Combines rotor slow

[M__Gorden]

The 80-88 series combines can have rotor speeds as high as 1100 rpm no load. Engine rpm, belt width, and limit switch settings play a role in how high of rotor rpm you can get. When the rotor rpm is set at the high end of its range, a new rotor drive belt should be about flush with the top of the driving sheave. If you are unable to get the driving sheave closed to the point that a unworn belt is at the top, the high limit switch may not be set properly. Of course the engine rpm needs to be set according to the manual as well. How much the rotor drops under load is effected by the belt tension setting.

 

[shellman]

Agree that limit switches can be a big issue, expecially if rotor belt was changed and switches not checked. You don't say what model machine you have, but have found that especially on 2100 series machines that engine rpm's have been as much as 150 rpm low. If that is the case you should also have a low power complaint. 0n all models machines make sure that the banded belt from the gearbox to the jackshaft is tensioned properly and the tensioning rod does not have a notch worn into it preventing movement. Seen this before also. For what it's worth.