Test rode a 2000 Interstate found smooth throttle response.

[Quicksilver]

I have a 1997 standard. I find there is a lag when I get on the throttle. Everything else seems great, easy start, runs good, smooth, once I get the bike going she just wants to keep on accelerating.   When I tested the 2000 Interstate I found the throttle has a more immediate response. I'm wondering if it's the ICM. If it can be improved with this mod, where is the ICM located and can I just plug and play using a 2000 Interste icm?

[GJS]

The ICM is behind the right side cover and yes it is a plug and play replacement.You may also want to invest in the interstate carb springs, I hear they are primarily responsible for the smooth acceleration, but I do not know this for sure.

I'm sure others will chime in here.

Cheers,

Glenn

[JC]

I switched to the interstate springs on my 97 Tourer, and felt a noticeable difference, even more when I added an interstate ICM. Yes, the ICM is plug and play. I watched eBay and ended up getting the ICM for about $80, but they seem to go a bit higher now.

[Jess from VA]

After Big BF went thru my bikes (tune, valves, desmog, petcock rebuild, all new intake orings, carb synch) throttle response on both is better than I can ever remember.  It can be any, all or some of these things.  My bikes both ran fine before the work, any degradation is so slow and gradual over time you simply never notice, bikes and parts are aging that's all.

I doubt a new ignition would do it, alone.  I certainly could be wrong.

[Thunderbolt]

Pilot jet adjustment might help and carb sync.  It is under the left side cover if memory serves me correctly.

[98valk]

look at the advance curves btwn both. I/S much better overall.

http://timskelton.com/valkyrie/tech/trigger_wheel_plus_dyna3000.ht
m

[Black Dog]

I too have a '97 Standard, and I am running an I/S ICM.  The 'get up n go' factor is much improved, but the 'lag' you mention could be due to a bit of slack in the throttle cable(s).  See how much twist/rotation you get when just sitting at idle, to bring the RPM's up (shouldn't be much).  The tension of the cable is adjustable right at the housing.

Might be worth a look see.

Black Dog

[Gary]

It is under the left side cover if memory serves me correctly.

[doubletee]

Just to be a contrarian  - I put I/S springs on my Standard and I can't tell any difference from the originals. Maybe the previous owner had already installed I/S springs and I didn't know it. If that's the case, there's a good reason I didn't notice any difference. 

[Patrick]

I'd have to say that there is a problem somewhere.. There should not be an acceleration lag..
 The IS ICM has a bit more advance during mid engine speeds and the IS carburetor springs are heavier/stronger than the standards/tour to slow the acceleration[ lean spot] just a bit to help avoid a lag due to the extra weight..

[98valk]

I'd have to say that there is a problem somewhere.. There should not be an acceleration lag..
 The IS ICM has a bit more advance during mid engine speeds and the IS carburetor springs are heavier/stronger than the standards/tour to slow the acceleration[ lean spot] just a bit to help avoid a lag due to the extra weight..

u have that backwards. the I/S springs are softer, which allow the slides to move up faster, allowing more fuel in sooner. they sort of work like an accelerator pump does in a holley carb. this is what gets rid of the lag.

[Patrick]

Thats what most think.. Measure them..

[Quicksilver]

Well I prefer to try the easy stuff first, I just bought a used control module for 200$ for a 2000 interstate, expect it next week, I'll get back to you with the results.
Thanks for the info.
Dann

[98valk]

Thats what most think.. Measure them..

I have both, u have it backwards.

STEP SIX (alternate): Using Interstate springs on a Standard
Many folks have had success by changing to Interstate springs from the Standard kind. This enhances throttle response in the mid range. IS springs are shorter but with more coils. Used in conjunction with shims or new needles, this makes for a nice mod for only about $12.
also compar pic of springs
http://www.rattlebars.com/mtz/shims.html

[Ricky-D]

Regardless of the bike model the reaction of the motor to the throttle should be constant.

CV carburetors are designed to facilitate the smooth reaction.

When you modify the air pump flow through the motor you change the air/fuel mixture and affect the responsiveness to the throttle.

With the Valkyrie, normally,  modifications to the flow will cause a degradation to the responsiveness of the motor to the throttle.

I know! Not something you really want to hear (read).

***

[sugerbear]

this may be just fartin in the breeze, but, have you checked the rubber "bumpers"
in the rear wheel. if they are real loose it could give the feeling of a lag.
probably WAY off here.

and the slack in the throttle cable?

[Quicksilver]

So you are suggesting that changing the springs is not reccomended? Do you think changing the ICM will result in any significant change to throttle response? I have recently replaced the rubbers in the rear wheel, they were worn and it did improve the feeling of looseness in the drive train when upshifting. I can still do the nickel trick and find no slack in the throttle cable when reving the motor for that.

[Patrick]

As I mentioned,, there must be something wrong.. It should not hesitate if everything is as it should be..
I don't believe the IS ICM does anything different at low engine speeds.. Different diaphragm springs shouldn't do much at low engine speeds[ I can't tell any difference at any speed].. I would suggest finding the problem rather than throwing parts at the problem..

[Westsider]

"once I get the bike going she just wants to keep on accelerating"

Yep, it's been described here before as " turbine like" ,I agree, and best decription I have heard of.

edit; I don't think you will find two bikes (same models) that ride and run "EXACTLY"  alike, no matter what you do , close , yea, just saying and all that.

[Quicksilver]

Perhaps I could describe the problem better by saying that when accelerating to pass another vehicle and getting on the throttle, the acceleration is not immediate, just builds. Hesitate may not be the right word.
It does get there but not as quickly as I'd like. This is without down shifting. Likely that would make her jump faster, however I find the bike has so much pulling power that I rarely downshift when passing. I just give her more throttle. Perhaps this is normal.

