????

[Honda Ex Rider]

I am rebuilding my 400 and i was wondering if i would be able to sandblast the fins on the head or would it just ruin it i wanna get them cleaned up,i used like every cleaner out there but no go???

[250X_project]

regular WD-40 and a wire brush worked good on mine, mind you no cleaner will make it look perfect again, I couldn't tell you about the sandblasting, all I could do is advise you to take it easy on it.
Also I'd suguest you remove the valves and clean up the cumbustion chamber with a wire brush drill attachment, then grind valve seats ( probably not nessisary for a quad as new as your) then lap valves and test for leaks. Using new or re-faced valves would be your best bet. ...also replace valve seals...EBAY for best deals...good luck