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Eastbound and Down
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Discussion Starter #1
I'm in the process of going through the steps of adjusting my S&S carb per their instructions on my 1988 softail springer. It says to adjust Idle Speed Adjusting Screw until the rpm range is between 950 to 1050 rpms. My problem is that my bike does not have a tach. Can anyone give some insight as to what 950-1050 sounds like.
 

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Retired citizen
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22,068 Posts
Just get the engine down to a slow idle with the butterfly idle screw then adjust the idle jet screw in and out until you get the fastest rpm. The idle mixture will be set, then adjust the butterfly idle screw to get it close to about 950 rpm. Crack the throttle a few times and if the engines revs without bogging or spitting you're done.
 

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Retired citizen
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Also 950 to 1050 rpm sounds like just above potato, potato, potato !
 

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Eastbound and Down
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Discussion Starter #4
Just get the engine down to a slow idle with the butterfly idle screw then adjust the idle jet screw in and out until you get the fastest rpm.
Based on what S&S calls them is the butterfly idle screw the idle speed screw and the idle jet screw the idle mixture screw?
 

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Retired citizen
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Right. The idle screw is on the left side of the carb by the throttle cable, the idle jet is on top of the carb. The right side screw is for adjusting the accelerator pump.
 

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Eastbound and Down
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94 Posts
Discussion Starter #6
On my way to the garage right now. Thanks for the help.
 

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Eastbound and Down
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Discussion Starter #7
Also 950 to 1050 rpm sounds like just above potato, potato, potato !
Schmidty, I posted a video to youtube. I thought it may help with finding the 950-1050 rpm range If you could have a listen and let me know if i'm there or need to increase/decrease..


 

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I think that sounds about like 1072 RPM. :D


Is that after a ride when the motor is nice and hot?
 

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Eastbound and Down
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Discussion Starter #9
Is that after a ride when the motor is nice and hot?
Couldn't get it out for a ride because of a little one at home. All I could do was let it run for about 5 minutes. After making adjustments I went up and down the street a couple times. It sounded the same after the ride too.

In all seriousness though you think rpm's are okay?
 

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Sounds like it might be a little bit too high.

It might be slightly higher than that when it is fully warmed up...

You'll just have to try it and see.
 

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Eastbound and Down
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Discussion Starter #11
Sounds like it might be a little bit too high.

It might be slightly higher than that when it is fully warmed up...

You'll just have to try it and see.
I'll play with it some more a little later when I can get out for a ride and go from there. Thanks for the feedback.
 

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Eastbound and Down
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Discussion Starter #13
It might be slightly higher than that when it is fully warmed up.
You were spot on. Just came back from a ride and it was definitely running higher. Slowed it down a bit. My only concern is I went too low. Have a listen.

 

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Yep, I'd put it half way between the setting previously and where it is now.


Sounds great where it is now, but it is not turning the oil pump fast enough to get the oil pressure where it needs to be.
 

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Eastbound and Down
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Discussion Starter #17
go to their web site & download the tuneing instructions.its got pictures which i can't copy & paste
Yeah, I started there, but my problem was that I don't have a tachometer on this bike and was having a hard time finding the 950-1050 rpm range.
 

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Eastbound and Down
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Discussion Starter #19
Yep, I'd put it half way between the setting previously and where it is now.


Sounds great where it is now, but it is not turning the oil pump fast enough to get the oil pressure where it needs to be.
Ahh...that explains it. I only turned it about 1/8 to 1/4 of a turn and I think it's where it needs to be. Fun carb to play with, but it sure is touchy.
 

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Eastbound and Down
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Discussion Starter #20
Here's the final result. The bike didn't want to stay running at the lower setting after sitting for a bit. I think this should do it.

 
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