my h reg nc30 has every now and again at around 11000 rpm held back just for a mo then cleared ,this is starting to happen more and more .the carbs i striped and cleaned before using the bike and its had new plugs any idea where to start to look ?

dom-tune wrote:my h reg nc30 has every now and again at around 11000 rpm held back just for a mo then cleared ,this is starting to happen more and more .the carbs i striped and cleaned before using the bike and its had new plugs any idea where to start to look ?

You mean it's got a flat-spot at 11,000rpm I take it (feels like all the power has gone for a split second?)

The standard NC30 has one at around 6800-7000rpm.

Being that high up is a little strange as thats on the main-jet.. although an aftermarket can / system if you have one might alter it.

Dyno time would be the easiest way to sort it if you can find a skilled dyno operater familiar with these bikes (somebody on here will be able to recommend)

The standard cure for the normal flat-spot is raising the needles 0.5mm with an extra shim washer.

I suspect your battery voltage may be a bit low. Had this in the past.

Good call.

Check the electrical system first

thanks i done the shim job on the carbs .wiring on the bike was very bad when i got it ,loads of stuff just twisted together and melted .i will have to go over it again by the numbers .

thanks again chaps

dom-tune wrote:thanks i done the shim job on the carbs .wiring on the bike was very bad when i got it ,loads of stuff just twisted together and melted .i will have to go over it again by the numbers .

thanks again chaps

Did you try it without the shims