setting ignition timing on a iron sportster

[Kiwi]

has any body got details of how to statically set the ignition timing on a iron sporty

the only descernable mark on the flywheels is top dead centre for the rear cylinder

I have set up a degree wheel on the end of the crankshaft so I can actureately measure where the crank is

bike is twin plugged so the ignition will need to be retarded about 7 degrees

what is the normal advance required and is this with the ignition advanced (3000 plus rpm ) or retarded?

I have one of those alloy spanners for manually holding the cam in the advanced position

I don't need instructions about timing lights because a I havn't got one, and b the motor haqsn't been fired up yet and the primary drive is all dsiassembled so a timing light would be as much use as a chocolate teapot

[kevscrivener]

This may help, Graeme.

Setting The Ignition Timing on Your IronHead - The Sportster and Buell Motorcycle Forum

[the_french_owl]

Hi Kiwi,

Crank:

round dot = TDC on front cyl

vertical mark = TDC on rear = 45 deg advance (full advance) for the front. This is where you should time your standard engine.

With twin plugs, I don't think you can retard 7 deg. I use to run a 67 CH twin plugged, was most happy at 40 deg advance.

Patrick

[Kiwi]

Originally Posted by the_french_owl

Hi Kiwi,

round dot = TDC on front cyl

Patrick

Thanks Patrick, several round dots on flywheels just to confuse the issue,

Is the timing set in the fully advanced position?

[the_french_owl]

Depends if you have an auto advance mechanism... If yes, you'll need to lock it with a washer in the full advance position to set your timing with the degree wheel.

The dots/slash should normally appear in the following sequence when you rotate the engine anti-clock from the crank side:

- double dot: 45 deg advance for the back cylinder, rarely used

- vertical slash: 45 deg advance for front and TDC for back cyl

- single dot: TDC for front cyl

Your ignition cam: small lobe is front cylinder cam, wide lobe is back cylinder cam. Obviously, time the front with the small lobe...

Sometimes, depending on years, single and double dot are swapped...

Patrick

[Kiwi]

S&S flywheels have triple dot???

used dial gauge and worked off the rear top dead centre to get 40 degres advance for front cylinder

bloody starter relay and starter solenoid both F$%ked so when I get new ones fitted will see if it works

[Panhead Boris]

I have seen loads of complex ways of doing this that make my head hurt. I don't like anything that I can't replicate on the hard shoulder in case of need.

The way I use for later sporty's (i.e. not magneto) and alternator shovels was passed to me by an ol'-timer (even older skool than me!).

Having lined up crank timing mark on either cylinder, set adjusting holes on timing backplate with screws exactly centred at 12 o'clock and 6 o'clock....assumes that points are in reasonable condition and have plenty of meat on them.

I have never found any that would not start and run at this setting, to allow fine tuning by ear. Most that I have subsequently strobed have not required further adjustment! (I can name 3 current members whose bikes I did this on over the years, and they have never required further adjustment).