The bike is misfiring. Starts ok but in no time it cuts out on number 2 cylinder. Seems to be throwing more petrol in than the engine can cope with. You can actually touch the frontpipe after it's been running but you can't with the other 3 as they're too hot

plugs will not spark under compression if they are faulty or the HT lead id off too high a resistance. or mixture is incorrect
In the real old times when plugs were cleaned and tested one of the tests were to test spark in a dry compressed air chamber where if there was a problem they failed to spark
as you have fitted new plugs it comes back to the ht lead
they are carbon tracked lined internally, the connection for the plug and cap is just a steel pin shoved up into the carbon track
try using copper ht leads where the copper wire comes out to the connection
there could be a valve seating problem or weak valve springs on that cylinder that is not allowing proper seating under compression
if you have 2 carbies then the float level for that cylinder may be too low and under load starving for fuel

replace no 2 injector

I woud say the ignition timing has not been adjusted to cope with the new pipes.
Consult the manual for adjustment procedure.

I think it means that the number one cylinder is misfiring, which could be spark plug, coil, the plug wire, or the injector. Usually, if the injector is at fault it will have a code for that. Take the spark plug out and check the condition of the plug. If the plug seems alright, swap it with the number 2 spark plug and clear the trouble codes. If the plug was at fault, the computer should throw a code for cylinder 2, if it still throws a code for cylinder 1, then it may be the coil, If the engine has a distributor, change the distributor cap and rotor.

P0301 Cyl.1 Misfire Detected see if its throwing another code now instead of cyl 1 may be another problem code now

you may want to go and have your coils looked at. the first thing you should do though is pull the plugs and see what shape they are in. the plugs will tell you everything about your engine and what it is doing and when. if your plugs are good then go have your coils inspected. do not try this yourself if you do not know what you are doing. there is a very high chance of very high electrical discharge to you. it may even kill you if it hits right.

has this model got a conenser if so i would try changing that, sorry 2006 model

The mechanic should use or do this ,"engine lubrication ".cleaning the engine while fixing the engine .If the problems in the multi cylinder, then its the piston and the piston rings. Replace the destroyed or worn out piston rings.then check the crank shaft and the cam shaft for for assurance .then set in timing for ICPE ,icpe is the intake, compression ,power and exhaust.then check and arrange the engine valve.the mechanic should use filler guage for the valve .the misfiring ,check the carburetor or fuel pump throttle.may be its stuck.In High speed auto-diesel mechanic , trouble shooting is what we always encountered while studying .But its not just engine but even car electrical problem.headlights , fuses and other electrical parts of a car.But its seems that the problem of the car is not electrical problem sir , good day sir.

Make sure your fuel tank vent is not plugged. To see if this is the problem, the next time the bike starts acting up, stop and open the fuel tank. If you hear a whoosh of air being sucked in you know your vent is plugged.

The C8HA is still available, it is NGK stock number 2168.
Good luck.

fill up the gas tank and add some fule injector cleaner
that solved my problem with misfire in cylinder 1
took about 2 days and my engine light went back off
i used a brand called
lucas fuel injector cleaner
i got it from advanced auto
auto zone also carries it