Have had my B2650 with cab for two days and compared to the 21year old Ford 1215 I traded in this unit is really loud! Both have the HST transmission. Borrowed a decibel meter from a neighbor and at 2400 rpm standing still the engine puts out 67db but when the HST is engaged and riding in the pasture the sound goes up to 85db. I always wear hearing protection when using ANY machinery since I have been wearing hearing aids for years, but this level to me is way into permanent hearing damage range. Will the pump quiet down when broken in or is this normal for Kubota? My NH T4.75 which is 75 hp is not even this loud at WOT. Yes, the hydraulic fluid level in thr B2650 is at the correct level. Thanks....
In answer to the first part of your question, "Will the pump quiet down when broken in or is this normal for Kubota?"
Hate to say this, but unless something is wrong with the pump clearances, I doubt it will become any quieter as it is broken in. My guess is that it won't change much at all.
We know that hydraulic pumps are made very accurately with tight clearances. It would be rare for the internal clearances to be inaccurate, but possible of course. Anyway, in a normal hydraulic pump the whine is least when it is new and tends to increase with wear. In fact, when a pump begins to make a lot of whine it means something is not right - wrong fluid, wrong fluid level, or worn parts.
First things first though - and luckily any small change in pump whine pitch or amplitude can result in way less resonance within the cab. So it's worth looking at how the pump is mounted to see if you can improve the damping of the pump vibration before it begins to excite the cab. I've heard all kinds of stories about damping vibration out by using flex arms and weights bolted to the case to soak up vibration. Mechanically that makes sense, but I've never done it myself. I did improve one hydraulic pump by tightly wrapping the most active part of it's case with insulation and duct tape. Big improvement.
As to the second part of your question, "...is this (whine) normal for Kubota?"
I can't help much there as I'm comparing to other tractors rather than to other Kubotas. None of my tractors makes much of a hydraulic whine, but that may just be because I tend to run at low RPM. My own preference is to set the throttle for minimum noise instead of maximum power.
Here's one idea that may help, though. At the first service, you might want to try a different fluid. Our Kubota M59 came with New Holland -Ambra Multi G 134 hydraulic fluid from the dealer. After a few hundred hours I got curious enough to switch oil and filters over to try Kubota's new SUDT hydraulic fluid. Well, the SUDT definitely increased the whine. Maybe it was just our particular machine, but the HST whine changed from being barely noticible all the way to being hard to ignore. In fact, it increased it so much that within the month I kissed a few hundred dollars goodby and switched back to the NH fluid. That put things back to normal, so apparently no harm done.
That experiment kind of surprised me. My expectation was that different oils would sound more or less the same in the pump. Not so.
Also interesting is that on the NH website their Multi G 134 is rated as a general purpose trans/hydraulic fluid, rather than being one of their severe duty fluids. I have no idea what that really means, but the 134 worked for us. Might be worth a try with yours.
luck,
rScotty
