Timing a 48

[gregfxs]

Greetings fellow hogaholics, I'm sure someone can help. Doing a 48 for a friend total rebuild I've done many shovel's and evo's and timing is not a problem. But with a distributor I'm a little lost I pulled it to put a new gasket I locked the flywheel so it would go back in the same place. But I'm not comfortable it did plus I'd like to know for future reference I know it's like a car but I never pulled one completely out either. On the bench I brought the front cyl. to top dead center on the compression stroke with the line on the flywheel dead nuts in the timing hole. I slid the distributor in with the notch on the point cam lined up with the point rubbing block. The distributor has a bolt with a spring to advance it on start up and also slides when the bolt is loosened to tweak the timing I assume. I feel pretty lost on this so if someone could give me a distributor timing 101 I'd appreciate it. THANKS

[CraigArizona85248]

Ok... it's been a few years since I did this with a breaker point ignition.  But here is what I remember...

First of all, not trying to be picky, but it's important to know a couple of things... that line on the flywheel is not the TDC mark.  That is the 35* BTDC mark.  Secondly, the bolt with the spring on the distributor housing connects to a cable from the twist grip on the left side handle bar.  It is used to retard the timing during starting, not to advance it (the timing is advanced after starting).

First, set the point gap.  Use the kickstarter to move the motor until the points rubbing block is at the highest point of the distributor cam.  Set the gap at 0.022" (use 0.018" if this is a 12V panhead).

In order to adjust your timing, you need the distributor housing fully advanced by turning it counter-clockwise until it hits the stop.  Make sure the line on the flywheel is centered in the timing hole during the compression stroke before you set the timing (sounds like you have that part down already).  Adjust the timing so that small lobe of the distributor cam is just starting to open the points.  It can be helpful to install a test light across the points in order to determine when they are just opening.

NOTE:  The distributor cam will be turning clockwise when the motor is running so make sure you set the timing off the leading edge of the cam lobe.

NOTE:  There are two lobes on the distributor cam.  The large lobe opens the points for the rear cylinder.  The small lobe opens the points for the front cylinder.  Since we are setting the timing off the front cylinder, make sure you time to the small cam lobe.

Hope this helps.  If my old brain has missed anything or confused it, someone please correct me.

-Craig

[gregfxs]

Thanks Craig, that gives me a real good idea of what I need to do. Over the years the bikes been bastardized and the retard cable is under the tank like a choke cable, along with a lot of other things that weren't there in 48. Thanks for taking the time to explain much appreciated.

[ohio-rider]

Great advise from Craig as always.

The distributor has a bolt with a spring to advance it on start up and also slides when the bolt is loosened to tweak the timing I assume. I feel pretty lost on this so if someone could give me a distributor timing 101 I'd appreciate it. THANKS

The nut attached to the timing stem is the one to loosen, to make fine adjustments to the timing.
Yours has a spring where as this one has a cable, but be sure to keep the timing stem in the full advanced position
while tweeking in the timing. Loosen this nut, and you'll see what I'm talking about.

[panz4ever]

...Make sure the line on the flywheel is centered in the timing hole during the compression stroke before you set the timing...

Do not mean to hijack the thread, but I have a quick question for Craig. Is this the right way. The manual shows the line on the flywheel just breaking the right edge of the timing hole. What is the difference. And if starting easier is a reason I am definitely on board and will change the timing alignment. 80" pan, kick only...

We now return you to our regular programming. Thx

[ohio-rider]

I personally never had much success setting the timing with the marker in the center of the window.
It was impossible to start set that way.
I set mine just as the marker passes into the window. They are all probably different depending on all the variables
involved. Trial and error is sometimes a great last resort to setting timing. Takes longer but once you find the sweet spot for your engine, it will all be worth the trouble.

[CraigArizona85248]

I've always done my timing based on the mark in the center of the window.  But hey... there are dozens of way to skin this cat.  I say find what works for you and do it that way 

If you put the mark where it is just entering the window on the right side, that would advance your timing ~3* more then with the mark in the center.  If the mark is just inside the window on the left side, that would be the equivalent of retarding your timing ~3*.  I would think that 38* of total advance might be a bit much and cause ping, but as long as that's not happening, go for it!

-Craig

[4DWUDS]

When I set timing on my pans I would use the left side of the hole IF I was using a timing light and running the engine a little above idle,(about 1500 rpm) Use the center if timing it without running.

[chris haynes]

Panheads don't have distrubutors.

[CraigArizona85248]

Chris.... seriously... do think its really important if someone calls it a distributor or a timer or a circuit breaker?  We all know what part we are talking about.  I'm mean really?  Surely you have more constructive input.

-Craig

[MBSKEAM]

I set my breaker/distributor till it just knocks on hard acceleration on a hill then back it off till it don't, this lets you set it to the condition of the engine and gas that is in your part of the country....
but this is just my way....

it seams that the mark is to the right side of the hole for me....

mbskeam

[4DWUDS]

They don't have "Kickstands" either but who cares about being "politicaly Correct" or however ya spell it.. I do think Chris was funning us though.

[04customking]

Don't count on it...

[ElPaso 52]

I once timed to the center and the timing was too retarded to run good. My repop Panhead manual says to time to the right side of the hole and my 56 runs better when timed there.

Ron

[Kuda]

First, set the point gap.  Use the kickstarter to move the motor until the points rubbing block is at the highest point of the distributor cam.  Set the gap at 0.022" (use 0.018" if this is a 12V panhead).

Whoa! Read right through this the first time, but caught it the second. This is first I've heard of 6v and 12v having different gap settings. Since I'm about to switch back to the stock timer, can you give me any references for this? Is it in a book somewhere or something?  Makes sense, but I always like to verify... 

-Kuda
'49 panchop

[CraigArizona85248]

The "procedure" I described is just the way I've always setup the ignition.  The points gap specification came from my Haynes or Clymer Panhead manual.  I don't remember which brand it is.  Not good for much but they do have a lot of tables with this sort of data.

-Craig