Vibration in MX-5

Michael_Porter · Mar 21, 2006

I hooked up my brand new MX-5 to my JD 3720 the other day. It ran smoothly at lower RPM, but when I advanced the throttle to the 540 RPM speed, I noticed what seemed to me a lot of vibration. I had a 7' Woods cutter on a previous tractor and it didn't vibrate this much.

Any advice from other MX-5 owners? How much vibration is normal? Can something be done to better balance the blades? Should I take it back to the dealer?

rockyridgefarm · Mar 21, 2006

raise it up and look underneath to start out. I always turn the tractor off before getting back there. Make sure the blades are swinging freely and it isn't something silly like shipping wire... If that is OK, check the gearbox for gear oil. Then its time to talk to dealer.

My MX is really smooth.

LeadPoison · Mar 21, 2006

I would give your dealer a call. Sounds to me there is a balancing problem.

Dutch445 · Mar 21, 2006

Yea,,
might want to make sure that both blades are
spun outwards,, and not locked together or
something goofy underneath. I would have
imagined the dealer would have run the cutter,
and caught any big problems. Sometimes when
the cutter stops,, they stop pretty abruptly, and the blades hit each other , can the wedge like this?
worth looking under like others say and see what's happening,

also, take a look at the pto shaft and see if you are getting any wobble there... it that's bent,, you can get vibration also.

let us know what you find
/forums/images/graemlins/cool.gif

rockyridgefarm · Mar 21, 2006

Notice Dutch didn't mention doing this with the machine OFF. That's cause he is real TOUGH. I guess I am just a whimp.

MARTIN65 · Mar 21, 2006

I have a 513 I run behind a 4210. Sometimes if have to start the cutter 3-4 times before it runs smooth. I bought it new with the tractor, the dealership sent a mechanic out to look at it, but he didn't find anything wrong. After the restarts it will finally run as smooth as silk.

browns40 · Mar 21, 2006

Hi Michael,

I have noticed a vibration is present all the time on my tractor when running the MX-5 at 540 PTO speed... when something solid gets hit & blades swing erratically it's MUCH more noticeable...

Shut it down if the vibration worsens & then restart once the blades have completely stopped spinning.

It's the only attachment I have that suggest running the PTO full tilt, so I wonder if that in itself is some of the vibration...

I do not run it at 2600 RPM's though, usually I'll pull back to 1900-2200 on consistent material, and only crank it up for saplings & particularly heavy stuff... it saves fuel, wear & tear, & most importantly the ear drums! /forums/images/graemlins/wink.gif

Go back to your dealer & ask to test drive your same set up to feel it there... if it's the same...

Happy tractoring! /forums/images/graemlins/cool.gif

jeffinsgf · Mar 21, 2006

</font><font color="blue" class="small">( ...I do not run it at 2600 RPM's though, usually I'll pull back to 1900-2200 on consistent material, and only crank it up for saplings & particularly heavy stuff... it saves fuel, wear & tear, & most importantly the ear drums! /forums/images/graemlins/wink.gif...)</font>

Do yourself, your eardrums, your tractor and your cutter a favor. Buy some earplugs and kick that throttle up where it belongs.

AKfish · Mar 22, 2006

Doesn't seem reasonable that a new mower should be jouncin' around! As others have mentioned -- look for a wooble in the PTO shaft or the blades (could have a bent one) or the gearbox shaft is out of kilter. After a good eyeballin' -- I'd be on the phone with my dealer -- even if something wasn't readily apparent. Could fail later on and the dealer wouldn't know the history of the issue.
Don't intend to highjack this discussion and my apologies if this is too far off the track but this thread brings up a question that I've had on several occasions... (besides excessive vibrations when running something off the PTO). What is the recomended engine RPM when you're working a 540 rpm attachment? Should you always run at ~2600 rpm? Even in light stuff? And if you're not running the engine rpm's at the rated 540 PTO -- then I'm assuming that the PTO speed is less than 540? Correct? Thanks. AKfish

jeffinsgf · Mar 22, 2006

I don't think it is 2600 on every tractor. It depends on the gearing, but every one I have seen has an indication of what engine RPM yields 540 RPM at the PTO shaft. If you throttle back, your implement slows down. If you throttle up, your implement is running too fast. My understanding is that you should always run the implement at 540 RPM and adjust your ground speed through gearing.