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I've got a '95 Katana 750 which I picked up about a month ago and have since put about 1500 miles on. The thing is my first sport(y) bike and has been an absolute hoot. I love it. :thumb:

Anyway, the bike has recently starting making a slight griding noise (for lack of a better word) when it is in gear and moving. The noise is obviously coming from some revolving part as its frequency increases directly with road speed. It's independant of engine speed, however, so it sounds the same at 30mph in 2nd gear as it does at 30mph in 4th gear. It's not a terribly loud noise and it sounds similar to a wire brush just lightly brushing over another metal surface. It's just sort of a brushing/grinding sound and I don't know how to explain it better than that... Noises are pretty hard to explain, aren't they? I can also *just* feel it in the footpegs but it's nothing crazy - just a slight roughness in tune with the noise. The bike's geometry, stability, and feel are otherwise unaffected. There has been no appreciable loss of power, either.

Other details: It ONLY makes the noise while moving in gear. Coasting with the clutch pulled in results in no noise making me think it can't be related to wheel bearings, the chain and sprockets, or anything in the drive train after the tranny. Since it's independant of engine speed and gear, I don't think it's the tranny or the clutch, either. But what else could it be? :confused:

Sorry for the long post but I had to give as many details as I could! So, have any ideas as to what could be making this noise?
 

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I wouldnt discount the chain just yet. It tends to be the reason for 90% of the strange noises bikes make. It might not be the case here, but its the easiest to check.
Otherwise I'd say its the clutch. or some body fairings rubbing against something
 

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Discussion Starter #3
I'm planning on replacing the sprockets and chain very soon anyway so, if that's the problem, it should be taken care of.

What I don't get, though, is how the chain could be responsible for the noise when the bike is completely quiet when coasting out of gear. The chain and sprockets are (of course) still turning then. I suppose it could only make the noise when there's tension in the chain...

Maybe I should just go ahead and replace those parts right away. Couldn't hurt, could it?
 

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I was thinking it had something to do with tension in the chain. Its really hard to say without looking at it. Check closely that you dont have a piece of fairing rubbing against the tire, or something stupid like that.
The worst scenario is that you got something wring deep inside your tranny.
Do you have a stand? or a center stand? Lift the front wheel in the air, start the bike, in gear, and start looking for it.
 

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It's your chain. The reason you don't hear it when coasting is because it is always much louder when the chain is under load.

As chains wear they develop a tight spot. You can still get quite a bit more use out of your chain by keeping it well-lubed and adjusted on the loose side. When adjusting it, make sure that you are on the tight spot. It can be found very easily with the back wheel off the ground and the bike in neutral. Spin the wheel slowly with your your hand while watching the bottom run of the chain from wheel to countershaft. You will actually see the chain move up towards the swingarm when you hit the tight spot.

Having said all that, it's best to replace the worn set. The bike rides & feels much better with a good chain & sprockets............
 

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I go along with the words in Rundog's post as so many, new to m/cing do not realize what a woren chain is like, the loose spots, the tight links, the pure slop in the chain OFTEN giving the rider the impression he has a faulty clutch. Yet it could be the sprockets though I put my money on the rear chain AND how it has been serviced by the prior owner(s).
 

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I'll offer another hypothesis, ignoring for a moment your coments about the lack of noise when coasting in neutral.

When brake pads become worn, tiny wires protrude from the pad, and drag against the rotors, producing a very annoying sound, designed to attract your attention to them.

You didn't comment on what happens to the sound if you apply the brakes.

Have you checked your pads?
 

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Discussion Starter #8
As an update, I retensioned the chain last night and added in a good deal of slack (relatively speaking). The grinding noise almost completely faded away though there remains a slight noise in the same pattern as the original sound. It's not so much a grinding anymore as it is a hum that gets louder and softer in a cycle. I chalk that up to a very tight spot in the chain which screamed its existence at me when I was messing with the tensioners and oiling everything up.

The real issue here is that I need a new chain. I knew that when I got the bike and now I really know it. The red, powdery, dried up lube is starting to show up, too. It's new chain time! The only question now is if I stick with stock sprockets or go +1 -2. :D

I consider the problem solved. Thanks for the help, guys! :thumb:
 

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I'd stick with stock size sprockets (You still need new ones). Changing the final drive does make the bike a tad easier to wheelie, but also harder to control. So you dont gain jack, but put more wear and tear on everything.
 

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I had a sound that was grinding and rythamic... comming from the front sporcket it was also when I need to change my chain and sporckets.... to my amazement I found that the nut holding on the front sprocket had backed off and was grinding on the case that covers it...... :eek: After changing the sprockets/chain and loctiting the nut it is smooth as silk.

If we hook up this week I can take a listen if you want. I also noticed that when I rode it for a min or so I couldn't even touch that cover it was soooo hot from all the friction.
 

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mainerdr said:
If we hook up this week I can take a listen if you want. I also noticed that when I rode it for a min or so I couldn't even touch that cover it was soooo hot from all the friction.
Like I said, the problem seems to be solved now that I loosened up the chain. I still need a new one but with enough oil, I'll be able to keep going until the new one arrives. I'm planning to order it this afternoon so hopefully it'll be here by the weekend.

You can still listen to the bike if you want. I've got no problem with that.
 

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I have had customers that use to come to our shop with very long faces feeling for sure it was the clutch as even take-offs were lousy.

In most cases is was the chain & often it was the chain only once we looked at the sprockets we could see some hooked teeth & some even rounded off tell us a number of time the chain even hopped over the sprocket.

Back in the late 40s to early 50s & even later on in the 60s the clutches were pretty lousy. These days a clutch has a long life unless the rider has been stunting with it.

I had a 250 Observed Trials with so much torque in it that the light stock 428 chain was woren out in no time & yes in sections I could hear & feel the chain actually pull OVER the sprockets. As I was having special sprockets made so I could use a 320 chain & that was the end of my problems. Well actually the bike, once finished was not 246cc but 321.5cc with extra crank port in the piston & extra 6.5 lbs of outside flyweel weight. YET the clutch stood up to all I could give it.
 

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I've got a '95 Katana 750 which I picked up about a month ago and have since put about 1500 miles on. The thing is my first sport(y) bike and has been an absolute hoot. I love it. :thumb:

Anyway, the bike has recently starting making a slight griding noise (for lack of a better word) when it is in gear and moving. The noise is obviously coming from some revolving part as its frequency increases directly with road speed. It's independant of engine speed, however, so it sounds the same at 30mph in 2nd gear as it does at 30mph in 4th gear. It's not a terribly loud noise and it sounds similar to a wire brush just lightly brushing over another metal surface. It's just sort of a brushing/grinding sound and I don't know how to explain it better than that... Noises are pretty hard to explain, aren't they? I can also just feel it in the footpegs but it's nothing crazy - just a slight roughness in tune with the noise. The bike's geometry, stability, and feel are otherwise unaffected. There has been no appreciable loss of power, either.

Other details: It ONLY makes the noise while moving in gear. Coasting with the clutch pulled in results in no noise making me think it can't be related to wheel bearings, the chain and sprockets, or anything in the drive train after the tranny. Since it's independant of engine speed and gear, I don't think it's the tranny or the clutch, either. But what else could it be? :confused:

Sorry for the long post but I had to give as many details as I could! So, have any ideas as to what could be making this noise?

Have you tried lubricating the chain. Worked for me. I had the same gnarly grunt through footpegs and was wondering if the transmission had shot. Just lubricated the chain and no more grinding through footpegs.
 
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