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Discussion Starter · #1 · (Edited)
Hi guys. Sorry for the long post, but wanted to try to be thorough.
Not my first time working on ATV/motorcycle engines, but first time working on a Rubicon/Utility type engine.
I have been around Rubicons, so I know how they are supposed to run/drive normally...just not that familiar with all the specifics of how they work.

I picked up a 2001 Rubicon 4x4 awhile back with an apparent hondamatic problems (acted like it was stuck in two gears at once in auto mode, would only move/drive in 3rd and 4th in ESP. It had over 1400 hours and 8500 miles on it. I basically drove it onto the trailer, drove it off the trailer and into the shop. Couldn't get much of a feel for how it ran overall or any other possible issues...because of the tranny issue and plus it wouldn't rev much above idle (dirty carb).
One of the first things I did was download a copy of the Honda service manual.

I totally tore down the engine, and started taking the hondamatic apart in an attempt to fix it if it was bad. It was obviously bad and beyond repair IMO (pistons were stuck, some were damaged, swash plate was grooved, etc.).
I picked up a supposedly good used hondamatic off ebay out of a 2014 with around 600 miles on it. I put it in along with replacing every oring and seal in the engine with OEM Honda ones, new upgraded Honda oil pump, new Honda oil pump sprocket, new Honda oil pump chain, new Honda cam chain, new Honda valve seals, new Honda piston rings, lightly honed the cylinder (since it was within spec, surprisingly), new gaskets, new angle sensor, cleaned carb, new UNI air filter. I thoroughly cleaned every nook and cranny of the engine, oil tank, oil cooler with brake cleaner and blew all passages out with compressed air. I torqued every bolt I put in, when reassembling the engine. I added Rotella T6 5w-40 synthetic oil to it. Valves set to spec.


First issue...
After I got it put back together, I took it for a test drive and it acted like the clutch was slipping (stock tires, BTW). It does shift through all the gears in high, low and ESP. But in the higher gears in low and ESP, and pretty much every gear in the high, when I give it much above moderate throttle, it doesn't accelerate as much as it should and if I rev it fast I can hear a squalling noise from the front side of the engine it seems. In ESP gears it doesn't appear to slip as bad, but it still slips...it won't spin the tires in the grass going uphill (front driveshaft not currently installed). It will climb a pretty steep incline in low or ESP mode in 1st, but I can tell something isn't right (I have to give it way too much throttle for no faster that it goes and there is no "snap" in acceleration when I stab the throttle (and no wheel spin). In reverse, there is no noticeable slip and easily spins the tires when backing up an incline on concrete (could just be the lower gear ratio, I suppose?).
No codes flashing or stored. I did the angle sensor initialization after install. I adjusted the TPS to spec when I put the carb back in.

Is the centrifugal clutch likely slipping and making the squalling noise, or is it possibly a hondamatic issue, or both?
The fibers on the clutch weights were very dark brown color, but I've heard you can't necessarily go by color to tell whether or not they are good or not. The clutch drum had no grooving at all in it and I don't recall seeing discoloration like it had gotten hot from the clutch slipping before.
The hondamatic shifts through all the gears and I don't hear any abnormal noises from the engine...no clicking, chattering, etc (other than the squalling noise, which I am guessing is coming from the centrifugal clutch slipping).
So at this point I am thinking (hoping) it is just a centrifugal clutch issue, but I am no expert, so I need some opinions/advice from people more knowledgeable than I am about this stuff. Does it sound like it is likely just a centrifugal clutch issue? If so, would you recommend just replacing the clutch weights? Or weights and clutch drum both? Or just rough up the inside of the drum with emory cloth to remove any potential glazing and put new clutch weights in?


