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I recently installed a full CS Racing Exhaust. Upon first fire up I didn’t install the DB killer in the bike but I noticed the idle going from 1000 to 1200 RPM. Almost like surging. The mods done to my bike are, CS Exhaust, “Air Box Mod”, Exhaust servo eliminated, Block off Plates Pair Valve and O2 sensor plugged. I sent my ECU back to Dano’s he was the one in originally did the soft tune when I first got the bike. After getting the ECU back it does the exact same thing Dano told me to install the DB killer to make it stop because these bikes are sensitive to exhaust back pressure. I’ve seen videos with people with no DB killer and it doesn’t have the lumpy idle. Does anybody else have this issue when they installed this exhaust or any full system?
 

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I recently installed a full CS Racing Exhaust. Upon first fire up I didn’t install the DB killer in the bike but I noticed the idle going from 1000 to 1200 RPM. Almost like surging. The mods done to my bike are, CS Exhaust, “Air Box Mod”, Exhaust servo eliminated, Block off Plates Pair Valve and O2 sensor plugged. I sent my ECU back to Dano’s he was the one in originally did the soft tune when I first got the bike. After getting the ECU back it does the exact same thing Dano told me to install the DB killer to make it stop because these bikes are sensitive to exhaust back pressure. I’ve seen videos with people with no DB killer and it doesn’t have the lumpy idle. Does anybody else have this issue when they installed this exhaust or any full system?
Yes same here with decat and Yoshi can but still with exhaust servo. dB killer makes the idle much smoother.
 

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Yes it's quite normal. Embrace the lumpy idle, wear it with pride.
 

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My bike is stock, and on startup it has a lumpy idle. Compared to a lot of bikes I’ve had I’d say it takes a while to warm up. That’s no doubt euro 4 emissions.
 

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On start up my bike sits at a high idle until warmed up, but no lumpiness. I have a Mivv double gun slip on. No ECU changes, no headers I've run it with and without DB killers and performance is exactly the same with absolutely no lumpy idle. Noise is louder without DB killers is all. I do get some lumpiness in the 2 to 2.5K region if I try to stay exactly there, but I never do that. :LOL:
 

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Is it a bad thing to have a lumpy idle that fluctuates all of 200 rpm?
 

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After installing my decat pipe I noticed a difference in the sound of the bike when idling, but it wasn't surging up and down. Just the normal fluctuations in RPM during idle were now more pronounced with the freer flowing exhaust and louder slip-on, whereas before with the stock exhaust, it was restricted/muffled enough that those minute fluctuations blended in with one another. Idle hasn't changed since swapping to an aftermarket header which does away with the exhaust valve.
 

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I recently installed a full CS Racing Exhaust. Upon first fire up I didn’t install the DB killer in the bike but I noticed the idle going from 1000 to 1200 RPM. Almost like surging. The mods done to my bike are, CS Exhaust, “Air Box Mod”, Exhaust servo eliminated, Block off Plates Pair Valve and O2 sensor plugged. I sent my ECU back to Dano’s he was the one in originally did the soft tune when I first got the bike. After getting the ECU back it does the exact same thing Dano told me to install the DB killer to make it stop because these bikes are sensitive to exhaust back pressure. I’ve seen videos with people with no DB killer and it doesn’t have the lumpy idle. Does anybody else have this issue when they installed this exhaust or any full system?
I have the lumpy idle as well but the bike judders at low rpms in first gear. Like between 10-17 mph and keeping rpms low (1500 to 2000). Do you also see the same?
 

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Have you had the bike tuned or flashed to help account for the changes?
I had my bike flash by 2w2d. I already sent the ECU to get it corrected for a second time but it still does it. I have lextek headers with stock muffler and bought an arrow muffler with baffle to see if that makes a difference. Any thoughts?
 

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I had my bike flash by 2w2d. I already sent the ECU to get it corrected for a second time but it still does it. I have lextek headers with stock muffler and bought an arrow muffler with baffle to see if that makes a difference. Any thoughts?
Did they say what changes they made to the flash when you sent it back? What year is your bike and how many miles are on it? It could be that your throttle bodies are way out of sync. Also, did you retain the oxygen sensor or has it been eliminated?

There's been others here who have dealt with the idle fluctuation after adding a full exhaust and it seems that most have cured it, or at least improved it, by either increasing the length of their slip-on (changing to a longer one) or installing a DB killer to increase backpressure in the exhaust. Although, if you had the poor idle even with the stock slip-on, I'm not sure this would help in your situation. The factory slip-on has what amounts to a DB killer built-in, hence the tiny little outlet, so I doubt the Arrow is going to change anything for you, unfortunately.

I have the same Lextek header. I was originally running an Akrapovic slip-on with no fluctuating idle. I just switched over to a Leo Vince slip-on, but kept the Akra on hand. The Leo Vince is the LV-10 model, which is a super stubby and ultra free-flowing little slip-on. Even with that, I have no idle issues.
 

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My bike is a 2018, 6000 miles. No oxygen sensor. There was a slight improvement on idle with the arrow but it is still there just less rough. It still goes up and down but sometimes it stays stable.

I have checked my header for leaks but there are none as i was told it could be that. The judder happens between 12-13 mph in 1st gear. People have mentioned spark plugs and now you mentioned the sync. I have the tops for both as well. However, will continue working with the tuner and see if they can figure it out.

