help with S&S super breaking up over 65MPH
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Road Master
Joined: Jun 2006
Posts: 905
Likes: 207
From: Minneapolis
help with S&S super breaking up over 65MPH
I own an 88 Evo S&S Superstock bottom end, HD jugs and heads. The motor was just built and has a Carls Cam but nothing that special. I've worked the Super E carb over with various jets and accel pump adjustments and even added torque cones but I can not get the bike to accelerate through 65 MPH and on...it just breaks up and goes dead then comes back to life as I close the throttle....if I twist the throttlwe sharply I can sometimes get the motor to "grab" and go at 60 to 65. It seems to be starved for gas. I have verified the tank flows fuel. Carb is new as well.
Any help would be great as I'm ready to give up.
Any help would be great as I'm ready to give up.
Elite HDF Member
Joined: Sep 2007
Posts: 4,468
Likes: 12
From: Bluffton, South Carolina
Does the engine rev up ok in the other gears? When it "breaks up" does it pop through the carb or backfire through the pipes? What are you running for jets? Have you checked the float level and what petcock are you running, as it could be a fuel supply (petcock, float level, cloggged fuel line/filter, or tank vent) problem if the electrics are OK. This should get you started, hope this helps.
Advanced
Joined: Aug 2008
Posts: 89
Likes: 0
From: kentucky
i had the same prob when i put my super e on. what you need to do is re adjust the carb. im using the jet that came in the card so im not sure what size i never payed any mind to it start the bike ride it down the road just enough to warm it up so it will idel right befor you do it . i adjusted mine so when warm it will idel about 800 rpm then when seting it drops down to 5 or 600. also i put screaming eagle plugs and wires on mine and it helped it greatly
Road Warrior
Joined: May 2009
Posts: 1,945
Likes: 4
From: Victoria, Australia
ferger, re-read what John T says and let us know the jet sizes and answers to his queries.
Having run a Super E for a number of years (and having tuned it to death more times than I want to say!) it sounds to me like you are running a little small on the high speed jet but I take your comment onboard that you have tried different jets, checked fuel flow etc. and it still stumbles.
"It seems to be starved for gas." Could be low fuel level in the bowl which is easy to check and correct--adjustment procedure is in the manual.
Please tell us the cam specs and any other parts/work on your motor.
What ignition are you running? This is kinda stretching a bit but it could be an ignition problem that appears at that speed range.
One more--a new carb can have a bit of junk in the orifices so clean them out in accordance with the pix in the manual. Could also just be bad luck to have a faulty carb--it does happen....
More info would be a help in the diagnosis...
Regards,
V2Evo96
Having run a Super E for a number of years (and having tuned it to death more times than I want to say!) it sounds to me like you are running a little small on the high speed jet but I take your comment onboard that you have tried different jets, checked fuel flow etc. and it still stumbles.
"It seems to be starved for gas." Could be low fuel level in the bowl which is easy to check and correct--adjustment procedure is in the manual.
Please tell us the cam specs and any other parts/work on your motor.
What ignition are you running? This is kinda stretching a bit but it could be an ignition problem that appears at that speed range.
One more--a new carb can have a bit of junk in the orifices so clean them out in accordance with the pix in the manual. Could also just be bad luck to have a faulty carb--it does happen....
More info would be a help in the diagnosis...
Regards,
V2Evo96
Extreme HDF Member
Joined: Nov 2006
Posts: 13,389
Likes: 26
From: Windham,Maine
Also an S&S guru,and as you have read it has to be carb jetting.Have you looked at your plugs to get an idea where your at.Most of your riding is done on the intermediate jet,when the main jet starts to flow,if it is to fat it will bother the same as when it is too lean.
Road Warrior
Joined: May 2009
Posts: 1,945
Likes: 4
From: Victoria, Australia
fergerburger, have you had a chance to investigate your issue as yet?
We would like to hear how your going when you get a chance to post...
Regards,
V2
We would like to hear how your going when you get a chance to post...
Regards,
V2
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Elite HDF Member
Joined: Sep 2007
Posts: 4,468
Likes: 12
From: Bluffton, South Carolina
If it gains power when you let off, then you are too lean, if it gets worse then you are too rich. Don't forget to check the tank vents.Hope this helps.
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3rd Gear
Joined: Jul 2007
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From:
"I own an 88 Evo S&S Superstock bottom end, HD jugs and heads."
Keep in mind that S&S uses different timing marks than Harley. Alot of aftermarket ignitions are static timed off the advance mark on the flywheels, not TDC.
Could be timing, not carb issues?
What do the plugs look like???
Keep in mind that S&S uses different timing marks than Harley. Alot of aftermarket ignitions are static timed off the advance mark on the flywheels, not TDC.
Could be timing, not carb issues?
What do the plugs look like???
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