2000 FLSTC Idle Issue
2000 FLSTC Idle Issue
Hey everyone,
I've got a 2000 FLSTC with an idle issue that I'm having trouble figuring out. Initially the bike was having issues running in general, it wouldn't stay on without the throttle and even when it was on it ran like garbage. I replaced the CV carb with a new one, cleaned out the jets from the old carb (Because the jets that came with the new one were too small), reinstalled everything and now the bike will run and idle (For the most part) but only with the choke on..As soon as I push the choke in the tinniest bit the bike will immediately shut off and won't turn back on again until the choke is pulled back out even when warm. Also if I let the bike sit and idle for a few with the choke on it starts to bog down a bit and needs a blip of the throttle to keep on. When I twist the throttle the bike will happily rev to the moon and doesn't break up or sound choppy in the slightest.
As for mods I believe this bike has a Screamin' Eagle intake and a set of Vance & Hines long shots though I'm not 100% sure on the intake as this bike was inherited, not purchased but I did find the original intake stuffed away so I know whatever's currently on there isn't the oem one.
Any ideas would be much appreciated, Please bear with me if this is a simple fix, I'm used to working on cars not motorcycles
I've got a 2000 FLSTC with an idle issue that I'm having trouble figuring out. Initially the bike was having issues running in general, it wouldn't stay on without the throttle and even when it was on it ran like garbage. I replaced the CV carb with a new one, cleaned out the jets from the old carb (Because the jets that came with the new one were too small), reinstalled everything and now the bike will run and idle (For the most part) but only with the choke on..As soon as I push the choke in the tinniest bit the bike will immediately shut off and won't turn back on again until the choke is pulled back out even when warm. Also if I let the bike sit and idle for a few with the choke on it starts to bog down a bit and needs a blip of the throttle to keep on. When I twist the throttle the bike will happily rev to the moon and doesn't break up or sound choppy in the slightest.
As for mods I believe this bike has a Screamin' Eagle intake and a set of Vance & Hines long shots though I'm not 100% sure on the intake as this bike was inherited, not purchased but I did find the original intake stuffed away so I know whatever's currently on there isn't the oem one.
Any ideas would be much appreciated, Please bear with me if this is a simple fix, I'm used to working on cars not motorcycles
Cruiser
Joined: Apr 2009
Posts: 178
Likes: 11
From: Billings, MT
id say your "cleaned out" jets are not clean at all. especially the idle jet. buy some new replacements in the right size, and i bet your troubles all go away. ive tried the cleaning them out route, even the drilling them out route, and none were completely successful. in fact, id buy an extra set of jets one size up, so you can fine tune a bit once you get it to idle.
id say your "cleaned out" jets are not clean at all. especially the idle jet. buy some new replacements in the right size, and i bet your troubles all go away. ive tried the cleaning them out route, even the drilling them out route, and none were completely successful. in fact, id buy an extra set of jets one size up, so you can fine tune a bit once you get it to idle.
Nope, haven't touched anything besides the carb itself. As far as I can tell the tank and petcock are original. No rust or corrosion anywhere on the bike including inside the tank, fortunately it's been stored indoors it's entire life.
Seasoned HDF Member
Joined: Sep 2008
Posts: 14,159
Likes: 11,249
From: San Diego, CA
A new vacuum hose to carb, and/or new diaphragm would be a cheap, easy fix if it's your problem. Maybe due as a preventative maintenance item on a bike that old....
Many, myself included, just cap the carb vacuum port, and use an aftermarket (Pingle) petcock in place of OEM..... no more vacuum back up, I just remember to turn off the petcock, like in my old shovel head days...
PS- if you have access to an ultrasonic cleaner, they work wonders on gummed up carbs and jets... I disassembled a CV40 carb, put the parts in a friend's ultrasonic cleaner for a couple cycles. The parts came out looking like new...
Last edited by hattitude; Mar 18, 2020 at 10:11 AM.
The vacuum petcocks require the petcock be open AND a vacuum diaphragm be actuated by vacuum from a running engine to open. It's a failsafe (nanny device) for those who forget to turn off the petcock. The diaphragm and/or the rubber hose between the petcock to carb (for vacuum) can deteriorate with age. It can cause the symptoms you describe..
A new vacuum hose to carb, and/or new diaphragm would be a cheap, easy fix if it's your problem. Maybe due as a preventative maintenance item on a bike that old....