Second issue...
I also thought I'd check the oil pressure, before I tore into the engine again, just to make sure it isn't low oil pressure causing issues. Well, it isn't a low oil pressure issue. At idle the pressure is 60-70 on the gauge and a little push of the throttle will max out the 140psi gauge. I tested the gauge with my air compressor and it appears to read accurately. These readings were on a "cold" engine...ambient temp in the high 80s. I didn't see in the Honda manual where it said you should check it with the engine cold or warm/hot.

Is that high of oil pressure normal on a rebuild with a new oil pump? I have the Honda manual and it says high oil pressure can be caused by...
1) Oil pressure relief valve stuck closed (I assume they are talking about the oil pump relief valve? Is it likely to be stuck closed, being a brand new oil pump and the engine internals being spotless on assembly?).
2) Clogged oil galley. (Not likely, as I cleaned every nook and cranny of the engine and blew through all passages).
3) Incorrect oil being used. (The Rotella T6 I am using is the same as I have read many, many other people use in their Rubicons, so I don't think that is the issue).

Any other advice or opinions would be appreciated and taken into consideration as well.
 

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Discussion Starter · #2 · (Edited)
Over 100 views and no one has any comments or suggestions?:sad

Here are some updates...
I don't think there is an issue with the oil pressure being that high, from what I have read elsewhere.
I replaced the outer clutch, clutch weights and springs. It is still acting like the clutch is slipping. There is not a squalling noise like there was with the old clutch parts, but it still makes a "not right" sound (kinda of like a whirring sound) and the revs go up but the Rubi doesn't accelerate.
I did not reuse the oil that I drained out, when I took the front cover off to replace the clutch components. I put fresh Rotella T6 in it.
I verified I am not losing oil pressure when the I get the "clutch slipping" feeling. So I don't think it is a hondamatic issue, from what I was told by someone much more familiar with hondamatics than I am.
I verified all the oil check valve pieces were in place and installed correctly. I even replaced the check valve spring...no difference in performance.
I talked to the guy I bought the used hondamatic off of and he says he personally tested the hondamatic before they tore the engine down. He said it operated normally. Of course this is just what he says, I have no way of verifying anything, but I don't get the feeling he is lying.

Does anyone have any ideas or suggestions on where I go from here?
 

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Discussion Starter · #4 ·
In your 1st post you mentioned that the front driveshaft is not on the bike.
Yes, I did. How would that cause issues? Would that not be any different than putting a 424 disconnect on and running in 2wd? My point with saying the front driveshaft is not installed is that it should easily be able to spin the rear tires in grass going uphill...but it won't.
 

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Well I thot I had nuttin to add; you had a great description and all too. I just don’t know anything about Hondamatic.

So perhaps two obvious things but all I gots:
is the Rotella your using rated for auto or motorcycle engine? Slippery auto oil could ruin the clutch plates.

Insanely high oil pressure? Do you have the right dipstick? My 02 Rancher has an oil filler on one side of the engine and dipstick on the other. It might be overfilled?
 

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Discussion Starter · #6 ·
Well I thot I had nuttin to add; you had a great description and all too. I just don’t know anything about Hondamatic.

So perhaps two obvious things but all I gots:
is the Rotella your using rated for auto or motorcycle engine? Slippery auto oil could ruin the clutch plates.

Insanely high oil pressure? Do you have the right dipstick? My 02 Rancher has an oil filler on one side of the engine and dipstick on the other. It might be overfilled?
The Rotella is JASO MA rated (which means you can use it in wet clutch applications). This is the same full synthetic Rotella oil that I hear many, many people use in atvs and motorcycles with wet clutches without any issues at all.

After more research, I found the oil pressures I am seeing are normal for a Rubicon with the new style oil pump. So what I thought initially was way too high of oil pressure is totally acceptable.
Yes, the dipstick is the correct one and the oil level is right on the full mark. Checking the oil level on a Rubicon is different from what I am used to. To check it, you start it and let it idle for a few minutes, then shut it off and let it sit for a couple minutes, then check the oil level.
Thanks for the reply.
 

