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I own a TVS Apache RTR. Recently I have started to hear grinding sounds from the gear box. When I showed it to a authorised service centre, says that it's due to the sprocket being damaged.

But the thing is even if the chain is loosened, after 100kms again the chain gets so tight that the rear wheel doesn't even rotate unless rotated very hard.

My questions are,

  1. Why does it keep getting tightened every time?
  2. Does the chain sprocket has to do with any of this?
  3. If yes, is it required to replace the rear sprocket as well?

Edit: On looking closely at my chain I see that the Centre portion of the chain looks like it has been scratched. I can feel the roughness.

I got the chain cleaned and oiled. It became sufficiently loose again. But the sound is still there.

Update : Chain cleaning and oiling reduced the intensity of sound. Changed the engine oil. Oil level was quite low. Added new synthetic oil (Grade 20W50).

Observation: The intensity of the grinding sound increases after riding the bike for around 30 kms on a highway, which is my daily one way commute. The intensity lowers when the engine cools down. can there be any misalignment in the gear box causing to amplify after expansion due to heat.

Just want to get it verified before asking the mechanic to open the gearbox and see if there is any problem.

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    Are you oiling the chain regularly? It may be that links are stiff in the chain causing it to feel tighter than it actually is. I'd start by wiggling each link in the chain a bit to see if they're moving freely. – MeltingDog May 12 '17 at 6:45
  • I do oil my chain regularly. I do that after a thousand kilometres. The chain seems to be little greasy. And it sticks to the sprocket making the sound. There is no chain cover. I ride around 60 kilometres per day. What can be a long term solution in this case. – tushar May 12 '17 at 7:20
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    When it tightens up, what do you do to loosen it? From the pictures I'm seeing, the sprocket side (at least) has a chain tensioner at the back of the swing arm. You may try marking this and the axle locations to see if what is moving. The only way I know of for there to get more tension in the chain is for these two areas to move and create the tension. It cannot get tighter on its own. If it did, you'd soon run out of adjustment room. – Pᴀᴜʟsᴛᴇʀ2 May 12 '17 at 11:42
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    Is your rear axle moving on it's own? Make sure it's tightened down to the proper torque. Chains stretch over time, making them longer and increasing the amount of slack. A chain that tightens on its own is very strange. – raydowe May 12 '17 at 14:50
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    I think one of not both of you tensioner nuts/rods have begin to or are already stripped. pull the nut off check it and the rod, if you see any wear then replace. then make sure you loosen the axle nuts before adjustment, and tighten them back up after adjustment. that's one way these things get stripped. – axa May 13 '17 at 9:16

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