70cc engine rattle

[Cordogs]

Hey lads, so I got this third quad started the other day and it has this terrible rattle noise coming from the head! I didn't get a video of it running before I pulled it out but it sounded just like this.

<iframe width="420" height="315" src="https://www.youtube.com/embed/jHm3xp5huHU" frameborder="0" allowfullscreen></iframe>

It was idling fine and has good compression, but the oil is a crazy silver flake fest!
So it's now on my bench with the head off and the bore is spotless, the piston and valves are pretty well untouched and the valve clearance was fine!

So I'm now stumped! Any suggestions???:confused-smiley-014

 

[my67xr]

140 pit bike or 110 quad ?

If it's that pitbike, could the noise be coming from the oil spinner ?
I reckon it might be loose/broken

It's not an 8mm socket rattling around in the exhaust is it ??

 

[Cordogs]

Jesus Christ mate I didn't even think about that! :lol:

It's a 70cc quad, but what's with the silver flakes in the oil?
Mind you its most likely the original oil too?

 

[Cordogs]

Nope definitely no 8mm socket in the exhaust! :grinning-smiley-003:

 

[my67xr]

Auto clutch ?
They do wear a bit, might pay to take the clutch cover off and check it out.
Take the 4 screw's of that hold the cover on the clutch, that is a filter too (centrifugal), like an oil spinner
There'll be a lot of grey thick gunk in there, wash it out and clean the filter screen in the bottom too.
Might spot something that's been grinding/rubbing if it's real bad

 

[headsmess]

cam chain roller snapped its bolt off? that idler that sits halfway down the cylinder often sounds like that.

someone tore it apart before and failed to re-install spring/plunger for the chain tensioner?

cam sprocket rubbing against cover plate? they should have a small prong thingy on the cover to stop it moving over too far.

probably wont make any difference...is the glitter magnetic or alloy?

could be gudgeon pin bearing on its way out...