Many, myself included, just cap the carb vacuum port, and use an aftermarket (Pingle) petcock in place of OEM..... no more vacuum back up, I just remember to turn off the petcock, like in my old shovel head days...
PS- if you have access to an ultrasonic cleaner, they work wonders on gummed up carbs and jets... I disassembled a CV40 carb, put the parts in a friend's ultrasonic cleaner for a couple cycles. The parts came out looking like new...
A new vacuum hose to carb, and/or new diaphragm would be a cheap, easy fix if it's your problem. Maybe due as a preventative maintenance item on a bike that old....
Many, myself included, just cap the carb vacuum port, and use an aftermarket (Pingle) petcock in place of OEM..... no more vacuum back up, I just remember to turn off the petcock, like in my old shovel head days...
PS- if you have access to an ultrasonic cleaner, they work wonders on gummed up carbs and jets... I disassembled a CV40 carb, put the parts in a friend's ultrasonic cleaner for a couple cycles. The parts came out looking like new...
Do you know what I might be able to look for on the bike that could identify what type of petcock it has (vacuum or Pingle as you said)?
Seasoned HDF Member
Joined: Sep 2008
Posts: 14,159
Likes: 11,249
From: San Diego, CA
That might very well be the culprit. The old carb had what looked like a vacuum hose on it that I couldn’t find the connection for on the bike. The carb on there now has a vacuum port on the bottom that I blocked off and now just has 1 hose running to it (the main fuel line)
Do you know what I might be able to look for on the bike that could identify what type of petcock it has (vacuum or Pingle as you said)?
Do you know what I might be able to look for on the bike that could identify what type of petcock it has (vacuum or Pingle as you said)?
You may not have vacuum petcock if it's vacuum line is missing and the bike still runs at all.... If you have a non-vacuum petcock, and with your symptoms, I'd suspect the jets/carb are dirty, carb adjustment, and/or a vacuum leak at the carb intake manifold seals... Those carb manifold vacuum seals can be a bear to seal, especially if they are old/brittle... A leaking intake manifold will cause your symptoms because the bike will be running lean. It will need the choke to idle, and will be very lean at higher RPM... it will usually cause popping during deceleration ....
In any case, to identify the vacuum petcock, I have attached a few pics...
1) is the parts diagram of the petcock (#27), it's vacuum line (#18) and you can see where the vacuum line attaches to the back (inboard/engine side) of the petcock.
2) is the part number break down and discounted price of a new HD part in the far right column.
3) a pic of a new vacuum petcock
Good luck with your diagnosis/repair....
Last edited by hattitude; Mar 18, 2020 at 11:28 AM.
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Hmmm... If the petcock has NO Vacuum line to it, and it's working, no fuel will get through and the bike won't run... If the vacuum line is leaking slightly, at idle, the fuel delivery will be erratic, but once RPMs increase, and vacuum increases, the petcock will open. If you have the vacuum line disconnected, the petcock shouldn't open... If the vacuum petcock has NO vacuum line attached AND the diaphragm is leaking... I'm not sure what to expect from fuel flow..???
You may not have vacuum petcock if it's vacuum line is missing and the bike still runs at all.... If you have a non-vacuum petcock, and with your symptoms, I'd suspect the jets/carb are dirty, carb adjustment, and/or a vacuum leak at the carb intake manifold seals... Those carb manifold vacuum seals can be a bear to seal, especially if they are old/brittle... A leaking intake manifold will cause your symptoms because the bike will be running lean. It will need the choke to idle, and will be very lean at higher RPM... it will usually cause popping during deceleration ....
In any case, to identify the vacuum petcock, I have attached a few pics...
1) is the parts diagram of the petcock (#27), it's vacuum line (#18) and you can see where the vacuum line attaches to the back (inboard/engine side) of the petcock.
2) is the part number break down and discounted price of a new HD part in the far right column.
3) a pic of a new vacuum petcock
Good luck with your diagnosis/repair....
You may not have vacuum petcock if it's vacuum line is missing and the bike still runs at all.... If you have a non-vacuum petcock, and with your symptoms, I'd suspect the jets/carb are dirty, carb adjustment, and/or a vacuum leak at the carb intake manifold seals... Those carb manifold vacuum seals can be a bear to seal, especially if they are old/brittle... A leaking intake manifold will cause your symptoms because the bike will be running lean. It will need the choke to idle, and will be very lean at higher RPM... it will usually cause popping during deceleration ....
