The bike wont start all the time and tkes 20 min to warm up

Check your ignition coils. Sometimes they fail with an open circuit, this can sometimes close up when the machine is cold and open again when it heats up. So. it will start when cold and fail when it warms up.

I am having trouble with your english translation of the symptom. However, if your bike starts and runs fine once it is warmed up and initially starts fine in warm weather this indicates a clogged choke circuit in the carburator and will require a thourough and proper cleaning of the carb.

Disconect battery for 5 mins reconce after time should do it for you should start.

try turning the choke on,which is on the left handle bar next to the grip,leave on ,twist throttle full then close it,press start button,should start,let run for a few mins then turn choke off,

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Probably electronic ignition module or coils going bad when getting warm. Check and replace as needed.

Check the temp sensors on the engine, if they give a bad reading it will make the engine run poorly, be hard to start etc... Take car to garage and get them to run the diagnostics on the computer, I reckon it is a temp sensor that only works when it is warm...

voltage regulator or bad alternater in the mornings check to see if the alternater is warm before you start it if it is the alternater is draining your battery

Try putting in new, stock spark plugs. Check and possibly replace the air filter. Charge the battery. Get the bike running then check the battery voltage at 2000 rpm. It should show 14volts or more. If not, get the charging system checked. Get a can of starting spray (for future problems).

Get the compression checked. Your bike is 21 years old and I will bet that the valves are needing to be reseated. Check the valve clearances with a cold engine and reset valve clearances as needed. Check the area where the head contacts th cylinder. Any mist of an oil stain? Tighten the head or replace the head gasket. If replacing the gasket, now is the time to have the shop lap re-seat the valves. Have them sync and balance the carbs as well. Your bike will now have its' manners back and show you the dedication it should.

The heater will not work.Do you pull the choke cable?Is your carb assemblies cleaned and adjusted properly?I assume that your fuel pump works fine.