Picked up an 81 XS650 Special with 11k. Working on a budget restoration but have noticed a noise on hard braking, sounds like a seizing needle bearing. I've heard similar before in an RD350 that had low trans fluid from leaking CS seal. Or maybe cam bearings? Other? Fresh 15w45 Rotella oil non synthetic. Level is in the lower third of the sight glass on the center stand, didn't want to overfill per info I learned here, extra leaks etc. Engine is untouched & 40 yrs old. Tomorrow I'm gonna try putting more oil in it just to see if it changes but it shouldn't be happening at the current level imo. It seems likely braking is sending oil forward away from said bearing but because it only happens during braking, I havnt been able to isolate the exact source. At first I thought it maybe an odd interaction with front rotor/pads but rear braking produces the same... Ideas? Bike runs well with good power, fully rebuilt carbs(bs34's), adjusted the valves, timing chain, drive chain and clutch. Changed right case oil filter but didn't do the sump yet(?). No other significant mechanical noise, no modifications other than needles shimmed ever so slightly richer. Thanks for any and all experience or suggestions.
Steve
Steve