HST Whine.....Gone.......!

philip53 · Dec 16, 2019

Like most folks, the HST whine on my Kubota was horrible. I have a 3301, and one of my neighbors has a BX with a FEL. We have both complained about the noise for some time. He recently filled his ROP bars with an expanding foam and got a six decibel reduction as measured where his head would be on the tractor. Now that is a lot! Being a bit skeptical, I still decided to try it on my 3301--and I was completely surprised. It worked better than I had ever expected. The whine is virtually gone. The theory is that the hydro unit transmits the sound directly into the ROPS bars and it resonates like a bell. Now I know this is hard to believe, but for only about $12 you can try it yourself. I would not use the foam in the can, as it would not be able to fill the bars completely. We both used a two part foam used to set fence posts (link below). It pours in as a liquid and goes all the way to the bottom to begin expanding. One package just does fill the entire ROPS bar system on a 3301. Mix about four ounces per lower leg, then adjust to fill the balance. Just be sure all vent holes are sealed! Don't forget to do the top bar as well, just fold it over to fill. It will expand out the tops of the bars, just let it dry and break it off.

https://www.lowes.com/pd/Sika-Polyurethane-Fence-Post-Mix-Actual-Net-Contents-33-fl-oz/999977070

One problem though, with the whine gone, the other engine noises seem to be even louder! Time to work on that now......

North Idaho Wolfman · Dec 16, 2019

philip53 said:
Recently filled his ROP bars with an expanding foam

While I applaud your efforts to reduce noise, you've now rendered your tractor unsellable to a dealer.
They will have to remove and replace the ROPS to make it sellable.

Just be prepared for that hit if you try to trade it in on another.

Also If any damage occurs to the unit or to a person an insurance company has the ability to deny any claim and you would be personally liable, this could also happen if you sell the tractor to another private party, and the damage or injury then occurred.

Brinet · Dec 16, 2019

Can you explain why the warranty would be compromised?

It doesn't sound like any holes were drilled or any structural modification was done.

philip53 · Dec 16, 2019

Please understand if I don't agree with your assessment. Totally effing ridiculous to assume that lightweight foam has ANY consequence to strength, stability, etc.

Real world, not frickin' lawyers. Will have zero affect on resell to anyone but idiots. Doesn't bother me a bit, unlike that damn whining noise.

Ok, ready for the pile on....

William1 · Dec 16, 2019

Yeah... I do not 'get' why filling the ROPS with foam is a problem.
Unless it rusted/corroded it, it should have zero effect on its' ability to protect. I can understand being leery of holes drilled as a force in just the right spot at a hole can induce collapsing. But the foam?

eserv · Dec 16, 2019

William1 said:
Yeah... I do not 'get' why filling the ROPS with foam is a problem.
Unless it rusted/corroded it, it should have zero effect on its' ability to protect. I can understand being leery of holes drilled as a force in just the right spot at a hole can induce collapsing. But the foam?

ANY modification to safety equipment not authorized by the manufacturer absolves them of responsibility and places the responsibility on the shoulders of the modifiers.

tiktock · Dec 16, 2019

eserv said:
ANY modification to safety equipment not authorized by the manufacturer absolves them of responsibility and places the responsibility on the shoulders of the modifiers.

By that logic, wouldnt strapping u-bolts with lights hanging off them potentially change the way stresses were imparted onto the ROPS if the tractor flipped onto those housings?

How could foam inside somehow compromise a ROPS but not all the many u-bolts and weight hanging off them that comes with every single light installation, drilling or not?

eserv · Dec 16, 2019

tiktock said:
By that logic, wouldnt strapping u-bolts with lights hanging off them potentially change the way stresses were imparted onto the ROPS if the tractor flipped onto those housings?

How could foam inside somehow compromise a ROPS but not all the many u-bolts and weight hanging off them that comes with every single light installation, drilling or not?

Why do you think we never installed anything to the rops on tractors we sold that wasn't supplied by Kubota? As a dealership it just wasn't worth the risk. I really don't like dealing with lawyers

atitus · Dec 16, 2019

I can't see how the foam would compromise the strength. But resale would have potential to be a problem. I ran wires up through on mine for some lights. Might annoy someone in that way.

