LX5 Vibration?

[orlo]

Hi:

I have an LX5 that I've probably used less than 15 hours in 2 seasons. It's first 'real' use last season was maybe 4 hours hogging snowmobile trails. It does seem to work well but my question is do rotary cutters normally vibrate? Sometimes it's very smooth, but sometimes it shakes a lot. It's not the driveshaft either. Sometimes it vibrates enough to feel it in the 3720.

I lifted and blocked it yesterday (Before using it). Aside from a few nicks in the blades I didn't see any significant bending, etc. I did notice that one of the blades was 'stuck' in but I can't imagine it stays like this. While I was under there I sprayed some lube gel at the pivot points. There was some grass in the blade pivot point so the blades were very 'tight'. Gearbox is lubricated and ok, etc.

Any tips for minimizing vibration?

 

[jbrumberg]

orlo:

Clear all the debris away from the blades and blade pan/stump jumper and lube the blades so that they are free swinging. The blade nicks may be "ok" but if the nicks are really gouges then your whole system my be "unbalanced" with the resultant RC vibration. Jay

 

[RoyJackson]

Sometimes it's very smooth, but sometimes it shakes a lot. It's not the driveshaft either. Sometimes it vibrates enough to feel it in the 3720.

Any tips for minimizing vibration?

My cutter (60" Land Pride does the same. I think those pivoting blades get out of balance (one may be partially pivoted back while the other is straight) now and then. The area I cut isn't real flat so I may be digging into dirt occasionally.
The vibration doesn't last more then 10 seconds. If it doesn't smooth out after 10 seconds, I'll disengage the PTO and take a look when the cutter spins down (don't put any part of your body under the cutter if you do this!).
So far, I've found nothing awry...

 

[davkir]

I had a similar problem with an LX4. There is a discussion about this (2305 / LX4 problem)
It may also apply to the LX5.

 

[sunnyside360]

I have 3 rotary cutters - 5' Bush Hog, 6' Woods BB, and 8' Bush Hog - all of them exhibit the behavior you mentioned. The 8 footer is double spindle (very heavy) and can be the worst but can also be the smoothest of the three. So, I think temporary vibration is normal after hitting obstruction such as ant hill, heavy brush, etc. Like mentioned above, stop the cutter and look for wire, wood chip, etc wedged between the blade and pivot arm if it doesn't smooth out within 10 to 20 seconds. Sometimes just increasing engine RPM's helps to right the blades quickly.

 

[Flywheel]

Sometimes just increasing engine RPM's helps to right the blades quickly.

yep - or sometimes I just put the clutch in and let the RC slow down a bit and then pop the clutch back out (in neutral...) and this will straighten out the blades - doesn't happen often and i think it will happen less and less as it gets used - unless the stumpumper is bent...

 

[orlo]

Thanks. I'll try all those suggestions. It does seem to smooth out sometimes so I think it is a temporary condition. I will 'loosen' up the blades a bit though and clean out all the grass underneath.

 

[RalphVa]

My LX4 is sometimes very smooth and other times is a big rough. A couple times early in its life, the blades got crossed and wouldn't separate without some crowbar work, etc. The vibration in that case was TOO MUCH. Immediately shut it back down.

Other times, I think one of the blades doesn't swing out freely and thus causes some vibration.

I'd think the best thing to lubricate the swing points would be silicone, Super Lube. Grass and twigs get in there and keep them from swinging completely out. Think that's what causes the vibration. It'll only take one not coming out completely to throw it off.

Ralph