Gearbox noise "Whirring" in neutral

Hello
I'm running in my GT240 / Cyclone 5 set up. I was very careful to shim correctly and torque everything properly.
When idling in neutral, there is a noise from the kickstart end of the casing that sounds a bit like the kick start is engaging - like a "whirring" though, not a fast clicking.
Pulling in the clutch in neutral has no affect on the whirring sound
But when I put the scooter into 1st, with the clutch pulled in, the noise stops.
I do not think it is the kick start, because i cannot feel any associated vibration when I touch the kick start, and I have to move the kick start about 3/4 of an inch before the shaft is engaged , which makes a different sound fast clicking sound, and I can also feel the teeth of the 1st gear. Ive also removed the kick start rubber as a test and this has no affect.
I know things like this are hard to diagnose on a forum, but just wondered if anyone else has encountered this or know what it could be.
I'm running in my GT240 / Cyclone 5 set up. I was very careful to shim correctly and torque everything properly.
When idling in neutral, there is a noise from the kickstart end of the casing that sounds a bit like the kick start is engaging - like a "whirring" though, not a fast clicking.
Pulling in the clutch in neutral has no affect on the whirring sound
But when I put the scooter into 1st, with the clutch pulled in, the noise stops.
I do not think it is the kick start, because i cannot feel any associated vibration when I touch the kick start, and I have to move the kick start about 3/4 of an inch before the shaft is engaged , which makes a different sound fast clicking sound, and I can also feel the teeth of the 1st gear. Ive also removed the kick start rubber as a test and this has no affect.
I know things like this are hard to diagnose on a forum, but just wondered if anyone else has encountered this or know what it could be.