Hi all , i have recently noticed my bike dosen't rev out. In higher gears it holds back at about 11500rpm.
I have fitted a new fuel filter, checked the fuel lines and tested the fuel pump.
My speedo has had the disc cut back so i assumed its not the cdi cutting in.
Do i need to do the resistor mod to the loom? or is there something i've missed?

Have the carbs been fiddle with - sounds like it may need the jetting looking at - does it happen in all gears? or just at load in the higher ones?


Welcome to the site

Yes the carbs have been jetted. The bike runs fine in the lower gears the problem is in high gears under load.

So what was done to the carbs?

It would be fuelling related I reckon - running too lean? Has anything changed on the airbox/filter?

Foam filter, 108 main jets (should be 105) needles have 2 washers, longer springs in the slides.
The air box is missing the metal cage pieces in the snorkels. I thought they were just for sound dampening.

You are way to lean for sure .. email me for the correct size main jets you need - couple of items I need to check with you first.

Plus longer slide springs could be coil binding and slides not lifting properly.

Cheers

Looking at the problem in another direction / covering all bases - check your gearing is standard

Yes gearing is standard,
the power literally stops at that rev range as if the spark is being cut or its being choked, speed wise it's about 100mph. I've set the speed light to come on at 80 so was wondering if there could be some problem with the de-restriction/cdi.

I thought the speed light was part of the restriction to show when its being restricted causing the ignition to cut.
Youre better just doing the derestriction resistor mod

The speed light would normally come on at about 50/60 its activated by a stepped metal disc that passes through a sensor. There is one step for the light and another for the limiter. If you remove the upper step (by cutting/sanding) you remove the limiter only. I think that's right if not please let me know.
I'm thinking that it's going to be the slide springs binding but i couldn't feel a problem when i checked them by hand.
What is the standard length?