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· Registered
141 Posts
Discussion Starter · #1 ·
I am looking at a B7100 that I think I can buy fairly cheaply. The owner says he thinks it has some "blow-by". I was wondering how difficult it is to put rings and whatever else is needed to "freshen up" the engines in these small Kubotas. Also, how expensive are the parts? I've heard they aren't nearly as expensive as you'd think. Thanks.

· Retired MTF Admin
11,163 Posts
Hey Tiger,

IMO, it's knowing how far you want to go...or what you discover, that dictates the price of parts. Once you begin there is a punch list of items you should have and items you must have. But getting a parts list together is relative to the tear down.
I/E: Once the head is off - you might consider re-doing valves, seats and magnaflux the head. After removing the pistons and honing the cylinder walls, checking wall taper (using the new rings and measuring the gap) may want to replace the rod and main bearings.

And so it goes, does one settle for rings only or complete the head and bottom end too?

Parts are inexpensive compared to other (larger) tractor brands.

· Machinery enthusiast
4,256 Posts
Like most things it all depends upon your experience. These Kubota diesels are pretty straight forward and if you've done any kind of engine before you'll not have any troubles at all.
I did a forum earch on "engine rebuild" and came up with a few hits. This one had some good info.

This is a search for "rings" up in the Kubota Big Boys forum.

You can try searching both forums for "blow by" or "piston" , etc.

Good luck and let us know how it's going.

· Premium Member
5,557 Posts
My own experiences is once you have taken apart the engine that the rod and bearing generally need to be replaced. I just hate tearing into something thinking that I am going to replace one item. I go in to inspect and check everything

I recently tore into my Kubota because I thought that the oil pump was failing and discovered that the oil pump (I am still going to replace the oil pump anyway) was fine but the camshaft was bad, the bearings were toast and the rings were way out of tolerance. So I am doing a complete engine engine rebuild.

I am currently waiting for all the parts to reassemble the engine and get the head and the crankshaft back from the machine shop. I am one of those that goes in once and once out and if anything is marginal it is either rebuilt or replaced with a new part.

There is just no way you can tell on a engine rebuild until you take it apart, I also discovered the clutch was marginal so that was a added cost.

Since I am having a new garage built and the Kubota is sitting on the side lines and once the parts all arrive and some of the parts are on a slow boat from Japan as this is a gray market tractor. I will have to let the Kubota sit a bit longer until I have the free time to finish what I started last month.
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