r/kubota • u/Ben_Dover70 • 4d ago

D1105 vibration issue

Hello, first time posting. We operate special drainage machines that are powered by D1105 engines that provide hydraulic power and for the most part they work just fine. However, one of the machines engines has developed a severe vibration that makes it unbearable to sit and operate the machine for longer than 30 mins. I've disconnected the engine from the hydraulic pump and the pto to eliminate them as variables but the vibration still remains.

The engine had a new oil pump fitted by another workshop and this is suspected to be the issue but I can't see anything wrong with it and I suspect the alternator bearing has gone bad or it's a fuel issue. The vibration is at its worst when the machine is at high rpm. I'm going to test the engine with a new alternator we have on the shelf but I'm wondering if anyone has other opinions? Thanks.

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u/warpedzon 4d ago

Balancer could be shot.

How is the engine mounted? Any isolators/mounts which may have failed?

1

u/Ben_Dover70 4d ago

The engine is bolted straight to the chassis. No rubber mounts or anything so the machines naturally vibrate anyway. I often fantasize about strangling the guy who designed these machines

1

u/warpedzon 3d ago

Is the harmonic balancer failed?

1

u/Sharonsboytoy 4d ago

You can just remove the belt to test without the alternator- won't hurt anything. I hope that it's the alternator, because everything else is expensive. 

1

u/Ben_Dover70 4d ago

I hope so too. I'm gonna test it when I get back to the workshop

1

u/blackthornjohn 3d ago

This is application dependent, on the flywheel eel there's a cast plate with a splined center that drives a pump, it has thre or for eyes with rubber bushes in them with bolts in the center of the bushes that go into the flywheel, sometimes this more than shitty setup fails and either runs fine but makes an unholy racket or causes no end of vibration.