Panhead timing (??) issue

[leodavut]

Hi guys,

I have just finished building a '49 FL that's been putting up quite the fight... Had engine built, mag died, fitted circuit breaker and coil, wouldn't start bla bla bla anyway it's running now, finally

thing is, i retard the timing to start, it's usually one or two kicks and settles down to a lovely "potato" idle but when i advance the circuit breaker to actually ride the thing the idle gets very choppy and rough.

is the timing off? perhaps too far advanced once it hits the stop? more retarded from the point of starting and it dies, advanced to the stop and it won't idle nicely. once actually riding at full advance it's lovely, if i retard it's under powered. see the issue?

I'm guessing it's timed wrong, but i'm loath to re-do it after all the agg if it's not the issue. help is much appreciated as always!

[JBinNC]

That is kinda normal with the manual advance timers, but it should idle decent, if a little faster, at full advance. It should not be "choppy."

Check the full advance timing, referencing the advance timing mark on the flywheel, which SHOULD be a vertical line. Adjust the timer stop with the post & nut. If you have the advance timing correct, you should find that it starts best at about 3/4 retarded, rather than fully retarded.

Jim

[leodavut]

Man I must have timed this bike 50 times by now it’s a nightmare! I will have a look tomorrow. Interesting you say 3/4 retard, it starts easy with maybe 1/3-1/2 retard. I get confused, but this indicates that the timing is too far retarded, right?

And by choppy I just mean rough, the idle speeds up as you say, but no longer sticks to the old “potato potato”, it jumps around some but take offs and gear shifts are smooth. Take offs from the nice idle are rough and backfire, gear shifts are much less smooth

[JBinNC]

With points, put the front cylinder on the compression stroke, and the advance timing mark centered in the hole.

Attach a test light to the point lead at timer or coil, and the pointer of the test light grounded. Turn the ignition on. The points should start to break, and the light go on, just as the timer hits its advance stop. It could not be easier. You may find the motor runs better with a little more advance. The timing hole in the case is 8° wide. So, if you have the flywheel mark at the rear of the hole, that would equal an extra 4° advance over the stock spec.

Don't leave the ignition on, as it will overheat the coil if the motor is not running.

Jim

[BuddhahoodVato]

Quick and simple, if when you advance it runs shitty,
Your off the mark, period. No if's and buts.
Pans are easy to time, easy. What gets overlooked a bit is the actual distributor, is the base jumping around, make sure the MF is tight on the base shaft.
That your end play is not way to sloppy, anything between 0.05-0.07 is acceptable.
Embrace it, embrace the procedure and you will never have to do it again.

[Whoremonger]

Quick and simple, if when you advance it runs shitty,
Your off the mark, period. No if's and buts.
Pans are easy to time, easy. What gets overlooked a bit is the actual distributor, is the base jumping around, make sure the MF is tight on the base shaft.
That your end play is not way to sloppy, anything between 0.05-0.07 is acceptable.
Embrace it, embrace the procedure and you will never have to do it again.

All good advice, i would just add that rotational play should also be checked and corrected if needed.

[DoomBuggy]

Quick and simple, if when you advance it runs shitty,
Your off the mark, period. No if's and buts.
Pans are easy to time, easy. What gets overlooked a bit is the actual distributor, is the base jumping around, make sure the MF is tight on the base shaft.
That your end play is not way to sloppy, anything between 0.05-0.07 is acceptable.
Embrace it, embrace the procedure and you will never have to do it again.

I had a bear of a time with my Pan until I rebuilt the timer, that end play on the gear will mess with you something fierce. If you have a clear timing plug a timing light will show the mark dancing around if it is end play. Lightly blip the throttle and you can really see it dance.

[docmel]

All good advice, i would just add that rotational play should also be checked and corrected if needed.

Couldnt agree more: I had a 51 dialed in like no ones biz. Set timing as per manual, very easy to start, idled fine, ran great all across a Pans power band. A used basic circuit breaker set up, new points/condenser.

Then a couple of years later, it got harder to start. And of course now Im dicking with timing, carb, etc. no inprovement.

It was the circuit breaker shaft. Sloppy due to wear. You could see the lobe in the middle wobble as it ran.

Got rid of the play, and after re-tuning it after my rabbit chase, back to a two kicker......