Had this problem for a while and its hard to explain, basically its like a grinding noise in 6th gear between 30-40 mph when i pick up speed the noise fades out.
This doesn't affect the performence or the speed of the bike, but im thinking of selling up soon and i know this may put people off so any suggestions would be great.
Problem occured when i was changing gear box oil and i didn't put enough gear box oil in (ran out) and later that day had a phone call so i had to go out and the noise came on the way home. bought some more and topped it up. Been like this for about 2 months now.
thats a normal speed to be using the 6th gear i think.. I always use 6th gear when im driving. No reason to be at 8 rpm to drive in 35 mph when you could be at 4 k rpm ? (those are just random numbers but you get my point ? i have a dt re without rpm gauge xD )
could be bearings got hot and wore exsessivly due to lack of oil some where
then the slow speeds with less load with low centrifical forces the bearings are rumbling then when the speed increases the bearings spread out reducing the noise
we once pierced some crank cases on a cr 80 jumping it and landed on a boulder it dropped most of the oil and this did a similar thing
so id say a complete gbox /clutch strip and check every thing
with the rpm 2 stroke engines/boxes run at worst thing you can do is starve them of oil lol
only go that speed in traffic haha and i can't over take :P, norfe sounds about right, i striped my clutch about 2 weeks ago and the barrel was scratched outside and inside so i had a new one, must be something to do with the gearbox then, any tell tale sings to look for or? yehp starving with oil is a stupid thing to do haha
just look for play in bearings mate check all components look for wear marks and blueing steel normally goes blue when it gets hot and is easy to spot,but ull feel owt that will need changin really,if u get it opened up any way may aswell chuk a ful set of bearings in dont cost much...