Last fall I didn't put Sta-Bil in the tank of my wife's 2005 1200 Cutsom sportster. Got it out of storage this spring and it took quite a bit to get it started but eventually it did run. It didn't get ridden for a while after that and first time she took it out it spit and sputtered horribly at low idle, dying often. I changed plugs, which were dry black and sooty, new ones went in along with a fresh tank of fuel and we tried again. Same results within 15 minutes and that includes warm up time and "riding" time. Bought new jets (same sizes as what is already in bike). Original Idle jet was at least halfway plugged, cleaned carburetor and air cleaner and reassemble with new parts. New plugs and fired it up. Idled perfectly off and on. Took it for a drive and back to same results within blocks.

Only other thing that has been changed since it was put away last winter was that I swapped out the grips for a different style. I marked the adjusters by the grip and reset the cables to that after putting the new grip on. since the new and old grips were the same diameter I assume that should have gotten me damn close to start. and shouldn't be causing this problem.

Any ideas what to try next? Only thing I can think of is to try to lean out the carb with the mixture screw in the bottom but don't really want to mess with that bcuz if I am wrong I will only make it worse. Plus, I haven't changed it yet so it should still be right, shouldn't it?

 

Going back to the mark is not going to work if you rerouted the cables at all. To adjust both cables (assuming you have two) You should tighten the grip mounts,
then, if there is play in either cable, take up the slack until the throttle opens and closes all the way with no play in the throttle, then back off a hair so they are not binding.
If they are both tight, back off a little at a time until you feel play in the throttle, take up the slack, then back off the afore mentioned "hair".
Assure that the throttle at the carb is free to fully rotate to idle position.

 

Cables were only unhooked at the grip, never rerouted from where they were but I am going to readjust them just to be sure. I found a great video on youtube that shows what you are explaining very clearly. Thanks

 

May have nothing to do with the carb...

could be the crank position sensor.

Common problem on the early rubbermounts, including my '05 when it had 20k miles on it.

 

My guess is it has nothing to do with the grips or cabling. The bike was running fine when you stored it and you already know it had contamination from storage so I would focus on that aspect. Once contaminated they can be a pita to completely clean without total disassembly. First thing I would check for is any air leaks, I isually do this with a propane torch (not lit of course!!!!). If it stops stumbling (or runs different at all) when the propane is near it you have a vac leak near that spot (I would focus on the manifold where the carb attaches to the motor, I usually put a little grease on either when I reassemble to make a good seal). A fairly common problem if you disassembled it to install the new jets. If that checks out I would pull the carb again and give it another cleaning/soaking. I find my air compressor works well with the rubber tipped gun attachment for this. Blow out all of the passageways soak, repeat, etc. A good idea to wear glasses when blowing out the orifices and looking at the carb, just trust me on that one. It sounds a lot like a fuel delivery problem.

Hopefully the guy who was asking about carb vs. EFI reads this thread. Forgetting the stabil, especially for the riders in colder climates where they switch the gas blends usually causes a problem for the carbed bikes.

 

Buy a can of Seafoam and run through your fuel system. I'd take out the fuel petcock assembly and clean the screen, could be a bunch of gooey junk clogging up the whole system. Really no need for new jets, sounds like a typical issue of long term storage without fuel stabilizer, very common.


John

 

This....and replace the fuel line from tank to carb. {I've had a few of them 'breakdown',and repeated screw up the carb with tiny black chunks.

 

If the new plugs were black and sooty within 15 minutes, the bike has to be running PIG rich. This is the opposite of what occurs if a jet is clogged which results in a lean condition.

The only way to effectively clean a carb is to disassemble it and give it a good soak in cleaner, followed by blowing out all the passages with compressed air. If it hasn't been done already, an 05 carb is probably ready for a complete rebuild anyway.

Another possibility for an extremely rich condition, is a bad fuel petcock diaphragm. If the old diaphragm has gone bad, it can allow fuel to be sucked through the petcock vacuum hose. This can usually be checked by looking into the vacuum hose for traces of fuel, after the bike has been run for a bit.

 

i agree with the above posters, first ensure the carb is getting a steady supply of fuel by checking the petcock, its a vaccum petcock right? After that go through the card with compressed air and carb cleaner, check the float too. Maybe check for intake manifold leaks too.

if all that checks out then i would look at ignition, i have a good crank sensor ill sell ya cheap if you get to that point, email me if ya need it awoz87@gmail.com

 

As with woz's comment above, make sure that your vacuum line to your petcock valve is in good shape. If it is cracked it won't let the petcock valve open up fully and allow the correct amount of flow to the carb.