Ironhead Broke Down and Ordered an Ultima Ignition Kit

[Jeff]

Originally Posted by Iron Mike

Another one off topic. And actually the first question I had for the forum on my very first visit.

Does anyone know the number of revs generally achieved on an Ironhead on an average healthy kick?
Perhaps if someone is in there with their programmer, can you dial in the dead revs and see where it starts and where it doesn’t? Perhaps set at two revs, attempt start, bump to 3 revs, attempt to start ect ect and see where it falls off?
Thanks

I always assumed all we get is one compression stroke per kick. Use the kicker to get one up on compression, then drive it down through that with authority. I've never felt a kicker go through another compression "bump" on its way down.

Interesting question, though. Do we actually get more than one? My guess is we don't.

[Ferrous Head]

Considering all of what's been said here I would probably suggest to anyone wanting to buy an Ultima kit that they buy/make a cable at the same time.

[needspeed]

Originally Posted by Iron Mike

.Does anyone know the number of revs generally achieved on an Ironhead on an average healthy kick?

Originally Posted by Jeff

I always assumed all we get is one compression stroke per kick. Use the kicker to get one up on compression, then drive it down through that with authority. I've never felt a kicker go through another compression "bump" on its way down.

Interesting question, though. Do we actually get more than one? My guess is we don't.

I think that's about right.

The 59 tooth clutch drum turns the 34 tooth motor sprocket, so one turn of the clutch drum would turn the crank about 1-3/4 revolutions.

The ratchet gear turns the clutch drum at a 1:1 relationship and the starter crank gear can turn the ratchet gear no more than 1/2 turn.

So based on the gearing of the system, pushing slowly on the kick pedal gets you no more than 1/2 turn of the clutch drum and roughly a 7/8 crankshaft revolution.

This doesn't take into account momentum of the flywheels from the speed of a healthy kick but it's unlikely that that would push it past the next compression stroke.

So I doubt you will get much more than one rev per kick.

(I don't think that verifying if the ignition has dead revs or not is off topic. In fact isn't that what we're talking about?)

[Ferrous Head]

Originally Posted by Iron Mike

Another one off topic. And actually the first question I had for the forum on my very first visit.

Does anyone know the number of revs generally achieved on an Ironhead on an average healthy kick?
Perhaps if someone is in there with their programmer, can you dial in the dead revs and see where it starts and where it doesn’t? Perhaps set at two revs, attempt start, bump to 3 revs, attempt to start ect ect and see where it falls off?
Thanks

When I first went to Methanol for my sidecar I discovered no one made a set of starting rollers that would handle it. Even Pin gal told me, not for V-Twins on fuel.

Nothing for it but to build my own. As part of that I needed to know how fast the engine needs to be going for it ti start. Sounds like an obvious, basic fact almost everyone would know. Spent quite a long time looking for the answer as it turns out. You'd think auto electricians would know. They don't.

Finally found it in a 1947 Packard FSM.

Turns out 400 rpm is the number.

I can sit on my bike and watch the tacho as it fires and it is indeed somewhere" around 400 that the fire is lit.

When your kicking it of course it is only necessary that the speed of the kick is 400 for a short space of time

[Jeff]

Originally Posted by needspeed

I think that's about right.

The 59 tooth clutch drum turns the 34 tooth motor sprocket, so one turn of the clutch drum would turn the crank about 1-3/4 revolutions.

The ratchet gear turns the clutch drum at a 1:1 relationship and the starter crank gear can turn the ratchet gear no more than 1/2 turn.

So based on the gearing of the system, pushing slowly on the kick pedal gets you no more than 1/2 turn of the clutch drum and roughly a 7/8 crankshaft revolution.

This doesn't take into account momentum of the flywheels from the speed of a healthy kick but it's unlikely that that would push it past the next compression stroke.

So I doubt you will get much more than one rev per kick.

Pretty sure you are right.

