So about two days ago I noticed a new and worrisome noise coming from the engine-it's a high-is pitched whirring noise. It's difficult to describe in words. It's most notable once the engine has warmed up- especially once passed the point where the radiator fan kicks in. It's most notable from around 3000 rpm upwards. I have no idea what it is, but my dad says it sounds like bearing.
If anyone can identify the sound or give some advice as to what might be the cause, please help. I've taken a short video clip that hopefully highlights the noise that I'm talking about. Note the radiator fan is also on in the clip- so just ignore that as a noise source.
Tell Dad bearings internal to the engine don't whine when they go away, they knock. Bearings in trans, etc. usually grind when they go.
This has the sound of an accessory. It doesn't seem connected to engine rpm so that rules out something driven by the engine, like alternator. Open the fuel tank and see if that changes the sound. Check your fuel tank breather vents for blockage. My money's on the electric fuel pump. You might pull it out and clean it's filter out, as cloggage is no uncommon on these things, when a few miles get on. Mine was completely occluded with about 6500 miles on my 07.
Thanks for the replies. If it's not a bearing then it's good news (I guess). I'll check out the fuel tank, filter and pump thanks.
Regarding the cam chain tensioner, it was the first thing I checked. Removed the tensioner, reset in and installed it again. Turned the motor by hand and I heard it go to max tension. So I don't think it's that. After I did that, the engine actually had a rattle when cold that it didn't have prior. But the rattle quickly subsides when the motor heats up a little.
Bit of an update. I checked the generator/alternator- it's still like new. Also had the airbox off and the engine cover open. Couldn't see much and didn't actually help though- reason was a fellow at work said the cam chain wears on the gears- luckily I had a rather large bag of salt handy... :
Apart from completely disassembling the engine in search of whatever is making that noise, I still have no idea.
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Motorcycle: '99 GSX-R750-SOLD for '13 Kawasaki KLR-650
Re: Strange engine noise
Did you take his advice with the salt, or hit him with it? I would have recommended both.
If it changes in pitch immediately in sync with the engine as you rev it, it's mechanically driven- alternator, timing chain (both of which you checked), water pump, oil pump, or possibly even a vacuum leak sometimes, though those typically lag a little bit behind the mechanical parts noises, at least on car sized engines.
If it changes a bit, but lags behind the engine a little bit, see if it changes pitch when you go from all lights off to brights on when the bike's rpms are stable- for example, rev it to 2 to 3k, hold it steady, and toggle the high beams while listening for a pitch change.
If it changes in time with you hitting the brights, then it's gotta be an electric motor. Only ones on a bike are the fan and the fuel pump. If it turns out to be none of those, congratulations! You've caught a gremlin.
Welp, about to piss on over to the KLR adventure forum due to a change of steed. When I can afford a good GSX-R, I'll be back- I don't have time for fixing rat bikes anymore.