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I don't have anything to add either. I've never worked on a Hondamatic bike and won't, because no parts or service info is available from Honda. All I know is the motor-side swash angle bearing is garbage (made with plastic separator) and there is a plastic pressure valve inside them that breaks and blows open. Hope you can figure it out.
 

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All I know is the motor-side swash angle bearing is garbage (made with plastic separator)
That is true for the 2001 to 2004 (1st gen) Rubicon Hondamatic units, and probably what took out his original. But not true for the 2005 to 2014 (2nd gen) Rubicon Hondamatics. No plastic carrier in those bearings. @skyhiranger were you able to verify the used unit you bought is good?
 

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Discussion Starter · #9 ·
I don't have anything to add either. I've never worked on a Hondamatic bike and won't, because no parts or service info is available from Honda. All I know is the motor-side swash angle bearing is garbage (made with plastic separator) and there is a plastic pressure valve inside them that breaks and blows open. Hope you can figure it out.
Plastic pressure valve inside the hondamatic? I know there are some check valves inside, but they are all metal from what I have seen. I have heard the pressure can run about 5000psi inside the hondamatic, so I certainly wouldn't think they would use a plastic pressure valve...then again you wouldn't think they would use bearings with plastic cages either. So :confused:
 

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Discussion Starter · #10 ·
All I know is the motor-side swash angle bearing is garbage (made with plastic separator) and there is a plastic pressure valve inside them that breaks and blows open.
That is true for the 2001 to 2004 (1st gen) Rubicon Hondamatic units, and probably what took out his original. But not true for the 2005 to 2014 (2nd gen) Rubicon Hondamatics. No plastic carrier in those bearings. @skyhiranger were you able to verify the used unit you bought is good?
Actually, the bearings look fine in my original hondamatic...no broken plastic cages anyway. The pistons inside the hondamatic came out of their bores and got crushed up by rolling around inside the hondamatic and damaged other internal parts of the hondamatic.
Are you sure about the plastic cage on the bearings in the later hondamatics? According to everything I have read/heard/seen...the later hondamatics use the same crappy bearing design.
No, I have no way of 100% verifying the hondamatic is good. It was sold as good on ebay (take that for what it's worth). I spoke with the seller after I installed it and had drive issues (wasn't sure at the time where the issue was, so I questioned if and how they actually tested the hondamatic, to verify it was good before they sold it). He said he personally drove the Rubi before they started tearing it apart (had been wrecked and bent the frame, that is why they were parting it, according to him). Seemed like a stand up guy and has 100% positive feedback, so I really had no reason to doubt him.
 

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All I know is the motor-side swash angle bearing is garbage (made with plastic separator) and there is a plastic pressure valve inside them that breaks and blows open.
That is true for the 2001 to 2004 (1st gen) Rubicon Hondamatic units, and probably what took out his original. But not true for the 2005 to 2014 (2nd gen) Rubicon Hondamatics. No plastic carrier in those bearings. @skyhiranger were you able to verify the used unit you bought is good?
Actually, the bearings look fine in my original hondamatic...no broken plastic cages anyway. The pistons inside the hondamatic came out of their bores and got crushed up by rolling around inside the hondamatic and damaged other internal parts of the hondamatic.
Are you sure about the plastic cage on the bearings in the later hondamatics? According to everything I have read/heard/seen...the later hondamatics use the same crappy bearing design.
No, I have no way of 100% verifying the hondamatic is good. It was sold as good on ebay (take that for what it's worth). I spoke with the seller after I installed it and had drive issues (wasn't sure at the time where the issue was, so I questioned if and how they actually tested the hondamatic, to verify it was good before they sold it). He said he personally drove the Rubi before they started tearing it apart (had been wrecked and bent the frame, that is why they were parting it, according to him). Seemed like a stand up guy and has 100% positive feedback, so I really had no reason to doubt him.
Sorry, poor assumption on my part from reading into your post #1, yes you stated pistons were bad and I extrapolated and figured the bearing was the start of all the damage.

