Update, 2nd hand components got rid of the noise, but then leaked brake fluid continually!!
Have refunded parts.
Now am stuck with original parts and am re-fitting today - hopefully they won't leak also!??
>>>>> Believe prob may be the cannister/accumulater and that it is low on nitrogen!? Soarer's etc can get easily for $400-$500 BUT GS300 is of course only available from Japan and costs $700! Ouch!
>>>>> Will try and get original parts back in place, see how it goes, and then source accumulater!!
CRIKEY!!!!!!!!!!!!