Topic: cb400f clutch noise

[james mac]

Hi ive just finished restoring a 75 400f it goes well and is very reliable.thing is when i put it in gear there is a slight whurring noise from clutch area.ive done around 200 miles on it and its not getting worse.the bike had sat a lot of years prior to me buying it.anybody any ideas.info will be much appreciated.

[Bodi]

The whirring noise is from the primary gears. This is normal with the 400. With the stock exhaust, that driveline whirring is the dominant engine sound.

[camelman]

I love that sound!  I've noticed the 400f sounds like a modern four cylinder motorcycle engine mores than any other classic CB.

[crazypj]

400 has a primary chain tensioner and is much quieter than 500/550 (which doesn't)
Little things are probably more noticeable.
 If carb sync is good and everything is 'right' primary noise makes bike sound 'electric' 

[james mac]

The noise is there as soon as i put it in gear.if i release the clutch slowly it starts to whurr even though the bike aint moveing.

[camelman]

It sounds like it is coming from the clutch basket. Other than plates rubbing, I can't think of what it might be...other than a bearing.

C-man

[Bodi]

The primary gears drive the clutch basket - one small gear on the primary shaft and one big gear on the basket. Any load on these gears makes them whine, bike moving or not. When the engine is running the gears and clutch basket are spinning.