Topic: CB400F Squeaky engine when warm

[Alaxy Galaxy]

I've got an issue when the CB400F gets warm (20min ride or so). When the bike drops down to idle, I hear a squeaking noise pretty similar to a slipping accessory belt on a car. It may or may not be there at speed, but there are too many other noises for me to hear. The first time I heard it, I though it might be some loose exhaust nuts, so I parked the bike, went inside to get my tools and fired it up again (3 minutes max) and the noise was gone. I *think* it's coming from the front/timing area, but I can't be certain.

This may or may not be related, but despite my idles being steady at 1100 RPM, sometimes, when at a light, it suddenly drops and the motor wants to die. A steady crack of the throttle brings everything back to normal. It happens about once a minute or so.

One of my colleagues suggested that perhaps the valves aren't getting enough oil and that the springs get stuck..?

(video and audio are poor, but it can give an idea)

https://video-atl3-1.xx.fbcdn.net/v/t42.9040-2/37276115_247401192724627_1177500584534605824_n.mp4?_nc_cat=0&efg=eyJ2ZW5jb2RlX3RhZyI6InN2ZV9zZCJ9&oh=6c0fb5c2d879da6dbdcf3c087cedfa93&oe=5B50C1E7

[robvangulik]

The cam that activates the points should be greased now and again....

[Alaxy Galaxy]

Thanks for the tip, robvangulik. I did not think of that.

I put some Sony silicone VTR grease on there and I'll report back when I get home.

[Don R]

 A squeal can be a bearing going out, you could check the oil filter for silver flakes.

[robvangulik]

I like to start with the simple things...

[Bodi]

Check the clutch adjustment, mine squealed when it was too tight and spinning the throwout bearing with clutch engaged.It should be out of contact and not turning with the lever at rest.
Squealing is usually a bearing.
The field coil mat be hitting the rotor.
They do have a characteristic clutch whine - the straight cut primary gears, I think - but it is not a squeak sound.
Super overtight cam chain adjustment might squeal?

[PeWe]

Silicone and electrical connectors are not friends. Here the point contact surfaces that must not get any silicone. Better with lithium grease that withstand high temp.