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Re:coughing just off idle
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TOPIC: Re:coughing just off idle
#850090
Rocketman (User)
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coughing just off idle 3 Years, 1 Month ago  
Hello guys; I have a 2006 Road Star 1700 that I put exhaust on and a BAK, Dyna 3000, ported intake, Barons jet kit with 167.5 main jet, a Dyno Jet 37.5 pilot needle, PMS 1 turn, idle at 910, Barons needle on the 4th groove. The bike runs 100% better than before I did all the performance mods, and it is perfect with one hiccup or cough so to speak. When I come to a 90 degree turn (like a city street corner) and make the turn and get back on the gas the bike will cough. Or sometime when I am starting from a dead stop it will cough. This is intermittent doesn't do it every time and usually only after is full y warmed up. There is no popping through the exhaust at all, and other than this the bike is running great. When I blip the throttle it does not cough, and I have looked at the squirt when I blip the throttle and it looks like it is squirting when the throttle blade starts to open, but it is kind of hard to tell when the bike is running, can this be checked when the motor is off? My question is do you think it might the accelerator pump timing and or duration? or maybe the needle needs to be moved up a groove (3rd)? if it's the pump I haven't seen how to adjust the timing screw. I have seen that most people swap the nut on the Duration screw to the bottom side of the bracket and adjust the screw all the way down to get the least amount of duration they can. But I haven't seen anything on the timing screw. Thank you for any advise or input you guys might give.
 
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Last Edit: 2015/01/16 15:46 By Rocketman.
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#850095
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Re:coughing just off idle 3 Years, 1 Month ago  
If you have a Barons kit and a 1700R* you are way lean on the main jet. The 167.5 is the size for a 1600 R*. Step it up to a 172.5 main jet either the 37.5 or even a #40 pilot jet and start with the mixture screw at
2 - 2 1/2 turns out. Turning out adds fuel not air on the OEM carb see what happens with this setting and I'll bet your issues will be resolved.
 
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#850098
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Re:coughing just off idle 3 Years, 1 Month ago  
DBL post Sorry
 
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Last Edit: 2015/01/16 10:02 By davej.
 
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#850099
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Re:coughing just off idle 3 Years, 1 Month ago  
If your running a 167.5 mikuni main, I'd step that to a 172.5 mikuni main for the 1700. Back the PMS out, to about 2, to 2 1/4, and try that. You can also bump the pilot to a 40 mikuni, if you want.

I didn't like the way it ran, with the nut under the arm on mine. I put it back on top, and the screw is about 2 1/2 turns off the nut.

Backing the PMS out, may fix what ails you, but I would double check the main, and step to the 172.5 at least. The 167.5, is lean for the bigger 1700's, IMHO.
 
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#850124
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Re:coughing just off idle 3 Years, 1 Month ago  
at 2-1/2 turns the bike burns your eyes at idle and the pipes are black (to rich). I got to the tune I have trying to clean up the pipes. I tried the 35 pilot and the PMS was about 4-1/2 turns out before it idled best so Shane at SS told me to put the 37.5 in and he said it would probably run about 1 turn out at my elevation. Shane also told me to put in the 67.5 main, and the bike seemed a lot better than with the 72.5 I have tried.
 
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#850134
Curt (Moderator)
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Re:coughing just off idle 3 Years, 1 Month ago  
You've got something else going on because the advice you just got is good. If you get tired of beating your head against the wall make a trip over here to see me and we will work on it.
 
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#850135
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Re:coughing just off idle 3 Years, 1 Month ago  
Rocketman wrote:
at 2-1/2 turns the bike burns your eyes at idle and the pipes are black (to rich). I got to the tune I have trying to clean up the pipes. I tried the 35 pilot and the PMS was about 4-1/2 turns out before it idled best so Shane at SS told me to put the 37.5 in and he said it would probably run about 1 turn out at my elevation. Shane also told me to put in the 67.5 main, and the bike seemed a lot better than with the 72.5 I have tried.

Did you check the float level??? If it is to high it will give all the indications you have mentioned. The 172.5 is the correct main jet. I also don't know why Shane told you anything about at your altitude. If you are running the OEM carb it is a CV carb and altitude does not come into play at all. If you have a HSR 42 flatslide carb it would make a difference. What do you have??? OEM or HSR?? Big difference and we would need to know to give the proper jetting info.
 
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#850136
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Re:coughing just off idle 3 Years, 1 Month ago  
Do you keep dropping the 100 part of the 167.5, on purpose, or is it really a 67.5?

These bikes will always run rich at idle. That's why the AIS works there. It helps burn the unburned fuel. If the AIS is gone, then there is nothing burning the unburned fuel exiting the cylinders at idle.

The inside of the exhaust will never not be black. If you are getting a fluffy carbon buildup in the ends, then it may be to rich. If it is just enough to coat the ridges of your finger tips, your good. It will probably lighten on a road trip, but get dark again when you ride around town.
 
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#850138
Rocketman (User)
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Re:coughing just off idle 3 Years, 1 Month ago  
Let me try the combination y'all suggest and check the float level again, and if I can't get it to work I may contact you and make the ride out sometime. Thank you Curt.
 
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#850140
Rocketman (User)
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Re:coughing just off idle 3 Years, 1 Month ago  
okay Sorry it is 67.5, and I didn't realize that about the idle let rethink this and make the changes y'all suggest and see what I wind up with I really appreciate the help guys.
 
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