In any case, to identify the vacuum petcock, I have attached a few pics...
1) is the parts diagram of the petcock (#27), it's vacuum line (#18) and you can see where the vacuum line attaches to the back (inboard/engine side) of the petcock.
2) is the part number break down and discounted price of a new HD part in the far right column.
3) a pic of a new vacuum petcock
Good luck with your diagnosis/repair....
I messed with the enrichment screw on the carb as well and I believe it's about half a turn out (I tried putting it in all the way but then the bike wouldn't start) but still won't idle so I'm really confused as to what the problem is since the carb is brand new, the idle jet is new, and I replaced it with the same sized jet that came out of it which I know is the right size because it's what the bike had the last time it was ridden (And before it got parked it ran great) and since the carb is new I would imagine I wouldn't need a larger idle jet to compensate for the aging carb.
According to a quick google search most people recommend about 30-45 seconds for the choke to be in before the bike is warmed up and then it can be released. I let this bike idle for several minutes and even then it still stalls
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Cruiser
Joined: Apr 2009
Posts: 178
Likes: 11
From: Billings, MT
i would still try one or two sizes up on the idle jet. it may be the same size that came out of the old carb when it was running before, but every carb is gonna have some small differences in the way they run, even on the same motor. jets are cheap, and easy to replace. i wouldnt overthink the "why", i would make it run right from here on out.
i went thru this with my wifes 04 heritage that sat for a year or more from the previous owner.
i went thru this with my wifes 04 heritage that sat for a year or more from the previous owner.
Seasoned HDF Member
Joined: Sep 2008
Posts: 14,159
Likes: 11,249
From: San Diego, CA
Thank you for all the info! I checked the petcock today and it turns out I don't have a vacuum one, it only has a single port coming off it and it goes right to the carb. I replaced the pilot jet with a brand new one and adjusted the idle on the bike and now it idles without bogging like it's going to die, but will still die if I push in the choke. However I was able to push it in a little further today than yesterday before it died but not by much. Probably not even 1/4 of the way in. I didn't replace the main jet (The larger one) nor the emulsion tube because the new jets were too small for the emulsion tube but they're both definitely clear of obstructions as I can see clearly through all the holes when it's dry. As for the carb to intake gasket I'm not sure how old it is, but it's still very malleable and not stretched/warped nor dry or cracking.
I messed with the enrichment screw on the carb as well and I believe it's about half a turn out (I tried putting it in all the way but then the bike wouldn't start) but still won't idle so I'm really confused as to what the problem is since the carb is brand new, the idle jet is new, and I replaced it with the same sized jet that came out of it which I know is the right size because it's what the bike had the last time it was ridden (And before it got parked it ran great) and since the carb is new I would imagine I wouldn't need a larger idle jet to compensate for the aging carb.
According to a quick google search most people recommend about 30-45 seconds for the choke to be in before the bike is warmed up and then it can be released. I let this bike idle for several minutes and even then it still stalls
I messed with the enrichment screw on the carb as well and I believe it's about half a turn out (I tried putting it in all the way but then the bike wouldn't start) but still won't idle so I'm really confused as to what the problem is since the carb is brand new, the idle jet is new, and I replaced it with the same sized jet that came out of it which I know is the right size because it's what the bike had the last time it was ridden (And before it got parked it ran great) and since the carb is new I would imagine I wouldn't need a larger idle jet to compensate for the aging carb.
According to a quick google search most people recommend about 30-45 seconds for the choke to be in before the bike is warmed up and then it can be released. I let this bike idle for several minutes and even then it still stalls
My 2001 FXST has a CV40 Carb with 45/190 jets. I also added a different needle... mine has a stage1...
I followed the tuning techniques & other advice from the CV Performance web site after I took it apart and rebuilt it (I bought it used)..
That bike starts right up at full choke.... after about a minute it runs well about 1/3 choke... when it's fully warm, which can take a few miles, I turn off the choke and it idles/runs really well... On hot starts, it seems to fire up with the first rotation from the starter. If this had a kick starter, it would be a one kick bike.... Once you get that carb dialed in... the bike will run well, and strong...
Check out the CV Performance web site for some guides and tuning info... I don't agree with all their suggestions, but they put out some pretty good info..
https://cv-performance.com/harley-cv...-tuning-issues
https://cv-performance.com/harley_mixture_screw_tuning
https://cv-performance.com/instructions-guides
Last edited by hattitude; Mar 18, 2020 at 09:33 PM.