So I let my bike (1997 1200custom sportster, 5 speed) sit for three months and when I came back it wouldn't start. I have: replaced the battery(it had been going bad for awhile), done a spark test (good spark), drained the tank, removed the tank, filter looks clean, put the tank back on and put an additive to remove water with new gas. I sprayed the carburetor with carb cleaner and it'll run with the carb being sprayed but when i stop spraying it sputters and then dies. I am a new rider (<2 years) with very little mechanical knowledge but I can follow directions, i have rebuilt the transmission (with some muscle help). Any ideas on what might be wrong (fuel lines maybe) and how exactly to check this would be great.

 

Did the fuel you parked it with have Ethanol in it? Did you use a fuel stabilizer?

I'll be willing to bet you'll have to pull the carb apart...

 

Sounds like your carb is gummed up from sitting, need to take the bowl off and clear the jets and passages.

John

 

Sounds like the carb needs to be rebuilt.

 

What they said! You obviously have spark and it will run when you squirt staring fluid into the throttle throat; case closed. You have everything you need but a constant flow of atomized fuel being delivered to the combustion chamber or a "good carb". Gummed up from sitting if you have been honest and revealed all and have not already tried cleaning the carb... fairly simple but you have to know the specific settings for float bowl and what to do and not do (like poking pipe cleaners everywhere which could make things worse). Seems like you had a good enough grasp of TS so if you have a manual, take it apart and spray cleaner in all the passages (watch your eyes! wear eye protection!). Should run fine after.

 

This should help you with cleaning your carb.
http://www.m-thomasius.co.uk/?p=1810

 

If you still have the stock, vacuum operated petcock on the tank, make sure the vacuum hose is in good shape and connected at both ends.

But chances are, the carb is gummed up and needs to be cleaned and rebuilt.

 

I agree with all the above. As an additional point, I recommend you remove your new battery and charge it up off the bike, before refitting it. I know it probably says on the box that it is 'fully charged', but as you are having starting problems it will give you better service if you make sure it really is fully charged!

 

does this bike have a vaccum type petcock u may have a hole in vac line going to carb or even a bad petcock itself

 

So from all the replies I can see I probably need to clean the carb lol. Especially with the newest updated symptom. I pulled the vacuum line and the fuel line off the carb, drew a suction on the vacuum line and when the petcock was in on or reserve fuel flowed. The vacuum line certainly looks like it could be replaced but it still seemed to be working. I was really hoping to avoid having to do anything with the carb. I looked at the link above on how to take apart the carb and honestly I'm terrified I'll jack something up. I will try it if absolutely necessary but just wondering if theres any short cuts to cleaning the carb without taking it apart. I know the answer is probably no and it sounds like I'm begging for an alternate solution to an already diagnosed problem but I figured I'd ask. Thanks for all the help already.