newly rebuilt motor sat in my basement for 22 years until this spring, when I decided to at least get it built enough to see if the motor would run, before throwing any more money at it. Using the factory service and parts manuals, I got it to the point of pushing the start button. To my surprise, it turned over twice and fired up on the third revolution. (The kicker isn't functional, which is OK with me. My knees are bad enough already.) After correcting a leaking intake manifold problem, it runs and idles great, even with its "new" (23-year-old) Del 'Orto Pumper carb.

Finally, my questions: It's got a manual advance, single-contact circuit breaker with points. The mechanic who rebuilt the motor told me to retard the spark, start the bike, then hook a spring to the mechanism to hold it in the fully advanced position. Is that the way it should be done? Or should the position of the spark advance change as the engine RPMs change? How was the manual spark advance/retard used when the bike was new? I know how it was installed, I'm trying to find out how to correctly use the manual advance/retard so I don't screw anything up.

Last question: My factory service manual shows only a static timing procedure for the manual advance unit. Is that good enough? Or should it be timed with a timing light and in the fully advanced position at a certain RPM, like you'd do if it had the auto advance circuit breaker installed? It seems to run best about 1/8 inch clockwise from where the fully advanced position is, both when idling and when revved up. I'd think I'd want to adjust so it's at the fully advanced position when it's running best? Is there a better way to set the timing than by static timing it, then guessing from there?

Sorry for the long post, this is a great site with some knowledgeable, helpful people on it. Thanks in advance for any replies.

YK

 

Is the advance controlled with the left hand-grip? (magneto)
A circuit breaker should be auto advance...but Im not as smart as I look

 

Your mechanic told you straight. With an auto advance and stock springs, they'd go to full advance at about 2000 - 2200 rpm, IIRC. So, if you have a setup that doesn't have the auto advance, retard to start, reach down and put to full advance. The spring is simply used to keep it at full advance while you're riding. If you plan on riding this baby much I think I'd spring for an auto advance distributor.

 

Thanks guys. What I have is definitely a manual advance circuit breaker, it matches the factory service manual exactly. I don't have the left hand grip control parts, but I'm sure that's how it was controlled originally. I was thinking of using something like a manual choke cable to control the advance position, instead of trying to find the handlebar parts and control cable/wire. Or I may end up just reaching down and retarding it manually and hooking a spring to it to hold it in the advance position after it's running.

pococj, my mechanic also advised me to go to the auto advance unit, and I probably will eventually.

Thanks again.