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Discussion Starter #4
No SDS, I know I'm reckless, from all my research no one has done any major damage, only reports of a smoother running bike. Also, I was hoping for some input sooner, since there is no reason not to at least check your TB's with or without the SDS. My idle stayed a a constant 1300rpm's regardless of my small adjustments.



FWIW, you can try these guys.

http://www.suzukipitstop.com/home/home.asp
 

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Chuck,

Small inputs on the air screws don't do any harm. If you pull the electrical plug on the ISC valve when the key is 'on' (before hitting starter button) you will freeze the position of the valve exactly in its mid position.

Just to see if it could be done, I sync'd the TB's in this position. It is not a perfect method, because I believe the actual 'step value' at this location is in the mid-70's (as opposed to the desired 60 step), but it sync'd up perfectly and rides great. I did have to adjust down (screws inward) from around 1,600 rpm to the proper 1,300 rpm before sync. If I find any issues in the middle of hot summer at higher altitudes, I'll adjust back to where I was and start over.

My 2 cents.
 

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Chuck,

Because it took around 1.5 turns inward on both screws to drop from 1,600 to 1,300, if you only moved a small amount (say, up to 1/8 to 1/4 turn per screw), you might not see any rpm drop. I don't recall what the dealer mode was doing to the ISC valve position.

Based on my measurements, dropping the RPM's from 1,600 to 1,300 is equivalent to about a .025" movement on the ISC valve (out of +/-.072" possible travel - up or down from physical mid-stroke).

My goal was to figure a way out to do the sync without any SDS. While I'm not there entirely, I think I've shown that the ISC system is not the big bad boogyman that some think it is :eek:.

I'd say you did good, Chuck.
 

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Discussion Starter #8 (Edited)
I completely agree, and thanks for all your pre-experimentation. I did have a conversation with a Suzuki tech who owns an 07 SV650 and he said I should be more concerned with tight valves. I also found many other Suzuki models have dealt with the problem the same way.
 

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Yes, I had an intake valve that was on the edge of tolerance (getting tight) with less than 4k miles on the bike. I'm glad I checked it and corrected it when I did.
 

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What if you performed the TBS at the RPM you get after disabling the ISC? This should in turn leave the "75" at the same RPM meaning that the "60" should stay at 1300rpm or so. This of course assumes that your bike is currently operating around "60" at normal idle. So, if your bike idles appropriately in all conditions, you are close enough to "60" to try this method. Any reason to not run the TBS at the higher RPM?
 

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What if you performed the TBS at the RPM you get after disabling the ISC? This should in turn leave the "75" at the same RPM meaning that the "60" should stay at 1300rpm or so. This of course assumes that your bike is currently operating around "60" at normal idle. So, if your bike idles appropriately in all conditions, you are close enough to "60" to try this method. Any reason to not run the TBS at the higher RPM?
Jason,

I had considered this, but figured there could be some other dynamics at play which could cause trouble. Instead, if you are comfortable (and curious), I would encourage you to loosen up the radiator and reach up to pull the ISC plug with ignition on (bike already warmed). Then start it up and report back with what rpm's you idle at. If it's close to 1,300, and if a large enough sample of wee owners achieve roughly 1,300 in the same manner, then I'd say the 'tentative' procedure of mine might have merit.

For what ever reason, mine idled at 1,600 with the plug pulled. I believe there are enough manufacturing tolerances to yield this much rpm variance, and that Suzuki designs their bikes ultimately for quickness through the service department (at the cost of performance drops, if necessary). Following the sync, it now idles at 1,300 with the plug pulled. Don't forget to clear the error code with the dealer plug after experimentation.

Disclaimer: Don't monkey around unless you feel sure of your actions ;)
 

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Also, something that just hit me. Is the 1600rpm the fast idle position? Does the valve default to this for a fixed period of time during warm up. Could you pull the plug for the valve after the bike as idleded down after the fast idle?
 

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Makes sense. How do you reset the error code in dealer mode?
Turning the ignition off and on does a reset unless the problem still exists. Fix the problem and the code goes away.
 

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Also, something that just hit me. Is the 1600rpm the fast idle position? Does the valve default to this for a fixed period of time during warm up. Could you pull the plug for the valve after the bike as idleded down after the fast idle?
That's a good question. I think the only problem with this is if your bike is not running optimally to begin with (which is partly why you'd be doing the sync anyway) then the location of the valve after pulling the plug on a warmed-up bike would be unkown. On the other hand, I would think that everyone's ISC will move to the same position when the ignition is turned "on", before starting the engine.

I'll admit to possibly being entirely off-base with my assumptions, so I would welcome other curious types like yourself to sort this out. I just know I'm never taking mine into the dealer:).

Let me know what you find out.

GW: Thanks for correcting me, for some reason I was thinking I had to jumper the dealer plug to clear it.
 

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I think we are getting close here...

