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Discussion Starter #1
OK I have a 07 SM610 with 3 miles on it ... lol
I have all the smog stuff off and thats it , but I have this bad hesitation un less I give it a little gas or back off a little ... any ideas ?
I have another plug coming ... will that help ?
 

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Iridium plug and rejetting the carb will make it run like a whole different bike. They come jetted way too lean from the factory to pass emissions.
 

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Iridium plug and rejetting the carb will make it run like a whole different bike. They come jetted way too lean from the factory to pass emissions.
I had the stutter problem before and after all the mentioned fixes including JD jet kit, plugs, gas, and etc. About 7k later my bike still has the stutter. It comes and goes with the weather.
 

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Isn't the 07 610 fuel injected..? Because if it is, there's no way to rejet it of course.
 

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Not in North America.

The plug, re-jetting and for some disconnecting the TPS is the cure. I've done the first 2 (TPS made no difference) and have the "stutter" down to nothing more then "character". :)

Isn't the 07 610 fuel injected..? Because if it is, there's no way to rejet it of course.
 

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Mine will stutter very rarely [3-4 times in 200 miles so far], but even then, its just a small little hiccup that really doesnt upset the bike a whole lot. It happens during long periods od sustained throttle at the same amount of throttle. Im gonna get one of the Iridium plugs everyone talks about and rejet it a bit and see what lies in store for me :)
 

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I ran the JD red needle 5th clip for most of the summer, and occasionally I had the unbearable days where the bike felt like someone was pulling on the seat while stuttering. When the weather here, maryland, got cold the stutter returned on a pretty consistent basis with a varying degree of severity.

I originally thought it was the gas in my area. I had exchanged pm's with MikeB who lives in the same locale, and he went so far as to buy some VP gas for his track days to cure the issue. No luck, and so much for my gas quality idea.

Then I thought it was humidity, but on some days when humid the bike ran okay. The problem just seemed to come and go.

Anyways, late fall I turned into a jetting fiend. I tried all the JD kit combos and some needles from Sudco. Sudco actually was aware of the problem, and said so were all the manufacturers KTM etc with FCR carbs. I had a mix bag of results changing the jetting around, and never really completely resolved the issue.

So what really is the issue? After changing the jetting and having the bike run great one day, thinking I resolved the issue, and having it run like crap the next day, I took off the air filter and air boot and duplicated the stutter while looking into the backside of the carb with a flashlight and mirror. I had reached the height anal retentiveness, but I wanted answers. Here is what I saw, gas at a constant throttle gurgles up the emulsion tube occasionally and goes down the intake in a smallish blob causing the hiccup, maybe. Why does it happen on some days and not the others? I thought that it was some temporal condition like humidity, and I think that is still a contributing factor, but I believe it is barometric pressure. When the barometer hits 30.3 I can here a slight hiccup in the motors engine, and when it falls into 29's my bike becomes miserable and feels like someone is pulling on the seat and making noises like its going to run out of gas. I could be wrong about the gas gurgling up the emulsion tube on the carb, but I am pretty sure about the barometer thing. At least on my bike. My doubts about the gas gurgle is that the motor accepts the stream from the AC pump.

I've set float heights, opened up the airbox, and adjusted the TPS with no luck. Running a needle in the third position seemed to keep things under control the best. Some needles aren't meant to be run in the third position, so caveat emptor. I am going to try some different needles that may work in second position, but I am really lacking motivation at the moment. My current needle EMM 3rd clip seems to tame the stutter, but it is kind of rich with a 180 main.
 

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Discussion Starter #9
JD kit installed

OK I put the JD jetting in and I LOVE the engine now but the shudder is now even worst !! I will try the plug by this week and keep you posted.
Has anyone ever tried a Power Now kit on there bikes . Seems to me that may help
 

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TPS is the Throttle Position Sensor. There is a sensor mounted on the left side of the carb with a plug attached to it. It can be adjusted if you have a torx security bit set and an ohm meter. I've adjusted mine and didn't notice anything remarkable, the same with unplugging it. Unplugging it is such a simple thing, so give it a shot.
 

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1/4 stutter

Did you enable the accelerator pump? There is a little cap that keeps the AP from squirting, it lives behind the plastic cover on the carb.
EPA wants it disabled. That would definitely cause the stutter down that low in the throttle position.
Good luck.
 

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Discussion Starter #16
Well I don't really know what I did but it seems to have almost gone !!
I took apart everything and put it back and now for today !! its better
 

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Well I don't really know what I did but it seems to have almost gone !!
I took apart everything and put it back and now for today !! its better
I hate when that happens! Yeah good that it runs nice....but :wtf:...I wanna know what the problem was/is and get it fixed for sure.:)
 

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Discussion Starter #18
I think the choke wasn't going in all the way. It was playing with it and I whacked it with a little hammer and it went in farther than it did at the start ... Who says you can't fix things with a butt kicking lol
 

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on my bike, the steady throttle hesitation is from a rich condition. I played with a lot of jetting combinations (using what came with the JD kit). Ended up with red needle 6th position, but with a 42 pilot (which is way leaner than stock). I think with many jetting combos you will find that if you lean the pilot and needle circuit, the stuttering will go away but the trick is to find the combo that cleans it up without taking away power and response
 
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