Sickle bars always noisy when off the ground?????

[kentuckydiesel]

I've got a JD model 39 sickle bar mower that I picked up used and needing a few things. It's a 3pt mount. If I have it running and raise the bar off the ground it gets really noisy and I fear I will break the pitman. Is this normal? Do I have to worry about the pitman breaking under these conditions? I think the noise is from the bar flexing downward while in the air and may be binding slightly. Thanks, Phillip

 

[beenthere]

I recall there is a lot more "chatter" when the bar is raised, but slowing the rpm down will calm that noise down. I don't think there is a danger of ruining or breaking the pitman arm, if it is greased properly and in good repair. Certainly more load on the arm when cutting than when running free. But i can understand your cause for concern.
I'd just lower the rpm a bit.

 

[sweettractors]

<font color="blue"> </font> I think the noise is from the bar flexing downward while in the air and may be binding slightly. <font color="blue"> </font>

There is a adjustment on those mowers to cause the tip of the bar to come up quicker when the 3 point is raised. You may want to set the upper limit on the 3 point lift control lever on the tractor (the pto may be getting in a bind on the extreme up position)--Ken Sweet

Sweet Farm Equipment LLC *2 Stores in Central Ky to Serve Our Customers Needs*

 

[scout180]

I agree the noise likely comes from the bar flex putting pressure on the throat plates/guards. However, make sure the pitman is the spec item - improper length could affect timing/position of cutter sections in relation to complete stroke through the guards....a long shot, but worth checking. I don't remember if the manuals show the measurement or not.
It's been 40 years since I ran the sickle bar mower on my Farmall M!

Dave in VA
Raised on an IN farm