I understand completely what you mean about pulling the ISC on a warm bike. If the bike is off of "60", then it will remain at that value. The idea behind the SDS is to set the valve to a known position and then tune in an idle rpm accordingly. We might be able to do exactly that if the position of the valve after pulling the plug pre-start is constant, and if we can determine what rpm is associated with that position. Let's assume that it represents the fast idle (1500-2000rpm). If that is the case, tweak the idle speed to match that, then restart the bike and pull the plug after warm (which should now be closer to "60") and perform the TBS. This will take almost all of the guess work out of the system. The only small errors will be a VERY slightly off center range ISC, which should only have problems at the end of the range i.e. hot or cold (when it runs out of room to adjust).

This assumes that the fixed position of the pulled plug ISC pre start is constant and for fast idle. :) Anyone know an exact rpm for fast idle?

I will have my bike apart this weekend and will try my best to confirm some of these theories.
 

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I think we are getting close here...

I understand completely what you mean about pulling the ISC on a warm bike. If the bike is off of "60", then it will remain at that value. The idea behind the SDS is to set the valve to a known position and then tune in an idle rpm accordingly. We might be able to do exactly that if the position of the valve after pulling the plug pre-start is constant, and if we can determine what rpm is associated with that position. Let's assume that it represents the fast idle (1500-2000rpm). If that is the case, tweak the idle speed to match that, then restart the bike and pull the plug after warm (which should now be closer to "60") and perform the TBS. This will take almost all of the guess work out of the system. The only small errors will be a VERY slightly off center range ISC, which should only have problems at the end of the range i.e. hot or cold (when it runs out of room to adjust).

This assumes that the fixed position of the pulled plug ISC pre start is constant and for fast idle. :) Anyone know an exact rpm for fast idle?

I will have my bike apart this weekend and will try my best to confirm some of these theories.

Jason,

Yes, you're filling in the gaps in my way of thinkin', and that's a bit spooky! :eek: See what you get for an rpm at idle after you pull the plug (pre-start). I know for a fact that the ISC is the controller of the fast idle function, I just don't know for sure if it goes to that position pre-start. If I were designing the software, I think it would make since for it to do so, in advance of start.

I think you are onto something.
 

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Any tips on how to gain access to the ISC plug? I have unbolted my radiator and moved it around.... but cannot gain access to the two or three plugs back up and behind it. What does the ISC plug look like by the way?
 

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I think we are getting close here...

We might be able to do exactly that if the position of the valve after pulling the plug pre-start is constant, and if we can determine what rpm is associated with that position. Let's assume that it represents the fast idle (1500-2000rpm). If that is the case, tweak the idle speed to match that, then restart the bike and pull the plug after warm (which should now be closer to "60") and perform the TBS.... Anyone know an exact rpm for fast idle?QUOTE]

Thinking about this some more, if your theory is correct, then every bike's ISC valve may move to a slightly different position (a 'learned' position) to achieve the 1,600-1,700 (or so) rpm at fast idle. So we MAY wind up back to square one, since the true valve position is not really known, only that everyone's fast idle rpm speed is about the same.

Some more background on my bike, so that you can think some more on it as you dive into yours:

I bought it with 923 miles on it (babied by first owner). I had around 4,000 miles on it when I did these tests and the TB sync. Prior to this I had just done a secondary throttle plate sync (front plate had been 'open' more than the rear by 1/32"), a TPS sync. and a valve adjust (returned all valve clearances to dead center of spec.). For the measurements on where the ISC valve was, I had a machinist friend make a duplicate piston plug from brass, with an adjustment screw on it to vary the stroke of it. When I used it and adjusted it inward until about 1,100 rpm's, the ISC went to full-open (I knew this because it was out in front where I could put calipers on it). Conversely, it went full closed when I adjusted the brass plug to achieve just over 1,300 rpm's. When I say 'full closed' or 'full open', what I mean is that the edge, or shoulder, of the valve's piston is either fully obscuring or fully revealing, the side ports in the ISC housing which lead to the TB's.
 

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I haven't had a chance to pull the radiator forward to get to the ISC plug. When I do, what does it look like? Also, does it help to remove the air box?

Also, it occurred to me that depending on the atmosphere where the TBS is being done, blanket setting the ISC valve to "60" wil not always give the widest range for the ISC. The ideal way to do this would be to have sensors measuring the density and temperature of the air and compensating this ISC value for the TBS. I am not entirely sure if the SDS has a software side that allows you to input these parameters, but that would certainly be convenient.

This sorta throws a wrench in the spokes (so to speak). Everything will be relative to the atmosphere at the time of synchronization. The only solution to this that I can imagine is to come up with a table for "75" - fast idle rpms based on barometric pressure and temperature. Then reset and pull the plug while running and we should now have a relative "60" that would give the ISC the greatest operating range.

This is only a problem when you consider the advantage that the ISC has given the 07+ bikes. Before the ISC, this procedure was always relative and likely caused problems for people travelling between altitudes. I suppose syncing the TBS with ISC at "60" while the temperature is moderate would be ideal and give you the widest range for your operating area at different temperatures, not neccessarily other elevations.
 
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