Quick questions about idle and such
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6th Gear
Joined: Oct 2011
Posts: 10
Likes: 0
From: Chicago Suburbs
Quick questions about idle and such
Alright its a 1975 FXE, and i have some questions.
Ok, first off, is it normal at all for the idle to jump up a couple hundred rpms after a few minutes of riding when the bike gets nice and warm?
Secondly, when i roll the throttle too quickly, the bike dies out. Mind you, this bike has a S&S Super B carb with the accelerator pump conversion on it. Do you guys think thats why it does that, or maybe the jets just need a good cleaning?
Sorry if these are dumb questions, but everything i know about shovels comes from my dad and he for sure has his own "home mechanic" opinions on things. So i just wanted to get some advice from you dudes. Thanks!
Ok, first off, is it normal at all for the idle to jump up a couple hundred rpms after a few minutes of riding when the bike gets nice and warm?
Secondly, when i roll the throttle too quickly, the bike dies out. Mind you, this bike has a S&S Super B carb with the accelerator pump conversion on it. Do you guys think thats why it does that, or maybe the jets just need a good cleaning?
Sorry if these are dumb questions, but everything i know about shovels comes from my dad and he for sure has his own "home mechanic" opinions on things. So i just wanted to get some advice from you dudes. Thanks!
No, it's not normal. You have to ask yourself a question.....When is the throttle gonna stick open, more than a couple hundred rpm? That is a sick feeling. Been there, Done that.
When the motor is cold, loosen the throttle cable screw at the throttle shaft, and make sure the butterfly closes. before you tighten the screw down, start the bike and make sure it is at idle, 900 to 1000 rpm. At this point, I like a tad bit of slack in the cable, but tighten the cable screw. Start it up, ride it around and see if the idle changes. If it does, see if the accelarator pump is keeping it from returning properly. Check the throttle shaft to see if it is binding.
Check to see if your idle jet is adjusted properly.
I'm sure there are others that will chime in on this.
Start simple and move to difficult.
There are no dumb questions when it comes to safety!
When the motor is cold, loosen the throttle cable screw at the throttle shaft, and make sure the butterfly closes. before you tighten the screw down, start the bike and make sure it is at idle, 900 to 1000 rpm. At this point, I like a tad bit of slack in the cable, but tighten the cable screw. Start it up, ride it around and see if the idle changes. If it does, see if the accelarator pump is keeping it from returning properly. Check the throttle shaft to see if it is binding.
Check to see if your idle jet is adjusted properly.
I'm sure there are others that will chime in on this.
Start simple and move to difficult.
There are no dumb questions when it comes to safety!
Last edited by AlCherry; Jun 3, 2012 at 05:30 PM.
Thread Starter
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6th Gear
Joined: Oct 2011
Posts: 10
Likes: 0
From: Chicago Suburbs
Alright, I checked all of that stuff out last night, and it all seems to be functioning properly. The butterfly is opening and closing just the way its supposed to, and the accelerator pump isn't getting caught up on anything, but the idle is still super high after a little bit of riding.
Club Member
Joined: Mar 2009
Posts: 66,122
Likes: 51,433
From: Niles Canyon Ca.
The old S&S B's had a issue with the throttle shafts wearing out and sucking air , would make the bike act like what you describe . I ran that same setup for years , wore out several bodies . Second issue would be replace the accel pump assembly those pump bowl kits used the same one as the old butterfly keihin carbs and the leather does get hard or worn and doesn't do it anymore and those haven't been popular in 20 plus years so it's got time on it .
Warm the bike up and at an idle take a can of brake clean and just short fast bursts shoot the intake clamps one at a time and then each side of the carb around the throttle shaft . She drops off you found your leak .
This doesn't do it what jets you running ? Some of them like the .033 for the intermediate ( long one ) and 70 -72 on the main depending on you elevation , over 5000 ft drop it to .031 & 68 .
Proper setting should 1-1/2 out from seated and +or - 1/4 turn when warm , run it a little on the fat side and see what happens .
Warm the bike up and at an idle take a can of brake clean and just short fast bursts shoot the intake clamps one at a time and then each side of the carb around the throttle shaft . She drops off you found your leak .
This doesn't do it what jets you running ? Some of them like the .033 for the intermediate ( long one ) and 70 -72 on the main depending on you elevation , over 5000 ft drop it to .031 & 68 .
Proper setting should 1-1/2 out from seated and +or - 1/4 turn when warm , run it a little on the fat side and see what happens .
Road Master
Joined: Apr 2012
Posts: 979
Likes: 38
From: new orleans,la
74" main jet sea level 68 --high alt.. 66 --- 80" sea level 70 high alt 68 99% of the time the 295 intermediate jet.. also check the accelerator pump if it has a flat spot it might be squirting to late.. i have a 80" open pipes,leinweber L3S i run a 70 main and a .295 had to adjust the accel pump to squirt sooner. im at sea level ... i also run a set of 2001 honda prelude finisher cones on the end of my drag pipes -- they have a reduced hole in the cone and a chamber that gives me back my low end with out robbing me of top end.. found those by pure accident total amazement they work so well..
Club Member
Joined: Mar 2009
Posts: 66,122
Likes: 51,433
From: Niles Canyon Ca.
Only time I've got a .295 jet to run in the S&S is the later E shorty carbs every B model it's been too lean . I have to wonder if the B's are touchy about the amount of water in the air with humidity , out here at sea level ours is low well under 40% and every B I've set up wants .031 minimum .
Road Master
Joined: Apr 2012
Posts: 979
Likes: 38
From: new orleans,la
if your gonna run a carb its best to have a selection of both jets-- what works for you might not work for the next guy-- i have 64 through 80 mains and every size idle tube.. also if the guy with the 75 fxe has mufflers as you know it will affect what jets-- by the look of his whale bike hes probably got mufflers --- if i were him i would get a 68,70 main and .295 through .33 idle in the morning when i fire up the bike i have to turn the A/F screw out a 1/2 turn -- when its warm i can turn it back in... an L3S doesnt idle like a normal harley anyways.. maybe my honda cones cause some restriction and thats why the .295 works-- i just love the power off the line with open drags and i dont have to revvvvv the engine way up just slight revvvs and nail it.. with belt drive--- 22 tranny and 47 rear it takes off like a bat out of he11.. i also use that DaVinci booster kit on the discharge tube..
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Club Member
Joined: Mar 2009
Posts: 66,122
Likes: 51,433
From: Niles Canyon Ca.
I've the big shop S&S jet kit , over a 100 assorted in the thing been running the B's over 30 years got a box full of them still .
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