NC24 Issues

[Sidmire]

Hello guys and gals had a few problems recently with my newly aqquired NC24 usually i can pick up on problems pretty quick but i have not bothered to ask anyone about it so was wondering if anyone could shed some light on it here goes when i start the bike up it starts first time everytime and when it gets warm it seems to either idle at about 1200RPM which is pretty lumpy and then the revs will rise then drop again now it will either keep running or it will die as though it is sucking crap into the carbs now im not one to go digging unless i have to and im certain there are no air leaks so would anyone recommend taking the carbs off just to give them a clean because from what i can see the carbs have never been removed and it also has a nice SCORPION Race System so could this perhaps upset the standard running system and would i have to jet up cheers

[Neosophist]

Hello guys and gals had a few problems recently with my newly aqquired NC24 usually i can pick up on problems pretty quick but i have not bothered to ask anyone about it so was wondering if anyone could shed some light on it here goes when i start the bike up it starts first time everytime and when it gets warm it seems to either idle at about 1200RPM which is pretty lumpy and then the revs will rise then drop again now it will either keep running or it will die as though it is sucking crap into the carbs now im not one to go digging unless i have to and im certain there are no air leaks so would anyone recommend taking the carbs off just to give them a clean because from what i can see the carbs have never been removed and it also has a nice SCORPION Race System so could this perhaps upset the standard running system and would i have to jet up cheers

You shouldn't need to alter the jetting, besides Jets only come into play after around 7000rpm.

This is all idle circuitary. It sounds like classic air-leak to. I've had it on several VFR's. How have you tested it for air leaks? Often the rubbers can become hard and brittle and never seal properly.

Some pointers to look at:

Each of the cylinders has a balance take-off screw and washer on it on the NC24, make sure they are all tight and not leaking air.

The fuel vaccum pipe comes from cylinder 1 (rear left) and is partly obscured by the frame, this can be another air-leak point, if it's old, for the price usually best to replace this pipe..

The charging systems are a weak point on the bike and electrical issues sometimes do cause strange running (doesn't sound like it in your case but check the charging system over while your poking around, best to verify its ok before it dies on you)

Most likely it's another old neglected bike.

Take the carbs off, clean all the passageways thorougly.. the idle circuits are very small and block easily with old crap, this will cause shitty running.

While the carbs are off do the valve clearnaces, there lock-nut adjusters not shims on these bikes so it won't cost anything but time, and can save a lot of costly damage and give better running.

Once the clearances are done, refit the carbs and balance them.

the 24 should have 115 jets all around, 35 pilot jets, 5 hole emulsion tubes in the rear, 4 hole in the front, set the float heights to 6.8mm and the pilot screws to 2.25 turns to start with.

[Sidmire]

Cheers did have a problem in which today it failed to start in other words it ran out of power charging system is fine ie when you give a small rev whilst idling the lights do brighten so i know there is a problem with the battery and im going to take the carbs off tomorrow and give them a clean might have a mosey at the clearences as the last time i touched a set on a Z250 i kinda broke it but its part of the learning curve :)

[Neosophist]

Cheers did have a problem in which today it failed to start in other words it ran out of power charging system is fine ie when you give a small rev whilst idling the lights do brighten so i know there is a problem with the battery and im going to take the carbs off tomorrow and give them a clean might have a mosey at the clearences as the last time i touched a set on a Z250 i kinda broke it but its part of the learning curve :)

Always best to start with full choke and no throttle at all until it's running.

Brightening revs isn't conclusive proof that the system is in good order. Get a voltage test done on it to confirm it's outputting enough juice to charge the battery.

[dogmatic69]

Brightening revs isn't conclusive proof that the system is in good order. Get a voltage test done on it to confirm it's outputting enough juice to charge the battery.

my NC35 lights also dim on idle, and then brighten up when revving. Starts every morning at the push or the button, bit of choke no gas. Battery has not gone flat in the two months I have been riding (mostly in the dark with the bright beam on). Get the volt meter out :)

[Sidmire]

Cheers all just finished working on it then the non start issue was due to a wanked battery its been rectified as for the clearences they have all been checked and i have cleaned the carbs with parrafin so there looking like new all the jets are clear and its idles like it came out the factory just a case of fitting a new clutch cable and im back in business :)