DT125 engine rattle <help plz>

[darkangel]

Got a strange noise that seems to be getting louder, sounds like its comming from the middle of the barrel, i think its a rattle and it stays with the revs.

Did a top end rebuild a few weeks back, ran it for 40 miles with no odd sounds then had a coolant failure (caught it before the temp gauge hit the red line) and the engine got flooded with coolant.

Took the head off and checked that everything was on correctly, gave it a clean, took the right side engine casing off to fix a faulty gasket (trany oil side, but it had plenty of oil left), bike started but it was making a rattling noise at idle and at specific revs.

A week ago i got annoyed with the noise so i stripped the head and the barrel, gave everything a clean and all looked fine, put it back together but now i have the noise in all the revs instead of just at idle and a few specific rpm's.

I thought that maybe i did something wrong when i removed the engine casing but the noise doesn't originate from around there, i thought it could be the big end but there is minimal side play and zero vertical play, it sounds like it is comming from the top end and if i was to describe the sound it would be like... a loose bolt or something rattling inside the engine

My bike has got 11k miles on it, if there was something sinister that required splitting the engine would it be cheaper to try get a bargain off ebay?

[Willenium]

When you did your top end rebuild, did you replace the small end bearing as well? Over time they become loose and rattle so it's worth replacing them while you've got the engine apart.

[darkangel]

yeah i got a new piston, rings, gaskets and bearings

[david1959]

when you did the re-build did you re-use or replace the gudgeon pin circlips.... old ones re-used might have come loose or broken

david
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xs500c owner from 1978