timing suggestion for EL (1950)

[devon john]

The ‘correct’ place according to Harley (in 1940/50’s) is to the right of the hole.
However, the Clymer manual was written later, and I have my suspicion the difference is based on the fuels available when the info was made available.

The timing/tuning is based on running on the fuel quality. These bikes tuning specs were based on ‘regular gas’ of what was avail at the time which was :

In 1946, USA average fuel octane was 79 regular, 85 premium.. !
By the late 50’s it was 90 regular, 98 premium…
Our fuel in UK is 95….so clearly will need a greater advance factor on timing.

THEREFORE, I run mine in the centre (more advance) to allow for the increase in fuel octane.

Strobe is best way to do the timing, as the engine is running all the slack/lash in the timing gears is eliminated, but can be messy if doing thru the hole on a side stand….much less messy if the bike is upright. Doing it with the bulb on the points does not always allow for the slack/lash, so it may be prudent to time it just slightly to the right of centre to allow for this.
I’ve got a timing mark pointer inside the primary that I made….it points to a mark on the engine sprocket…so although the primary has to come off to check/set, I know its spot on.
this was sent to me by a engineer friend of mine
john

[RooDog]

First of all, disregard anything Clymer, Haynes, or Chilton have to say and stick with the official Harley specs unless You Know otherwise.
Secondly< the factory compression spec on the 61 inch EL series is only 7:1, so how critical can ignition timing be. That timing mark, full advance, like stop signs and speed limits, is only a sugestion. Once the bike is up and running the timing may need further adjustment. And if it starts & runs well, then you haer home free, regardless of wht the recomenations are..... Now go ride it hard and long, the way my sister likes it...... RooDog

[awander]

With the timing mark at the right side of the hole, the ignition timing is MORE advanced.

Centering the mark RETARDS the ignition timing.

Think about it-when the mark is at the right side, it is moving toward the center-so it isn't there yet. So firing the plugs when the mark is at the right side of the hole fires them earlier.

[awander]

Also-you say that your 95 octane gas "clearly will need a greater advance factor on timing"

This is not correct.

Higher octane gas ALLOWS more ignition advance, but it doesn't REQUIRE it.

[Mark44]

Also-you say that your 95 octane gas "clearly will need a greater advance factor on timing"

This is not correct.

Higher octane gas ALLOWS more ignition advance, but it doesn't REQUIRE it.

Precisely, and this is because the additional octane reduces pre-ignition, so the timing can be a bit more advanced without causing pinging.

[devon john]

With the timing mark at the right side of the hole, the ignition timing is MORE advanced.

Centering the mark RETARDS the ignition timing.

Think about it-when the mark is at the right side, it is moving toward the center-so it isn't there yet. So firing the plugs when the mark is at the right side of the hole fires them earlier.

that makes sense ,,,,, i was just passing on what a friend had suggested ,,, as you point out i think he's wrong

john

[Doc37W]

If you want to time the EL with a strobe light while running, get a clear plastic plug made for timing H-Ds. Wrap black electrical tape around the part of the plug that sticks out (to allow more light from the strobe to illuminate the timing mark). Turn the plug in until it hits the flywheel, and back it out a quarter turn (Again, to allow you to see the timing mark, by lessening the amount of oil between the plug & flywheel). Make sure the points gap is .022", spark plug gap is .028". At full advance, running, you should see the timing mark on the right side of the center of the hole (I prefer to have just a little sliver of flywheel showing to the right side of the timing mark). If not, adjust the timer plate by loosening the nut on the control wire stud and moving the stud a little. Retighten and check timing. The closer to the right edge of the hole the timing mark is, the more advance the ignition. AFTER you get the timing correct, THEN you can adjust the carb for best idle and performance, not before. Doc

[panfreak]

I only look in the hole to see that it's close, my fine tuning is done by loosening timer set nut and rotating a couple degrees one way or the other while it's running until my ear tells me I'm in the sweet spot. Lock it down and burp the throttle a few times. Maybe tweak a little more if needed, but generally speaking I let my ears tell me when I've got it right, not the mark in the hole. Call me wrong if you want, but that's how I was taught.

[Excalibur]

John
Also note octane is measured differently around the world. If I recall correctly, your UK 95 is something like US 91? The important thing is to set timing to the balance of octane vs compression ratio.

The '48 -'57 manual permits a 3 degree variation of timing no doubt to suit the particular fuel used.

Doc37W, nice tip re wrapping tape around plastic plug (I must try that) and very nice summary of how to set timing! . My plug doesn't screw all the way in to the flywheel so I lean bike hard over to the right... works well enough.
I like to start out with an accurate setting ...maybe tweak from there.

One other thing: watch out for the salt&pepper look to the spark plug insulator caused by over advanced timing or lean mixture. It is tiny bits of aluminum pocked out of the piston crown from detonation. This condition will break piston rings or worse..

'48 -'57 manual extract..

[devon john]

With the timing mark at the right side of the hole, the ignition timing is MORE advanced.

Centering the mark RETARDS the ignition timing.

Think about it-when the mark is at the right side, it is moving toward the center-so it isn't there yet. So firing the plugs when the mark is at the right side of the hole fires them earlier.

that makes sense ,,,,, i was just passing on what a friend had suggested ,,, as you point out i think he's wrong

john

thinking again we are both wrong ,,,,,if it fires at the mark it before top dead so anything before is advance and that would be on the left of centre ,, so my mate was correct ,, on advance,,

[Excalibur]

This is the mark as per FL/FLH. Therefore center of the hole would be about 32°before top dead center.
TDC is further to the right as it has not yet come into view. Note the rotation arrow.

[devon john]

This is the mark as per FL/FLH. Therefore center of the hole would be about 32°before top dead center.
TDC is further to the right as it has not yet come into view. Note the rotation arrow.

yes so advance is the left of middle ,,, when its late and your haft asleep you don't think strait

john

[awander]

Hey, john:

It can be confusing.

Think of it this way:

-While the engine is running, the mark moves across the timing hole from Right to Left.

-This means that the further to the Left the mark is, the further along the pistons are in their travel.

-So, the further to the Right the mark is, the earlier the pistons are in their travel.

-Therefore, the further to the Right the mark is WHEN IT FIRES, the earlier you are in the pistons' travel WHEN IT FIRES,

-The earlier you are in the pistons' travel WHEN IT FIRES, the more Advanced the ignition timing is.

-As you change things so that the mark is further Left WHEN IT FIRES, this means that the ignition firing happens later in the pistons' travel, so the ignition timing is more Retarded.

[RooDog]

A little tid-bit of information: I have checked this with a degree wheel. The timing plug hole is 10 degrees wide..... RooDog

[awander]

This is the mark as per FL/FLH. Therefore center of the hole would be about 32°before top dead center.
TDC is further to the right as it has not yet come into view. Note the rotation arrow.

TDC would occur when the mark is further to the Left.