New RTV1100 Owner

You might investigate if any machine shop near you can "knerl" the piston skirt on the suspected cylinder. It is a process to imress a pattern (a crosshatch usually) on the skirt and have material upset around the pattern and further fill the space between the piston and cylinder wall. It can quieten some engines.
Bryce

shinnery said:

You might investigate if any machine shop near you can "knerl" the piston skirt on the suspected cylinder. It is a process to imress a pattern (a crosshatch usually) on the skirt and have material upset around the pattern and further fill the space between the piston and cylinder wall. It can quieten some engines.
Bryce

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I suspect that would require the engine to be removed and stripped down? If engine removal is necessary then I would definitely opt to either replace the entire engine with a good used or rebuilt unit. The engine removal process on these things is pretty involved since it requires pulling out the entire transmission assembly. I feel like if I'm going to get invested in a task like that I'll want to take the easy (and more expensive) road so I don't have to do it again!

Despite the engine tapping that seems to come and go whenever it pleases, I have been using the machine for light duty work around my property. I don't really have any good stretches of land/road where I can open this thing up to evaluate the health of the transmission. The road that my house sits on has a couple of speed bumps that hinder my ability to go wide open throttle. I also have a few retired neighbors on that road who enjoy keeping a close watch on the road and reporting suspicious activity. I have made a few wide open throttle runs and it seems like the vehicle gets up to about 20mph fairly easily but doesn't seem to want to go beyond that. It also seems like it brakes a little too violently when I let off the throttle, but that could also be because I'm simply not used to the machine and its throttle sensitivity. My Uncle has a similar unit (can't remember if it's a 900 or 1100) so I'm going to try and get to his place this weekend and test drive his to see how it compares to mine.

All the work would be done on the piston skirt itself. I was understanding you had removed the pistons with the engine in place. It was just an idea I thought you might want to explore, I do not know for sure it would help your problem. At very least it would cost a headgasket. If you could find a machine shop to do it. I rebuilt an engine 60 years ago and reused the old pistons by knerling them.
Bryce

my 1100 used to put me through the windshield when i let off of the peddle. i bought a coast valve and now it is sweet.

shinnery said:

All the work would be done on the piston skirt itself. I was understanding you had removed the pistons with the engine in place. It was just an idea I thought you might want to explore, I do not know for sure it would help your problem. At very least it would cost a headgasket. If you could find a machine shop to do it. I rebuilt an engine 60 years ago and reused the old pistons by knerling them.
Bryce

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Sorry - I misunderstood your suggestion. After reading it a second time it makes a lot more sense. Knurling the piston skirt could absolutely solve my issue and I'll definitely keep that in mind as an option if the tapping issue gets worse.

aurthuritis said:

my 1100 used to put me through the windshield when i let off of the peddle. i bought a coast valve and now it is sweet.

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I visited my Uncle over the Easter weekend and he let me take his 2008 RTV1100 out for a spin. He only has 675 hours on his as he only uses it during the fall/winter for deer hunting. He is also very meticulous about the maintenance and he gets all of his work done at the local Kubota dealer so I'm fairly confident it's running as it should. After my test drives around his farm in high-gear I feel much better about my own RTV. I thought that I may have a bad transmission unit since it takes a while for it to build up pressure and then take off in high-gear, but my Uncle's did the same thing so I'm feeling a little better.

I'm going to take a look at all of the various components on the transmission that can be adjusted and make sure everything is within spec. I know that the relief valve on the back of the machine needs to be tinkered with as I sometimes have a tough time shifting out of gear, but if I press hard on the brake pedal, I'm able to easily switch gears. From what I have read in the service manual, there is a physical cable between the brake pedal and the relief valve that I am able to adjust. I looked at it briefly the other day and there still seems to be plenty of adjustment left in the cable and I also want to remove the linkages to clean them up and for a smoother operation.

Once I get the transmission to a point where I'm happy with it's performance and function I'm going to start cutting out the old rotted floor pans and weld in new steel. After riding in my Uncle's RTV with intact floor pans and a stock floor mat I was amazed how quiet the cabin can be....

On a side note, my Dad asked me to take his 1991 Kubota F2000 mower and figure out why the PTO won't go into high. His local dealer said it would be a lot of labor to fix the issue and he's better off scrapping it and buying a new one. I brought the old F2000 back home with me this weekend and will be tearing into that when I get time. I'm hoping it will be an easy fix. My Dad used this thing for almost 10 years with no issues and he really misses the 72" wide cutting deck. The machine runs great and only has 2400 hours on it (thinking the gauge may have died) so it'd be a shame to just scrap it. We just rebuilt the mower deck a couple years ago so that still has a lot of life left in it.

they are sometimes difficult to shift and that is normal. you can jack the rear tires off the ground and adjust the creep on the wheels and that sometimes helps. you don't need to adjust a relief valve. there is a cable that connects to a rear brake caliper that actuates a poppet valve that relieves residual pressure allowing faster shifts. my 1100 has a knob like a choke cable on the dash that also pops the poppet.

