Normal choke position in Honda 100 bike.

Step one, is petcock open? And what exactly do you mean by "dropped in revs?" Did it happen suddenly? Or was it the normal drop after the engine warms up?

hi
i do not know what motorcycle you have ?
but i detect you may have a choke problem
some motorcycles have a manual choke
and some have an automatic choke

automatic choke comes on with the ignition and
goes off when the motorcycle gets to normal running temperature
hopefully it could be a just a relay that operates your choke
but the other problem with automatic chokes are
if the motorcycle is only used for short journey's
it does not give the bike chance to get up to normal running temperature
eventually the choke will seize up in the closed position
this will make it feel like the engine is choking out as you described
to repair this you will need to remove the carburetor's find out where the choke is
take it apart and clean it up and reassemble the choke mechanism and reassemble the carburetors
refit them to the motorcycle

if your choke is a manual choke
there is a good chance your choke is seized in the closed position
if so it means that the bar between your carburetors that operates the choke has seized
to repair this take the carburetors off
find the bar that operates the choke
and spray some fine oil and move it around until it frees off the mechanism
then refit the carburetors to the bike and give it another go

good luck
ride safe

http://www.bikebandit.com/houseofmotorcycles/2004-honda-motorcycle-crf150f/o/m2255#sch304256

Here is a schematic of a carburetor. All you need to remove is the bowl at the bottom to access the jets. The choke richens the air/fuel mixture and makes it easier to start, however under normal conditions you will foul plugs out by leaving the choke on. If your bike is running right with the choke engaged, and shutting off when not choking, then your air fuel mix is too lean. = not enough gas. You are right in wanting to clean the jets. Hope the schematic helps.

Possibly you used bad quality fuel, got water in the carburators or some piece of dirt.
1. Try getting the gas you have in the tank changed completely.
2. Cleaning the tank is also advisable.
3. With a new fill in the tank try revving the bike or even taking it for a ride with the choke in action.
4. Check the carburators.

If the spark at the plug is goog then its a fuel or choke / air problem .Check to see if the plugs are wet after turning over the engine a few times .you may have a sticky choke that not letting enough air in with the fuel mixture .

Try a fuel additive to clean the system, also if the airfilter is dirty or damp, this can cause problems.
You may even have a rust problem in the barrels.
Or even the engine oil may have thickened causing a resistance in the crank bearings, so flush the engines oil ways if other solutions don't work.

The problem is an air leak leaning the fuel mix. The idle speed starts going up a ramp until it is wide open. The valves no longer seating well is a possible cause as is carb manifold gaskets, rings and a cylinder head not torqued down tight.

make sure you have air filter. raise the needle some so you get more gas.