It coughs, it stumbles,it backfires.....WTF

[dthemic]

What do you all think of this. My skorp spent the winter with me in my livingroom. In the fall it ran fine, very well in fact. Before I brought it inside I drained the tank and ran the carbs dry. So tonight I put fuel in the tank, the bike started and at first would not run at all without the choke on. Now it will start and run but it stumbles, it coughs back through the intake, it backfires, if you blip the throttle the rpms hang up then gradually returns to idle.And it pops and sputters. What the heck happened? And what do I do next?I want to ride not f--- around.

[DEmark]

I bet it's got water in the fuel. There is a drain screw on each carb, drain the water out there. I used to have the same problem with my Skorpion, don't know exactly how the water is getting in the tank, maybe condensing out of the air...?

[DAVID THOMPSON]

ah yes you live in nice humid pittsburgh
and the tank condinsed moisture
drain the carbs and look at the filter if any

[dthemic]

Well, the tank was drained and removed from the bike in the fall.Both the bike and the tank spent the humid winter in the house with me. Fresh gas was put in tank last night before I tried to start the bike. I have drained out all the fresh gas,drained the float bowl and put more fresh gas in the tank. Still will not run right! I am at a loss...

[jbthumper]

might want to try cleaning/servicing the carb....it might have sulfur(white stuff) resedue from dried petrol in the system....

just my 2 cents...

[phoebeisis]

The pilot circuit is partially plugged.The star circuit is usually yhe largest diameter,so it generally plugs up last.The pilot is the smallest,it goes 1st-MJ second.You can get the bike started,and it will run,but it is too lean so it backfires,stumbles,kills( with no pilot circuit,it runs just on MJ circuit which is barely in play at small throttle openings).The pilot circuit is the pilot jet,and the tiny passageways that actually connect to the venturi.
If you are lucky,maybe you can just take out the PJ and blast it with spray bottle carb cleaner(watch out for your eyes),then blast where the PJ is screwed in.Might as well give the Start and MJ circuits the treatment while you are there.The carb cleaner is tough on plastic(float etc),so either be very careful,or immediately blast the area with water to wash the carb stuff off areas it shouldn't sit on.
If this doesn't work thake the carb off-disassemble-and use the dip carb cleaner for 1/2 hr or so( or twice as long as it says to on the paint can it comes in).Luck.Charlie

[Zap]

Couldn't have said it better myself!!!

Zap

[keithcross]

I might be talking rubbish here, but have you checed the diapragm in teh right hand carb. If its split/perished it might cause it.

Keith

[dthemic]

Thanks for your suggestions guys. Here is where I am at now. It has been pointed out to me,by a very insightful person, that last fall although I ran the carb dry I failed to remove the float bowl drain like I have in the past. So I did leave fuel in the bowl all winter...oops. So it seems as if the main jet is clogged or restricted. I tried filling the bowl with carb cleaner,draining it then doing it again and again. I even filled the bowl and let it soak for six hours then draining etc..etc. No improvemnt. Removed the carb and installed my stock carb and now she runs. Now I must decide if I should attempt to fix it (I know I can take it apart it's the identifing the problem and putting it back together that concerns me), try to find a local I can trust or send if off to Galen Miller from hence it came.

Good news my Skorp runs.... Bad news cold front and several days of rain predicted. That sucks.

Thanks