Originally Posted by needspeed

(I don't think that verifying if the ignition has dead revs or not is off topic. In fact isn't that what we're talking about?)

Oh no, I'm sorry, that's not what I meant. Verifying whether or not the module is programmed for dead revs is exactly what we have been talking about. Trying to figure out how many revolutions of the crank we get by kicking is what I meant is a bit "off topic".

Seems like we've figured that one out now as well. I think we all kinda knew the answer, but seeing the numbers explained helps visualize what's happening in there when we kick 'em over.

Pretty clear we wouldn't have a snowball's chance if it was programmed with three dead revs.

[Jerrys77]

You will be happy with the electronic ignition. Personally went thru 3 dyna ignition, sheared bolt destroyed advance units. Bought a s&s unit, uses a 80's tin cup timing trigger. No more broke on side of the road. I believe the advance weight is too heavy for the roll pin and gets out of balance shearing the bolt off.pulled my hair out for years with this problem. Also check shaft endplay bushing might be worn.
Glad I'm not the only person to have it happen to.

[The Doctor71]

FWIW..... using my non-scientific method of video taping the circuit breaker cam on my '71 xlch 900 motor and using the 225 lbs in this old body..... I can report I saw:

• approx 2 3/4 revolutions with the spark plugs removed
• almost exactly 2 revolutions with spark plugs installed

More or less, this equates to one compression stroke per cylinder per kick (at least on my bike).

FYI..... I define "revolutions" as flywheel revolutions, NOT circuit breaker cam revolutons. To get flywheel revolutions, I multiplied circuit breaker cam revolutions x 2.

If you give me a couple of hours, I'll attempt to put up a couple of youtube videos of what I took. aka so you can see what I saw.

EDIT: took me a little longer than anticipated to get some decent videos. But here it is:
I put these videos together in an attempt to answer the question..... how many revolutions can be expected with 1 kick.

I suggest you view on YouTube and set your playback speed to 0.25. Set Full Screen mode if you wish.

This video is WITHOUT spark plugs installed. The kick starts about the 9 sec mark. Achieved about 2.75 revolutions. aka just under 3.

This video is WITH spark plugs installed. The kick starts about the 4 sec mark. Achieved 2 revolutions.

[Iron Mike]

Thank you Doc

[IXL2Relax]

Originally Posted by Jeff

Pretty clear we wouldn't have a snowball's chance if it was programmed with three dead revs.

I wonder what constitutes their count window. If you continue to kick several times the engine does eventually make 3 revs.

With the module powered on, does it simply look for 3 revolutions since the power was applied, no matter how long it takes to make those 3 revolutions?

Or is there some window of time in which the 3 revolutions need to occur before the module resets the count to 0 and then looks for 3 revs?

And don't forget it supposedly has a 'soft off' function (preventing the module from grounding the coil) to prevent the ignition coil from oversaturation. It's said to occur when the engine is too long in the 'just before TDC' on the compression stroke. The red light on the module would be ON during this time of 'dwell', just before the timed spark.

I wonder if that 'soft off' condition remains until power is cycled off-on? Or, whether any rotatation of the engine gets the module out of the 'soft off' condition and back to normal operation?

The Cave of Wonder continues to wind this way & that, getting deeper & deeper...

So don't lose 'Matt's Phone Number' because you may need his help in getting back out of the Cave...

IXL _______ >>>> My Motorcycle Chronicles Are Here <<<<
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[Jeff]

One thing I have noticed is that it now has a greater tendency to kick back as I'm trying to find that sweet spot on compression before I really let it have it. It must be more advanced at idle than it was with the Dyna S and the stock advance weights. I timed that setup at full advance through the timing window on the left side, and just let the idle timing fall where it may. I have yet to dynamic time the Ultima setup. It just runs so well at their static timing position that I see no reason to mess with it. But it is "painfully" obvious that it's throwing a spark just as soon as I turn the ignition switch on.