I've posted about this before.

I have a rumbling noise that I think is probably a bearing. The noise is coming from the front of the bike and is significantly more noticeable on over-run. If I pull the clutch in, the rumble continues, if I apply power the noise reduces/disappears.

The front wheel bearings are 4 months old and as far as I can tell are smooth.

Last time I posted on the subject, I was advised to reduce the chain tension, I did this and it helped, but I had to set tension at 2.5cm which is max according to the Haynes manual.

I need to have the chain really slack now for it not to make any noise, which causes nasty gear changes

The chain I have on there is a good DID X-link but it's only 112 links, has this ****ed up the main drive bearing do you think?

 

try lightly applying the front or rear brakes while coasting and see if that makes a difference in the noise.

 

I'll give it a go this evening Tobiahr. Thanks for the suggestion.

 

Hawk ... have you checked that the front sprocket hasn't come loose? I've had that happen in the past! Also, while you're in there, check the front sprocket carrier bearing for wear?

 

^^^^^
That's my next port of call Shakey. I'm sure it was pretty tight when I changed the chain last time, but who knows and as you suggested I'll try spinning the sprocket bearing to see if there's any notchiness.

Any idea how difficult it's gonna be to change if it is the bearing?

 

If it's the bearing STeve, you'll be doing a full bottom end strip down.
Engine out, crank case split. No other way.



Here's a picture of the complete gear train with the cases split. I'm afraid if yours is getting the grumbles you'll have to face this sight yourself. Don't panic. It's not that hard. You just need time.... and some cash for the bearings.
David Silver has them quite cheaply.
I'll pour the beer.

 

Jeeeez Henry ... That looks serious!

Let's hope it's a loose spocket?

 

Yep! Cross those digits Hawk!

 

But at the same time..... don't you think it looks beautiful?

 

As my old Mum used to say "a thing of beauty, is a joy forever!"

Just out of interest Henry ... How many miles had the bike done when it failed?