Good afternoon I have a Kobelco machine that been down for awhile. Bucket and stick functioning slow, when the stick gets in half way it hangs up like it stops getting pressure, then slowly comes in. Had a guy come and check it out he swapped a valve not sure which one he swapped but whichever one it is completely slowed the entire machine down.
Sounds like you may have a damaged stick cylinder piston. It may have scattered debris in your control valve. uffex is the person to talk to on here about Kobelco problems.
Lift the tracks on the ground one at a time and check your track speed. Mark a spot on the track with paint, time 3 revolutions of the track. Check the other side see if they are close
Please take a look at your PM
Good day I suspect that the straight travel valve is affecting the fl;ow to the bucket & arm in addition to to the tracks. I suggest you approach the issue in the following manner, disconnect and plug the pilot lines to the valve and test the machine. If this does not result in a fix, I would checkout the actual spool, while the spool is electronically operated with a solenoid valve this need to be clarified before we look at other possible causes. Please see attached. Kind regards Uffex