Rattle / bottom end rumble

[Hugh Jarse]

EC300 - 07.

Hi all,

I've had my main bearings replaced less than 30hrs ago and the rumble noise came back recently... After riding it on some green lanes I'm almost certain they've gone again. Really annoying bottom end sound at low RPM, huge vibrations through the pegs (to the point of pins and needles when foot placed on them).

Does anyone know why this could have happened so soon after having them done / what else could give these symptoms?

Top end is in great condition.

It's not chain slap.

Not header pipe rattle.

Power valve is fine.

Definitely bottom end. Definitely rumbling rattle noise.

Doesn't appear to have dampened the power.

Oil same as I've been using for years. And running 40:1 on 2 stroke.

Only used for green laning and enduro but not using the 300cc to anywhere near it's potential.

Cheers in advance.