Slight miss & High Idle

[Funjunkie]

Hey guys.... i just got a very low miles, 6500mi, 01 Road King Standard with a carb. Bike starts fine but has a slight miss . Runs fine when under acceleration but has a slight miss at idle. The bike idles high when it gets hot. It has V&H Oval slip on's and I dont know if the previous owner rejetted . I have a hunch something is clogged but I dont know what. The bike had to have sat a lot with that low mileage. Any help would be appreciated.

[Dave63]

Originally Posted by Funjunkie

Runs fine when under acceleration but has a slight miss at idle. The bike idles high when it gets hot..

You have a vacuum leak. Check all hoses to the VOES unit, and the petcock. Stick a separate hose on the petcock and suck on it. If it doesn't hold vacuum, the petcock diaphram is ruptured.

[Blackdog 15]

might be the stock spark plug wires...they are cheapo 6.5 mm I changed my wires out to 10.2 mm aftermarket ones when I had a miss..What a difference..

[Funjunkie]

Thanks fellas. Ill start with the hoses. dont know what the VOES unit is. a little help? I do have a service manual. and should I shut the gas off before i put vaccuum pressure on the petcock?

[Funjunkie]

Just Curious... How would that diaphram get ruptured?

[vlade]

Originally Posted by Funjunkie

Just Curious... How would that diaphram get ruptured?

Pure old age if nothing else.

[vlade]

Originally Posted by Funjunkie

Thanks fellas. Ill start with the hoses. dont know what the VOES unit is. a little help? I do have a service manual. and should I shut the gas off before i put vaccuum pressure on the petcock?

The VOES (for Vacuum Operated Electrical Switch) is the old style trigger for the stock HD "V-Fire III" ignition on all EVO BTs and non-Sport EVO Sportsters. (By contrast TC88s and the '98+ Sportster Sport use the more advanced, superior "MAP Sensor" in place of the VOES). Essentially, this VOES switch has a small hose ("vac line" pictured above) connected between it and the carburator, from which it measures the level of intake vacuum. Based on this level, a signal is sent to the microprocessor in the ignition module, telling it to choose either of its two curves. The ignition module will choose a "retarded" or default curve for an engine under hard load or WOT, or an "advanced" curve under light load / cruising. The VOES signal on late model stock Sportster engines is set at approximately 4" of mercury.

(I outha say I plagerized the former)

No but when you put a vacuum on the petcock outlet gas will pour out if its working right relieve vac and it should shut off. If your gonna hold the vac and test for leakdown youd probably be inclined to shut it off eventually. ( if you ever disconnected the fuel line to carb in the first place)

[Dave63]

Before you worry about the prior stuff......

have you tried simply warming the bike up, turning the idle back to 900-1000, and then readjusting the air/fuel mixture?

[Funjunkie]

No Dave. Can you talk me through it? Keep it simple.

[Dave63]

Warm up bike. Ride at least 5 miles.

Bring back home.

Idle adjustment scew is on right side of the carb, when facing the air cleaner (front brake side) of the bike. Look between the aircleaner and the tank.....down in there.

Turn it to the left to drop the idle. Right to raise the idle.

Once down to 900-1000, you want to adjust your air/fuel mixture screw.

The screw is under the carb, towards the rear of the carb, od center of the bike. A little mirror helps to see it.

Turn it in (clockwise) until the engine begins to falter. Stop.

Turn it out (counter clockwise) and as you do, the engine starts to rev a tad faster and smooth out. Find the spot that it runs the best at, then go 1/4 turn out. Stop.

DO NOT do this unless the bike is warmed up, and never with the air filter off.

IF it (a/f screw) hasn't been uncapped, (covered at the factory) then you need to remove carb and remove the cap. See here.....

Carb rejet/mod