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Discussion Starter #1
The last 1000 miles or so I've had a crank bearing noise. It's been getting steadily worse, and my dealer is aware of it. The deal is once is gets so bad I can't ride the bike they'll look at it under warranty.

I haven't ridden two up for a while for various reasons, then yesterday me and my better half went for a ride out locally, she commented that the bike sounded terrible, with, "someone hammering on the engine cases from the inside trying to get out" is how she put it, adding, it's much louder than the last time we went out on it together.

Today we went out again, I accelerated from low revs a couple of times, not lugging the motor too hard, and the noise is now all but gone.

WTH is going on???
 

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Yesterday you were riding your Harley, today you were riding the Voyager! :)
(sorry, couldn't resist)
 

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How long does the noise persist? If you ride for an hour does the noise continue? The oil can drain down from the top end and take a moment to pressure back up. But if the noise persists more than 10 or 15 minutes; it could be indicative of a problem. If that's the case, I might push the issue with the dealer to have that top end checked out.
 

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It sounds like a bad idea to wait until it's too bad to ride. I would make the dealer look at it now. The last thing you want is for the engine to seize while you are riding.

Bearing noise is asking for failure.
 

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Discussion Starter #6
How long does the noise persist? If you ride for an hour does the noise continue? The oil can drain down from the top end and take a moment to pressure back up. But if the noise persists more than 10 or 15 minutes; it could be indicative of a problem. If that's the case, I might push the issue with the dealer to have that top end checked out.
The noise is worse when the engine is hot, presumably due to thin oil.
It is at its noisiest when the engine is under light load, at just under 2000 rpm, but can be heard at light load at almost any revs.
Spin the engine up hard and it quietens down, which are the classic symptoms of a crank bearing as opposed to a big end bearing which gets worse with engine load and an increase engine speed.

It is not top end noise.

The only other thing I think it might possibly be is noise caused by carbon build up on top of the piston. I had this once before, years ago on my very first bike, and I stripped that myself to clean the carbon off and the noise stopped.

However, like I say since a couple of top gear roll ons, the noise has now diminished somewhat, but it is still there, which is unhelpful because it had just got bad enough to take it in for the dealer to investigate.

I do not want the, 'Oh they all do that Sir' scenario.
 

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Discussion Starter #8
Been to the dealer today.
Looks like its just the plastic alternator cover reverberating at certain revs.
How stooooopid do I feel..........
 

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Been to the dealer today.
Looks like its just the plastic alternator cover reverberating at certain revs.
How stooooopid do I feel..........
Good to know, glad it was simple!
 

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Of course I thought my noise was just something vibrating. But when I inspected the entire bike I knew it was internal. Now the engine is getting torn down and rebuilt due to the KACR flying apart and going everywhere.
 

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And here I was going to suggest it was that plastic thingy ma-jig by the round shiny thing a-ma-jig. But I guess that could be mistaken for the alternator cover too. Glad you found the issue, seems these V-twins vibrate just a little. We have to check all those nuts and bolts now and then to make sure they are tight still.
 

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Discussion Starter #14
Well I'm still not convinced.
It's done a thousand miles now with the noise, and I guess any bearing failure would have got worse in that time.
The noise certainly diminishes when you brace the plastic cover, but it wasn't lose. I note on the schematic that this cover is mounted on two dampers of an unknown material, maybe they have hardened with the heat.
 
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