hey yall

bit of a long post, but im just bein detailed-

ive done my fair share of research throughout the forum and i have found several posts very useful, and will soon employ their suggestions, but as i do, and while ive got the day off, i thought id post about my issue.

quick history-i bought this bike (2001 Sportster 1200S) about one month ago from a dude who has had it garaged for about a year. He bought it off a friend and pretty much didnt touch it. he told me that he had it serviced. im not inclined to believe him because over the month i have found a handful of small issues that probably would have been addressed.

the bike starts up great, i give it a little choke and its warm pretty fast.

problem:
i have found that ill be stopped (red light, stop sign, what have you) and when i take off i have to slowly (too slowly) let out the clutch and nearly pin the throttle in order to keep the bike from dying. the acceleration is pretty poor at this point. it actually sounds like there is a half second of stalling or bottoming out before it picks back up. usually ill be going through the intersection talking to the bike, "dont ****in die, dont do it." it has not died while on the road, but i bet if i backed off the throttle while going through the light that it would.

i went to change the grips out and noticed that the idle cable was pretty shredded, so i picked up a new one and installed it yesterday. throttle cable looks a-ok and the idle cable properly returns the throttle grip to the proper position, ie the mechanics seem fine here. the first point in the service manual (page 4-3) for poor acceleration is "throttle cables misaligned-adjust throttle cables." I feel that this may have improved the situation slightly, but not much.

the bike came with two sets of pipes, the stock and the loud pipes. they are both HD, but i dont know what type they are, all i know is that the loud pipes are baffleless. i had been riding the bike with those, so i thought, "maybe the engine needs the back pressure of the stock pipes." swapped to those, no improvement.

the idle rpm sounds like it is in a good place, and from the outside the carb looks good, though i think ill be taking it off and cleaning today since it sat for so long without use.

i took the air cleaner off, turned the bike on and watched the carb work. fuel seems to spit well, the only thing i notice is that it seems like perhaps the butterfly valve doesnt quite open quickly enough. i know it is connected to the throttle, but when it swings open, i can see fuel bounce right off of it back into where the air filter would be. the throttle cable is tight enough (there is no "empty zone" of pull on the grip).

i can actually kill the engine if i get the throttle timing right. watch the videos ive posted here, they pretty much illustrate my issue. sorry for gnarly quality-using a blackberry and it wouldnt stop recording when i hit the button. c'est la vie.

in this video (air cleaner off) (https://vimeo.com/46781576) you can hear at 0:28-29 that the engine pretty much dies and picks up. giving it baby pulls on the throttle results in this. its in the first quarter of the throttle pull that it nearly dies. this happens several times and you can tell again around :54-56. then it dies at 1:22

this is the other video (air cleaner on) (https://vimeo.com/46781575) and it dies quicker.

My hunch at this point is that its an air intake issue. i have no idea where to start with that. i have a screamin eagle stage 1 air kit (as is stock with the 1200S).

if youve made it this far in the post-thanks for reading! i know i probably overwrote, but i figure the more details the better. also-im in the los angeles area so if anyone is in the area too and wants to tinker, lemme know, ill be there, or you can come here. backyard, garage, and beers...

have a rad one yall!

brett.

 

I had a old suzuki that sounded like that does. Had the carb jetted for my intake and exhaust, a valve job, and then the carb tuned and it cleared it right up...........other guys know alot more than me and i have no idea what the actual problem would be but it worked for me.

 

i think the carb is a potential source of the issue. i rejetted my suzuki SV after changing to a baffleless exhaust and i immediately noticed the difference in its idle. i had to fiddle with the air/fuel screw too. my issue is im not set on either of these sets of pipes being the pipes i keep, so maybe i just get a set i like and rejet the carb from there...

 

If the bike sat for a year without any stabilizer in the gas, your carb is likely gummed up with varnish. I'd disassemble the carb and give it a good cleaning before messing with anything else.

 

so i have taken the carb off, gave it a thorough check and cleaning, and decided to replace both diaphragms, the float bowl o-ring, the accelerator pump o-ring, pretty much every screw...and i think thats it.

check out this melted diaphragm i found inside!!



now the bike turns over but the engine wont start...really bummed out.

my current carb settings are 45 (slow) / 195 (main) , 1 shim on the needle, screw is 2.5 turns out. this is how i received the bike. i have learned that the stock jetting is 42/195 for the 49 state, 1200S, but is it California's setting? Also, feeling like this is a big too much fuel...should i go to 175 mains, remove the shim, go to 2 turns?

i also noticed that my bike is missing the fuel tank-to-vapor valve hose...could this really be a problem? im not sure that it was there earlier, when the bike was starting, and with all the old carb stuff.

 

alright, well i know its not a vapor hose problem. enough people on here said theyve been riding without it for some time. im just really stumped as to why, after cleaning and replacing parts in the carb, the bike wont start. everything is installed.
i took out the two left spark plugs. the rear cylinder plug was pretty saturated, but essentially the plug was clean and looked good. the forward cylinder plug was caked with black dust, but not wet at all.

 

ive rebuilt the carb, installed 4 new spark plugs, removed the shim from the needle, and turned the mixture screw to 2 turns out, and adjusted the idle. i am running 45/195 on the jets.
i have noticed almost 50% improvement in the acceleration, but the engine still wants to die when i start moving from a stopped position. in 1st i have to pin the throttle to keep it alive as i slowly let out the clutch and the bike is pretty sluggish out of the gate.

ive been told that i should check out the ignition coil. ill check this with a multimeter but is there anything else i could do to help with this near-die situation when starting to move from stop?

 

wow your slide looked like mine. My 1996 XL 1200C would idle fine but when I hit accelerator it would die out . I had 2 problems 1 the intake gaskets leaked i replaced those 2 rebuilt the carb with cv performance parts still there was a problem. I spoke with local Harley dealer mechanic he said to replace the carb as he had since this problem before as thee maybe a problem with the body of the carb somehow warping over time and causing a small enough leak to cause an atmospheric pressure issue. SO i bought a decent carb on ebay for 100 buck and rebuilt it. It runs great now

 

Check for codes, and check the Crank Position Sensor.

 

ive gotten to the point that i may consider a new carb.
i was told, and saw a video, that my problems may be due to my ignition coil. when i tested mine, the coil wasnt firing out of every tower, so i bought a new one. well now the engine doesnt go. itll turn over, but no engine. on my second try i think i popped a fuse, so now i have to address that!

i have also heard about the crank position sensor, but i was told that i probably dont have one in a 2001 sportster. do you know if this is true?

codes...i need to get familiar with these. would they display in the odometer? unfortunately my speedo doesnt tick, but the mileage is shown, but it hasnt moved so i know its not reading. maybe itll still display other info? doesnt changed when i hit the button on the back of the speedo though.