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Noisy 4Rt Top End Noise

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Hi guys,

Once again i have problems with my 4rt 280cc repsol machine.

She started making a tapping noise a few outings ago, didnt sound too serious but its getting worse, and I now want to get to the bottom of it. I'm debating wether to take the engine completely out or leave it in.

The noise it makes sounds like a small loose piece of metal hitting another, it "taps" aprox 3 times per second.

Anyone had a similar problem?

Many thanks in advance for helpful replies.

Peter

Hi Peter,

Where is the noise comming from, top end or bottom end? If its top end, could well be the tappets, when was the last time you checked them?

  • Author

It sounds like top to middle end, I had a mechanic friend of mine listen and he said piston, but it sounds too slow to be the piston.

I checked the valve clearances a few weeks ago and were fine, didnt make any difference to the noise at all.

Could it be cam chain?

Peter

I am wondering on the off chance that you may have recently changed oil brands or viscosity.Good luck chasing down this noise.

Nope, havent changed oil brand. ELF HTX as always

ELF HTX 740 is transmission oil! However, I presume you are not using that in the motor but a high quality 10W40?

I would have thought valve clearances going by the description. Would be worthwhile changing the cam chain but that would give a rattling sound.

Big John

Hi,

Having heard a recording of the the noise your bike is making, the tick is dependent on engine speed but the "tick" is only every third or fourth firing stroke not every revolution. It sounds like something up with a link on the cam chain and makes the noise when the bad link meets the cam sprocket.

Enjoying the return to the sun?

  • Author

Sorry I got mixed up there with my oils. I had a look and the engine oil is indeed another make.

Yes the noise seems to be on every other stroke, at least not every one so I will strip what's need to get a look at it better. Anyone know where to get some flywheel pullers? Cheap as can be?

Sun is behind clouds now, was better over there!

You took the sun back with you it raining again. Did you enjoy being a tourist? Better with the Beta you did ok

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