NC21 Wont start after 1 year of staying

[demerdzhiev]

Thank you for the detailed answer, i am just having the float valves changed because still some of them flood the cylinders and they will spoil the plugs again. Since i am having the carbs off i will have the drill bit sync method done to them, hope it will work. About the other things i think i have already done them.

Will report after synchronizing them!

[demerdzhiev]

Another problem :D i am getting pissed off.

Soo it starts quite easy, but there si like zero power 1000-7000 rpm after that its hard to rev, only tried it in neutral at full open throttle. the idle changes all the time, at times its perfect then after i rev it it changes and the revs go down very slowly between 1000-3000 rpm. Few small leaks on the carbs, i think its the fuel suppy pipes, the ones with the o-rings on them (thats the smallest problem).

When i got it out for a try, it died after 500-1000 meters. Battery dead, couldnt turn it even once, just the indicators were on. So i charged the battery and its ok. Thouhgt it doesnt charge it. Found an old analog multimeter at the workshop. measured the baterry when engine off: 12-13 v cant tell for sure because its an analog one. Started the engine and it has gone mad. goes from 0 - 15 v all the time up and down up and down. So i guess the rec/reg is faulty ? or the stator?

So to sum up, the bike cant rev nicely ( might be because of the charging problem, not sure) and it doesnt charge the battery.

[richyrd5]

yes change the regulator as that sounds like it duff...carbs might need a balance as well,but check the fuel pipes to..good luck...

[magg]

You need to get a multimeter that provides reliable readings and then check the charging system and load test the battery. Unstable battery voltage, caused by faulty charging system or a dud battery, can result in erratic ignition and thus erratic engine running.

[demerdzhiev]

the multimeter provides reliabe reading i made the same measurement on the car and there is no such faults, it records constant voltage on the system. So the fault is in the motorcycle electric system.

[magg]

Your multimeter lacks resolution and you described it as " old" but if you are happy, I am happy. Battery voltage going up/down repeatedly is indicative of a dud battery. Rect/reg function is to chop the alternator output to keep the battery voltage under 15 volts. A good battery maintains the voltage at 14 volts between the rect/reg troughs. No battery capacity means no fill in between troughs. Your battery does not sound too good if you could not get further than 1000 metre before it went flat and a battery that has been fully discharged usually suffers permanent capacity loss that causes erratic electrical performance. With the battery that went flat connected, disconnect the rect/reg, does the engine start and run ok.

[demerdzhiev]

I couldnt understand your last sentence , sorry.

My idea was the battery itself should be good enough if its being charged by the generator it should not fully discharge while the engine is working. Doesnt that mean that the generator isnt charging , wheter its from the generator or the rect/reg.

[magg]

If the battery is faulty, then the charging system will not function correctly.

If the battery went flat after a 1000 metres, it sounds suspect. A battery that has suffered a severe discharge is also likely to be now suspect. Is the battery any good, you can try a load test or start the engine run it while monitoring the battery voltage, a fully charged serviceable battery should stay above 12 volts for sometime without needing a charging system.

Disconnecting the rect/reg will remove any potential rect/reg defect from the equation.

[Neosophist]

sort the carbs out first.. hanging idle is sign of air-leak.. did you put new rubbers on it?

next you need to check the stator and battery separtly.

use AC volts setting, disconnect plug with 3 yellow wires and mesaure voltage at 5000rpm.. should get 50v ac or there abouts.

next, reconnect plug and measure battery volage on DC volts at idle and at 5000rpm, it should be no more than 15v

if you were getting a bouncing reading it sounds like you have either a loose main fuse or loose multimeter connections.

[demerdzhiev]

So i found the plug, but one of the pins in the plug was oxidized / scorched and certainly isnt making contact.
Anyway how should i measure the AC voltage when i disconnect the plug. Sorry i am not really into electricity.