I am intrigued by the results though. I may try putting something removable in there to see if I can replicate the effect before filling it. Maybe stuffing it with some old bedsheets?

North Idaho Wolfman · Dec 16, 2019

Well i guess you told me,

Sorry you think I'm just effing ridiculous, and an idiot... I just know facts not fallacies.
I try and be nice and just inform you of the consequences and you tell me off, why thanks!

Eserv said it perfectly!

One simple reason why it's "altering the structure", Foam traps moisture, moisture causes rust, rust weakens the structure, structure is now compromised.

Now to answer:
"Well it's just open and moisture can just get in there", " what's the difference?"
It's open so the moisture can get back out too!

Foaming your ROPS is a bad Idea, period!

Go take a trip to a local dealer and ask them...
Any good dealer will say any altered ROPS must be replaced before a sale therefore it reverts to you to pay for that replacement, usually in the form of a substantial lower trade in value!

ItBmine · Dec 16, 2019

And some dealers even drill holes in the rops to mount work lights. Mine included. LOL.

BigG · Dec 16, 2019

If the whine is so troublesome why not wrap the ROPS with a pool noodle, or pipe insulation and go from there. That might help and not cause any any problems with any modifications to the ROPS. And I would say that if you want to fill the ROPS go for it. You have been given a warning that it might cause you a problem. After all Wolfman has just a little experience with the tractor world and has never posted a thing to bring harm to anyone.

You learn a lot when you keep an open mind.

I forgot about the u-bolts, they can be removed without damaging the ROPS. Thus they are not a problem if the dealer wants them removed. It might be a little difficult removing all the foam.

tiktock · Dec 16, 2019

One other comment unrealted to ROPS modification is that this simply suggests the ROPs are taking a vibration audible. When removing "ring" from anvils, we commonly wrap their base in heavy chains. I would think a similar attempt on the ROPs would easily replicate that dampening effect without needing to be filled with foam but would take some experimenting.

For me the HST whine isnt a nuisance and went down considerably with my 50 hour maintenance but I'm also not on my tractor multiple hours a day, either!

BX23S-1 · Dec 16, 2019

Actually, mine dosent whine any louder than my wife does... so i`m use to it... i also do have selective hearing syndrome, happy thoughts while being on the tractor drowns out everything

Yooper · Dec 16, 2019

What is basically happening when you fill the ROPs with foam is you are changing the natural frequency of the structure. That being said I am sure there is an engineer on this site who may be able to explain ways to change frequency without compromising the structure.

cliffboyer · Dec 16, 2019

I would have no problem using the foam. But an alternative idea might be coating ROPS with a bed liner coating.

For me the whine is tolerable, plus I always use hearing protection. An upside to the whine is, in certain situations, it gives an audible indication of how tractor is performing with respect to range selection & speed. Which is almost always M or L range.

sheepfarmer · Dec 16, 2019

cliffboyer said:
I would have no problem using the foam. But an alternative idea might be coating ROPS with a bed liner coating.

I was thinking of a nice macrame tightly wound covering, maybe tastefully made with baling twine

St8 e · Dec 17, 2019

William1 said:
Yeah... I do not 'get' why filling the ROPS with foam is a problem.

Unless it rusted/corroded it, it should have zero effect on its' ability to protect. I can understand being leery of holes drilled as a force in just the right spot at a hole can induce collapsing. But the foam?

I have to remind you that there is a man that is a multi-millionaire because his coffee was too hot...

While I feel like this is a good idea, I have to agree that a dealership will replace it if traded in, etc...

Sent from my iPhone using Tapatalk Pro

japollner · Dec 17, 2019

That foam definitely traps moisture and will end up rotting the ROPS from the inside out. Eek!

KYRidgeback · Dec 17, 2019

Wonder if Plasti-Dip sprayed on would improve the harmonics. Easily removed also.

HST Whine.....Gone.......!

New member

Moderator

New member

New member

Well-known member

Well-known member

New member

Well-known member

Member

Moderator

Well-known member

Well-known member

New member

Active member

Well-known member

Active member

Well-known member

Member

Member

New member