FUEL ISSUES WITH CARB..

Wasted spark system. If fuel and electrical is all good/correct it is often the case in these symptoms that motor cycle spark plugs that although looking good and firing outside of the engine are breaking down and will not fire under compression pressures on a power stroke but will fire unburned fuel on the unpressurized exhaust stroke when the plug again fires in a wasted spark ignition system and when so firing the result is a backfire, usually quite loud.

A 2003 model with only 50 miles?? Wow....well,since youve already taken the carb apart and cleaned it,did you hook up the vaccum line for the VOES switch on the intake manifold? If so,..when you get the bike running,..spray some brake clean around the intake where it bolts to the heads.If the idle picks up,or starts to sputter,..youve got leaking intake gaskets. Which is a good possibility on a bike that old with that few miles on it.The choke essentailly adds more fuel to the motor,and by what your saying,the bike is obviously running lean. Also,...im ASSUMING that you have fresh gas in it,and the petcock is turned on.

Squirt some fuel directly in to the chambers past the carbs. If she fires up then you have a problem with the fuel system. Check the valve on the tank, pull the hose to see if it flows fuel. If not it is clogged up or some models have a vacuum hose that opens the valve. If you are getting fuel to the carbs but no start your carbs need cleaning, if she starts with fuel squirted right into the cylinders. Hope this helps FixYa up.

No, nothing else to check. You need to completely disassemble the carb and clean it out. When gasoline left in the float bowl evaporated, it left behind the gummy additives that the refinery puts in the gasoline. This mess has clogged the jets and small passageways in the carb. The reason it runs with the "choke" out is that it is not a real "choke" but rather an "enricher circuit". It has it's own air passageway and fuel metering "jet" in the float bowl.

Good Luck
steve

If all the lowering has been done in the rear of the bike, then your transmission/primary lubricant level may be too high back where the vent is located. If so, I'd be willing to bet that your reserve position on the fuel tank won't take you very far either. If the bike has been radically changed from level ride configuration, you must adjust the fluid levels in certain areas. Back when people would extend the front ends drastically without raking the frame, they had major problems with these issues. One other thing that will do this is fuel getting into the engine and primary case. I once saw a Sportster that the needle and seat was leaking in the carb. It filled the engine with fuel and it seeped over into the primary though the sprocket shaft bearings in the case. Smell of your oil and see if it has gasoline in it. If so, fix your carb and make sure you turn your fuel off whenever you turn the engine off. It's old school but it works.

Good Luck
Steve

There was a way the drag strips used some sort of instrument to determine the displacement of an engine without a teardown. Seems it was called a P&G tube or something like that. I've never seen one. The only way I know of telling if your engine has be bored to the 1200 cc. piston size is to take the head off of a cylinder.

The S&S carb is an old design but it's simple to tune, that's what most people like about them. The CV type carbs are much better but American riders don't like them much. Although Mikuni is making headway under the Screamin' Eagle trademark.

Now, if you bike was orginally and 883 and it was converted to a 1200, there are two ways of doing it. One, was to buy a complete kit with pistons and heads. The other was to bore the original 883 cylinders and use the original 883 heads but the pistons had to be special drop top type pistons to keep the compression to a reasonable amount. The combustion chamber of the original 883 heads are much smaller than the chamber in the 1200 head. If you don't use the special pistons, you won't be able to keep head gaskets on the engine. Wiseco makes the pistons for the conversion.

As long as the engine is running good, don't worry about it.

Ride Safe
Steve

you might need to clean you stator(altinator) or maybe get a new one for you spark to work right if you have already changed the coil.also bad gas can do it also or low fuel.when the tank is low put your bike gas valve on reserve.A friends bike was running badly and all i did was put it on reserve cause the tank was low and the bike ran great after that.

Remove the carb soak in carb cleaner, **** out small bleed holes with a wire from a wire brush etc. One of the passageways is still clogged, or the float is sticking.

Had your bike sat a long time without being started? Been down real bumpy roads? I worked on a friends 1999 883 Sporty recently, it needed the carb rebuilt. I cleaned out all jets and passages, and float level was reset, it was out of adj.. Also, when diagnosing bike hard starting and backfiring out the air cleaner problem, I found the timing plate had losened up and the timing was off about 7 degrees which I adjusted back to spec before I rebuilt the carb. The plugs were also clean, not dry..Runs Good Now. The shop 1st looked at bike before I did, they said it was an Ignition problem and changed out the key switch which did Not solve problem.