1995 Yamaha buzzer sounds when at full throddle

[Streamln1]

Changed:

Impeller, thermostat, poppet valve, acid bathed after cylinder cover removed, fuel/oil mixed together, took thermostat and poppet valve out tried that.

Does anyone else have any ideas?

[jb123]

what model/size ??????
oil system removed ?
new issue ?

[ausnoelm]

first off, put all the parts back in that are supposed to be there, running an engine without poppet vlaves and so on is NOT the way to fix something, the first thing you need to determine is if it really does over heat and is not a false alarm! so lets assume it is getting hot, seeing as it only does it at high RPM, you probably have a partial blockage in the cooling passages somewhere, Yamahas have quite small passages and do get blocked a bit, so it is time to remove any covers that will allow access to the cooling system.

[Tucker]

I'm following a post on another forum where a guy has crumbled zinks clogging water passages.