Hi i have an nc23, its a k model. Its running perfect below 5000 rpm but no matter what gear i am in, at 5000 rpm it bogs down and runs shit. it sounds like its misfiring or running on 2 cylinders. I thought it could be the speed restrictor so i cut the metal tab out. unfortunately the problem still persisted so i done the resistor mod and that didn't work either I'm starting to think the carbs need to be cleaned but i don't want to go at them in case its an obvious fix. Has anyone had this problem before? or can someone please advise me?

Thanks very much, Simon.

That deffo sounds like crap in the carbs. Blocked main jets I would say.....

Check them first because it's easy to clean.

thanks very much for your help, i'll have a look at them the weekend

Any other suggestions?

Still bogging?

to be honest i didnt get a chance to clean them. i went and bought a gold label CDI, its in the post atm. im going to throw in the new CDI, if it runs right then it was the restrictor and if its still bogging then i'll clean the carbs. I was curious to see if anyone else had any info on this. its wrecking my head.

Turns out it was the restrictor. i threw in the new gold label CDI and she ran perfect. thanks for the input (Y)