I am pretty much regretting the mods.
 

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My bike is a 2018, 6000 miles. No oxygen sensor. There was a slight improvement on idle with the arrow but it is still there just less rough. It still goes up and down but sometimes it stays stable.

I have checked my header for leaks but there are none as i was told it could be that. The judder happens between 12-13 mph in 1st gear. People have mentioned spark plugs and now you mentioned the sync. I have the tops for both as well. However, will continue working with the tuner and see if they can figure it out.

I am pretty much regretting the mods.
I watched your video and saw the shuddering you mentioned. Are you sure you're not just lugging the bike down by creeping along at such low RPM?
 

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I watched your video and saw the shuddering you mentioned. Are you sure you're not just lugging the bike down by creeping along at such low RPM?
I am sure because that's the speed i get into my neighborhood and when it was stock i never experienced that. Also, my friend has a gsxs1000f 2016 and his bike is very smooth in comparison to mine at those rpms. His bike is stock. The bike runs pretty smooth from 0-11mph with the expected feel for low speed but as soon as I start giving it a bit of gas it does that until 15mph. It is somewhat abrupt. I put it on my pitbulll stands and can easily replicate it.
 

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I am sure because that's the speed i get into my neighborhood and when it was stock i never experienced that. Also, my friend has a gsxs1000f 2016 and his bike is very smooth in comparison to mine at those rpms. His bike is stock. The bike runs pretty smooth from 0-11mph with the expected feel for low speed but as soon as I start giving it a bit of gas it does that until 15mph. It is somewhat abrupt. I put it on my pitbulll stands and can easily replicate it.
I'm not sure what's going on then. I have a full exhaust and many other mods along with a Dano's flash, and this isn't something I've experienced. My bike had some low speed issues like that prior to the flash, but now it's ultra smooth all around. I have heard of some having issues with the 2WDW flash, but I can't say that's your problem for sure. Hope you can figure it out.
 

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I'm not sure what's going on then. I have a full exhaust and many other mods along with a Dano's flash, and this isn't something I've experienced. My bike had some low speed issues like that prior to the flash, but now it's ultra smooth all around. I have heard of some having issues with the 2WDW flash, but I can't say that's your problem for sure. Hope you can figure it out.
Judder went away after unblocking the pair valve/ it is back to smooth. It may still be there but not as noticeable.
 

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Judder went away after unblocking the pair valve/ it is back to smooth. It may still be there but not as noticeable.
@Dmvgsxs1000

Unblocking the PAIR valve fixed it? There's tens of thousands of Suzuki's with blocked PAIR valves running around every day without experiencing the shuddering at low speed/low RPM as your video depicted. Here's my opinion on what was likely the problem in your case.

The PAIR valve injects fresh air into the exhaust stream in an attempt to help eliminate any unburnt fuel from exiting the exhaust and entering the atmosphere. It doesn't have any impact on how the engine runs, as it's operation comes into play after combustion has taken place, not during.

How did you block it? Did you simply remove the single hose connecting the air box to the valve and cap each end, or did you remove the valve completely and install blockoff plates on the engine?

Either way, there's only one way I can see the problem you were experiencing as being caused by having the PAIR blocked and then resolved by unblocking it. My guess is that you either blocked it off improperly altogether, or you did it properly, but had a vacuum leak at one of the ports. If this was the case, undoing your work and reverting back to stock and seeing the issue resolved would make it seem as if the block-off itself caused the problem, when in fact it was just a leak somewhere.

A vacuum leak will exhibit the lumpy idle and poor performance at low RPM, which are the two issues you described.
 

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I'm not sure what's going on then. I have a full exhaust and many other mods along with a Dano's flash, and this isn't something I've experienced. My bike had some low speed issues like that prior to the flash, but now it's ultra smooth all around. I have heard of some having issues with the 2WDW flash, but I can't say that's your problem for sure. Hope you can figure it out.
I did not use the plates. I blocked it putting a rubber cap in the line to seal it. Similar to how people use the marble. The cap blocked it fully as an there was no exhaust backfire at all. Not that it is unblocked there is the characteristic sound in the exhaust that comes up when the pair valve is doing it's job. The tuner told me just to unblock it and it will become smoother at the expense of some peeformance. It actually did exactly what he said so i do not think it was blocked incorrectly, i guess this is something expected with their flash. He knew the exact result i would get. I may try a different flash because i really want the pair valve to be blocked. I don't like the sound it know makes during deceleration.

The tuner also told me they make no changes in the mapping between 1500rpm - 2000rpm so i had no other option than unblocking the pair valve and it worked.
 

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I did not use the plates. I blocked it putting a rubber cap in the line to seal it. Similar to how people use the marble. The cap blocked it fully as an there was no exhaust backfire at all. Not that it is unblocked there is the characteristic sound in the exhaust that comes up when the pair valve is doing it's job. The tuner told me just to unblock it and it will become smoother at the expense of some peeformance. It actually did exactly what he said so i do not think it was blocked incorrectly, i guess this is something expected with their flash. He knew the exact result i would get. I may try a different flash because i really want the pair valve to be blocked. I don't like the sound it know makes during deceleration.

The tuner also told me they make no changes in the mapping between 1500rpm - 2000rpm so i had no other option than unblocking the pair valve and it worked.
I replied in the other thread. No sense going back and forth between both.
 
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