My Nsr mc16 has starting running on one cylinder, top one only, it's the bottom one playing up, sometimes it's fine and then it'll just cut out and it'll only run in the top cylinder then all of a sudden it'll cut back in again and carry on running normally ?? I've changed plugs, cleaned out carbs and it's getting spark ok so don't really know what else to try ?

It's strange how it just cuts out and comes back in again about 10 seconds later ?
Any ideas guys ? Thanks

Hi, I'm not an expert with NSR's but I would suggest that it is electrical.
Even though you are getting a spark at the plugs, it may be intermittent. It sounds to me like a contact breaking down somewhere maybe an intermittent short.
Carefully check and clean all the contacts in the ignition circuit....especially the connections to the ignition coils. If it then persists then swap the ignition coils (and plugs) and see if the problem changes to the other cylinder.
If it does then bingo. Ignition coils are not that expensive.

Of course, I may be well wide of the mark...but it's worth checking anyway.
Good luck.
Mike
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I don't mind dying...I just don't want to be there when it happens!

I would also install some new spark plug boots.
Jeff

Cheers guys ill try it out 2moro and ill see what happens. Thanks for your help

Could be one of the coil is not weking or not connected properly

i had the same problem before and it was the carb overflow pipe was blocked causing me problems.

have you compression tested both cylinders and did you clean your tank out at the same time as doing carbs???

Hi it's defiantly an electrical problem.
It's strange, one minute it'll be running fine then the bottom cylinder will just cut out and will stop working for about 15 seconds sometimes longer then will come back in and run fine for a bit and the same will happen again. When its running and it cuts out if I pull the spark plug cap off the spark plug until I hear it sparking to the plug it'll cut back in again and run fine with the cap loose but if I put the cap back on properly it'll run for a bit but then cut out again !! I just cant understand that when the cylinder isn't running how does it start running again fine just by me pulling the cap of the plug ?? It does this every time so isnt coincidence.
I've put brand new plugs in it and I've changed the cap so it's either the ht lead or the coil but its always getting a spark ??

You guys seem to know your stuff so do you have any ideas ?? Thanks again any help is appreciated.

If that was my bike, the very FIRST thing that I would do is make VERY sure that the battery is fully charged and that it doesn't suffer too much of a voltage drop under load.
Try measuring the voltage across the fully charged battery with the headlight on when the motor is not running. If it drops below 12 volts, then try another battery.
If you do not have another suitable battery, then perhaps connect up a good car battery in parallel using jumper leads.
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[color=#808080][size=9]Yes,.. I too know how to waste Time and Money,...

Just to explain myself; I think that it is an average battery that is causing your PGM to play up.
Possibly the capacitor (for one cylinder) in the Capacitor Discharge Ignition, is not getting enough of a charge (from the battery) between firing to be able to fire continuously.
When you remove the spark plug cap with the engine running, (which I do not recommend you do, by the way), the capacitor has time to recharge and will start to do its job properly again, for a little while anyway.
Possibly completely wrong, but just trying to help.
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[color=#808080][size=9]Yes,.. I too know how to waste Time and Money,...

Hi thanks for the advice ill try it later and ill see what the batteries doing. Cheers

Right I think I've sorting fixed it lol I tried the battery and put my car battery on it as well and there was no difference so I thought it could be the new plug I put in it so I put the old plug back in the bike and its been fine ever since but sometimes when i rev it and the revs die it seems to back fire but only on that cylinder ? It's certainly better with the old plug back in it and it doesn't seem to be going on to one cylinder anymore ! So I can only guess that the new plug I put in it was a duff one ?? Looks like I going to have to put another brand new plug in it and see what that does.

I've just had another thought when I took the new plug out of it it seemed to be very wet now I know this could be because it wasn't running right on the cylinder but now I've put the old plug back in, it seems to be ok but still not 100 percent and its backfiring on run over so my thought is is it overfueling on that cylinder which is causing the plug to foul and then not sparking right ? Just a thought, is there a way to tell if its overfueling ? Should of bought a four stroke lol

Bike has just started doing the same thing again going on to one cylinder with this plug ! I put another plug in it and its running fine again but for how long is any ones guess ! Does anyone have any idea as to why its eating spark plugs ? Cheers