I/S ICM questions

[Momz]

OK, I've put the I/S carb springs and the ICM into my 98 Rat Rod.

But my question is about the ICM. Does it just change the advance curve to increase low and mid range torque, then back down at higher RPMs?
Or does the curve differ completley until the rev limiter kicks in?

I've not tried to find the top speed when the motor was unmodified and I'm not quite ready to find out this year (still healing). If someone could give me a definate answer, it would be greatly appreciated.

Thank you, Momz

[Trynt]

 Does it just change the advance curve to increase low and mid range torque, then back down at higher RPMs?

Yes.

[PhredValk]

My understanding is that the normal ICM advances the timing while the bike is cold, for a little more power and stability; and only does this up to 3500 RPM then returns the timing to normal. The Mod just bypasses the temp sensor so it functions at all temps. Advanced timing for more power at lower RPMs without changing the power and mileage at higher revs.
Fred.

[Patrick]

Its my understanding the IS ICM adds a few extra degrees of advance during low-mid engine speeds and flattens out at high engine speed to equal that of the STD unit.. The base and total advance is the same in either model ICM.. These critters do like more than 27 total degrees..

[quexpress]

Its my understanding the IS ICM adds a few extra degrees of advance during low-mid engine speeds and flattens out at high engine speed to equal that of the STD unit.. The base and total advance is the same in either model ICM.. These critters do like more than 27 total degrees..

They certainly do Patrick!  How have you been? Is the weather collaborating at your end? It certainly isn't here!

Posted by our friend Airetime a "few years ago" on the old tech board:

I/S ICM Advantage
If you run a Standard with OE wheel and I/S Carb Springs and a I/S ICM it runs like a stock I/S but doesn't have the extra 100 pounds that it was programmed to carry. Add that up and you will have a faster Standard! Now because it thinks that it is now a stock I/S, it runs like one only faster because it doesn't have the weight. You can advance it by 4 degrees if you want even more out of the mid-range and a bit more in mileage if you want to but isn't required.

Pricewise:
Used = About $150.00 (if you can find them)
New = About $225 - $235 (depends where you go)
Grin Factor = 8?

Take a look at the math here. If you install just the ICM unit, you are advancing it by programming 2 degrees advance through that 1800 – 4500 RPM range only. You don’t lose your top end. A timing wheel that has a 6-degree advance has that advance from start to finish or from 900 RPMs to red line. Because they have a fixed advance all the way through, but they lose top end. By adding another 4 degrees through modifying the timing wheel, you will benefit by not only the I/S ICM programming, but also the fixed additional 4-degree advance. You will have the 4 degree advance in the lower RPMS 900 - 1800 RPMS, full 6 degree advance in the 1800 - 4500 Mid range RPMS and back to a 4 degree above 4500 RPMS. Because the mod of only using an advance of a fixed 6-degree is all the way through, those will run rougher, usually demand high octane and reduce the top end more than you. I ran my Tourer with a fixed 4-degree advance before I got the I/S ICM and I noticed that it ran a little rougher and I had to run the high-test fuel. Once I added the I/S ICM unit it smoothed it out and gave me the low end, mid range and top end that I wanted. You will have an advantage if you combine the both.
Posted By: Airetime VSSS
Date: 12/26/2005 at 13:23:04

Many of us are set up that way ... and like it very much! It is certainly trouble free! 

[Patrick]

Normand,, hey there friend.. The weather has been great here for the past couple days,, good ole upstate NY fall weather.. 60-70F with a little breeze,sunny, beautiful.. The trees are starting to color up and I'm blowing leaves already.. We'll be heading to Key West soon, we're going for the first time to Fantasy Fest, its the craziest week of the year in a crazy town.. We'll be going to Key West for the rest of the winter just after Christmas and a friend from Boston is talking about us riding the bikes down together..Pheew, that ought to be a cold AZZ ride..

[98valk]

advance curves are different up to approx 4200 rpms, then they are the same.

see advance curves from dyna here

http://timskelton.com/valkyrie/tech/trigger_wheel_plus_dyna3000.htm

just remember dyna never made the I/S specific icm as shown.

[Momz]

Thank you all for your responses.

My Rat Rod Valk has the I/S carb springs and the I/S ICM, plus the "simple" ECT Modification. I just wanted to confirm what I believed to make my bike a "bit more fun" during the normal speed ranges that I like to ride at. My bike is also far lighter than when I bought it and I'm constantly looking where I can drill more holes and/or remove more weight.

I wanted to make modifications so that I could hunt down and pass every HD in my line of sight (just a sickness,...I know).

I heard a rumor that HD has suspended production of the V-Rod. And that the 2011s were assembled from the remaining parts when production ceased. Can any one confirm that rumor?

[quexpress]

Normand,, hey there friend.. The weather has been great here for the past couple days,, good ole upstate NY fall weather.. 60-70F with a little breeze,sunny, beautiful.. The trees are starting to color up and I'm blowing leaves already.. We'll be heading to Key West soon, we're going for the first time to Fantasy Fest, its the craziest week of the year in a crazy town.. We'll be going to Key West for the rest of the winter just after Christmas and a friend from Boston is talking about us riding the bikes down together..Pheew, that ought to be a cold AZZ ride..

You're having way too much fun Patrick! Good for you!!! 

[John U.]

My Rat Rod Valk has the I/S carb springs and the I/S ICM, plus the "simple" ECT Modification.

Momz, I think you (and I) have the perfect setup with the ECT mod and the I/S ICM.
No hard starting, no reduction in top end, just more advance when the engine can use it.
Only difference is I use the Potentiometer. Funny thing is I have that setup on two bikes, but the installation on the I/S has less advance range. I don't know if the difference is with the potentiometers or a mistake I made installing one of them.
It doesn't make enough of a difference to bother trying to figure it out.