Lost my job three weeks ago so I have been getting a lot of lingering home issues taken care of. I had an old shed on the corner of the property where the termites destroyed the front wall....so I ripped it off. Now I can fit the RTV inside!

Also tore into the F2000 mower a bit and figured out the issue why it won't go into high gear on the PTO - worn splines on the high gear. Parts are on order and I'll be putting that back together in the coming weeks.

GOOD ON YA! Sometimes the hardest part of a job like that is simply "getting started". Once the task is undertaken it usually goes better for me after that.

That is a great space for your RTV . That's whats referred to as making a silk purse out of a sow's ear. collie

Wow - I didn't realize how long it has been since I posted an update on here - sorry about that. I started a new job in June of last year and I am traveling A LOT more than I was at my old position. I don't mind the travel all that much as the places I go to I have never been to before so it is interesting to me. I'm sure after more years of travel going to the same places the novelty will wear off.

The biggest downside of the increased travel is that I haven't been able to really touch any of my projects, including the Kubota. I did hit a major milestone with it today, though. After six years of on and off tinkering with another project (a Mazda pickup) I finally decided to call it quits and sold the truck today to a gentleman with fresh ambition and motivation to take it over. This has opened up a spot in my shop to bring the Kubota in. No more working outside in the elements!

I pulled the RTV in this afternoon and wanted to drain the oil to see how my bottom end rebuild is holding up. I have put about 50 hours on the rebuild and I am still hearing a knock in the engine. It's more noticeable when the engine is cold and idling and it does tend to go away once the engine is warm. It doesn't sound like bearing knock to me and I suspect it's piston slap. When I honed the #3 cylinder to get rid of the scoring marks in the wall, I think I took a little bit too much material out. According to the service manual, the bore I.D. was within tolerance, but it was on the high side. I didn't use an oversized piston or rings and you could visibly see that the #3 piston fit looser than the other two.

While draining the oil I could see what looked to be silver metallic flakes, but they are extremely fine. If I can manage to get a sample of the metal, I'll be able to tell if it's aluminum or iron, which will also tell me where it's coming from. Either way, I don't intend on doing another engine rebuild or replacing the engine any time soon so I'll just run it until it dies. I know piston slap isn't a good thing to have and will eventually do damage in the long term, but the question is how long is long? If I get 1,000 more hours out of this engine, I'll be happy.

welcome back. i have seen piston slap go for ever but on big heavy slow turning engines. these little kubotas run 3600 rpm but i suspect it will surprise us just how long it goes.

It sounds like a great change of pace with your job.- but keeping you busy .
I'll be interested in hearing what you have going on with your engine. Knocks I seldom want (unless its publishers clearinghouse at the door) If it were me, I'd change the oil often and use a quality filter . and see what it looks like down the road. Best of luck to you, your RTV and also your new job. bordercollie

Terrawombat said:

While draining the oil I could see what looked to be silver metallic flakes, but they are extremely fine. If I can manage to get a sample of the metal, I'll be able to tell if it's aluminum or iron, which will also tell me where it's coming from.

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If you still have your oil with the flakes or the flakes themselves, take a magnet to it. Aluminum isn't magnetic so it might help point you in the right direction.

bczoom said:

If you still have your oil with the flakes or the flakes themselves, take a magnet to it. Aluminum isn't magnetic so it might help point you in the right direction.

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This is what I did last night after emptying the oil pan. There were small bits of metal left over and I waved my strongest magnet over the whole pan. Some of the metal flakes stuck, some did not, so I have a combination of ferrous and non-ferrous material. Just based on the color of the non-ferrous metals I'm guessing it's aluminum, which is likely coming from the piston. The little bits that did stick to the magnet are probably the cast iron cylinder wall. There's really only one good way to find out and that's to tear the engine down again, which I don't think is worth the time and money at this point.

I'm just going to keep running it until she quits. I'll change the oil and filter more often than normal to hopefully get more life out of it, but I believe this engine's fate has been sealed. I'm not the least bit upset by it since I chose to take the cheapest possible path to get the engine fixed. I've found when you do that you usually wind up on the losing side more often.

Sounds like a plan. I'm thinking synthetic oil would help in this situation. Less friction.