Picked up a cheap 999s today. Cheap because the seller had taken bike to workshop with a whining noise in the engine and was told the big end is on its way out ! I haven't been able to take it for a ride yet so can't determine too much. It sits at idle beautiful with no whining but when you give it some throttle it whines. I thought maybe it could just be belts but noise does seem to come from deeper down ! Has anyone come across this before ? Will the big end whine or could it be something else ? I thought/ hoped maybe the workshop could have it wrong ?? Any advise would be appreciated ! Cheers
First I'd check the belts are ok and the tensioners are correct. Rig up an oil pressure gauge and see how the pressure looks. Pop the little cover off the left side crankcase and see if the little crank support bearings still in one and there's no movement in the main bearings. And drop the oil and check the strainer filter. Hth
Usually Big end bearings don't whine when they're on their last legs, they tap or knock. A Whining sounds more like gearbox problems, do all gears select properly, and does it go into neutral easy at a standstill?
Interesting... You can check the main bearings through the cover then - perhaps you could be a little more specific about exactly how??
It's not the most scientific method. But as the mains degrade you will begin to see axial movement in the crank pins. Which in no time destroys the generator support bearing. Remove the cover. Use a soft lever between the casing and the crank pin to gently attempt lift the crank. Either look or feel for movement. When mine waved the white flag. I found most of the balls stuck to the generator magnet.