[Michvalk]

There is a difference between the Interstate and the standard in the carb springs and the icm. Maybe changing the two things will give you the response you are looking for. Maybe you just need an Interstate!

[Ricky-D]

Perhaps I could describe the problem better by saying that when accelerating to pass another vehicle and getting on the throttle, the acceleration is not immediate, just builds. Hesitate may not be the right word.
It does get there but not as quickly as I'd like. This is without down shifting. Likely that would make her jump faster, however I find the bike has so much pulling power that I rarely downshift when passing. I just give her more throttle. Perhaps this is normal.

CV carburetors are what is happening with your bike. You can Google it and learn more about them and how they affect your bikes performance.

Smooth is where it's at.  The only upgrade would be fuel injection.

With old style carburetors there's always a hesitation and they have accelerator pumps to help with that particular shortcoming.

Harley puts accelerator pumps on their CV carburetors but I don't think they're needed and you would definitely use more gas if the Valkyrie had accelerator pumps on all the carburetors.

Of course there can be a lag when you hit the throttle full "on". The butterfly valve opens with the throttle but the slide (which is actually doing the metering) is controlled by the vacuum developed, so it rises slowly and at it's own rate.

If you actually wanted to mess with the carburetors attempting to get the reaction time quicker I'd suggest to open up the holes in the vacuum passage which will allow the slides to raise quicker.

***

[PatrickDoss]

Perhaps I could describe the problem better by saying that when accelerating to pass another vehicle and getting on the throttle, the acceleration is not immediate, just builds. Hesitate may not be the right word.
It does get there but not as quickly as I'd like. This is without down shifting. Likely that would make her jump faster, however I find the bike has so much pulling power that I rarely downshift when passing. I just give her more throttle. Perhaps this is normal.

If you're not downshifting, you're relying on the power that's available at cruising speed. One difference between a Std. and Int. that might make for better response is the Int. has a different cam profile which makes more mid-range (cruising speed) torque at the cost of maximum horsepower at high RPM.

[Dirty Dave]

Having used my friends I/S quite a bit, I was surprised my 97 Std throttle response was not as "crisp". I wanted immediate throttle response but it felt more like a Triumph Rocket 3. I wanted that Ferrari response. The I/S spring mod made a world of difference. I later changed out the ICU as well
which (don't laugh) changed the exhaust note. Seemed to have a bit more vroom.

I personally find the I/S too heavy. Ride naked!

[98valk]

If you're not downshifting, you're relying on the power that's available at cruising speed. One difference between a Std. and Int. that might make for better response is the Int. has a different cam profile which makes more mid-range (cruising speed) torque at the cost of maximum horsepower at high RPM.
[/quote]

incorrect
per tech manual;
all california bikes all yrs have the same cams
all 49 state bikes all yrs have the same cams.
some magazines have stated that all '98s have the calif cams, there has been much disagreement on this though.
calif cams make better mpg less HP
49 state make better HP less mpg.
tech manual list actual cam specs.

[Quicksilver]

An update: Installed the module today and took it for a spin. Found the improvement if any was marginal with regard to my desire for quicker throttle response. Looks like the CV carb is the limiter here. Thanks for all the advice.
Dann

[MP]

Perhaps I could describe the problem better by saying that when accelerating to pass another vehicle and getting on the throttle, the acceleration is not immediate, just builds. Hesitate may not be the right word.
It does get there but not as quickly as I'd like. This is without down shifting. Likely that would make her jump faster, however I find the bike has so much pulling power that I rarely downshift when passing. I just give her more throttle. Perhaps this is normal.

Not sure what initial speed is, but sounds to me like you need to downshift!  If I am at 55-60, and open the throttle in fifth, it will kind of build speed.  If I drop a gear or two, it will whip around the car.  I think you are asking too much of 5th gear, which is good for 120 mph top end, to be able to crisply accelerate at 60 mph!

MP

[Quicksilver]

Yes, it will go like a scalded dog if I drop a gear. I was just comparing the throttle response of my 97 standard to what I felt when riding the Interstate. The acceleration is there but as you say it takes a bit to build. The Interstate icm does make a bit of a difference but I can't say if it's better in the long run. I was out a bit this morning, the acceleration is good, perhaps more consistent over a wider range of rpm and speed. I can't say I'd recommend the change if your origional is working.

[Ricky-D]

You may find a trigger wheel will help out the way you wish.

***

[Misfit]

When was the last time you synchronized your carbs? That allows the same amount of vacume to each carb. Vacume is what raises the needle. If the carbs are not balanced you will not have the smooth acceleration that you are looking for.

[Quicksilver]

I've never touched the carbs, and I'm fairly certain the 2 previous owners didn't either. Right now I have 130000 Km on the bike. I bought it with 65000 4 seasons ago. She runs fine and I really wasn't complaining until I tried that Interstate. I hesitate to take it to the dealer for anything, bad experience with them and would prefer to do things myself if possible. I've looked at the different setups for synchronizing and figure it's better to leave it if it ain't broke. Around here getting work done by someone who knows what they are doing is a bit difficult.
I haven't found a competent mechanic I can trust to work on it yet. So I've been reading the various posts and problems trying to maintain it myself without breaking anything. So far thanks to you guys she works just fine and I'm confident going down the road. If syncing the carbs is advisable I'll take a crack at it. Are there any other symptoms that would point to that as being necessary?

[GJS]

I'd think you might hear some poping or very mild backfiring, especially on deceleration, if the carbs were significantly out of sync.
But then again poorly set valves may do that too.

Good luck.

GJS

[Ricky-D]

If it's running fine as you say I would suggest to do nothing and simply add some fuel additive to the gas every now and then to keep it the same.

***