And sorry to @retro as well. I've read through this thread here many times: https://www.hondaforeman.com/147-rubicon-500/149697-hondamatic-rebuild-3.html#post3106946 and I thought for sure I had read 2005 on up did not have bearing with plastic carrier. But the guy that has rebuilt dozens of these confirmed otherwise.

So now I will be letting my brother with an awesome shape 2006 know that he actually does have a ticking time bomb under him. I had mislead him on that one as well.
 
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Discussion Starter · #12 ·
Sorry, poor assumption on my part from reading into your post #1, yes you stated pistons were bad and I extrapolated and figured the bearing was the start of all the damage.

And sorry to @retro as well. I've read through this thread here many times: https://www.hondaforeman.com/147-rubicon-500/149697-hondamatic-rebuild-3.html#post3106946 and I thought for sure I had read 2005 on up did not have bearing with plastic carrier. But the guy that has rebuilt dozens of these confirmed otherwise.

So now I will be letting my brother with an awesome shape 2006 know that he actually does have a ticking time bomb under him. I had mislead him on that one as well.
Actually, your brother might be ok. From what I have heard/read, the main issue causing hondamatic failures in the 2001-2004 Rubicons was the oil pump. The relief valve would stick and cause low oil pressure, which in turn would cause the hondamatic to self-destruct, if ran with low oil pressure long enough.
Granted, there have been some people that have had issues with the 2005+ hondamatics, but the issues are not nearly as prevalent, since the oil pump design change in the 2005+ Rubicons.
And since the hondamatic in the 2005+ Rubicons wasn't changed, it stands to reason that the oil pump was the main culprit in the hondamatic failures in the 01-04 Rubicons.
 

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Discussion Starter · #13 ·
Here is an update.
I haven't made any changes yet, I've just been checking/testing wiring, sensors, plugs, etc. to try to eliminate it being an electrical issue. Such as a sensor not sending back proper data to the ECM, and therefore the ECM not changing the swash plate angle correctly for the current speed and throttle position.

I test rode the Rubicon again. It was about 75* out. With a cold engine and running ESP mode, it initially felt like it shifted firmly into each gear and the drive between the engine and tires felt very efficient. I was running it in low range (I don't have enough open area to ride in high range and go through all the gears). I accelerated using half or three quarter throttle, held it there and shifted through the gears as the speed topped out in each gear.
I rode around for 5-10 minutes or so, using both ESP and auto modes in low range and running up and down through the gears. The shift firmness started getting progressively worse, after the first 2 or 3 rounds of 1-5 shifts. The shifts started feeling mushy and there was a slipping (reduction of drive) feeling between the engine and the tires. Finally it got to the point that in any gear other than first there was noticeable slip (lots of RPM, but lagging acceleration). In ESP mode it didn't seem to be as bad, but it was fairly easy to tell something wasn't right.
I tried to take some video, so you guys could hear the noise it makes when it "slips". But I haven't used Photobucket since they stopped allowing linking and now evidently they don't allow you to upload videos anymore, so I'll have to see about finding another place to host the video, since I don't see where I can upload it here.
Based on the latest test ride experience, and all other things I have tested/checked/changed, it appears to me it is oil related. In that the oil gets too thin and there is an oil leak internal to the hondamatic and it just doesn't convert the energy from mechanical to hydraulic back to mechanical properly/efficiently. Agree? Not agree? Other thoughts?

Unless you guys have any other ideas or suggestions on what I can test/check, or what the issue may be, I plan on draining the Rotella oil out this weekend, pulling the front cover, probably taking the clutch apart again and checking it for issues, and putting it back together and trying some Valvoline 10w-40 conventional oil made for wet clutch applications, to see if it has something to do with the synthetic Rotella oil.
 

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Sounds like a hydraulic issue to me too, going by what you explained. I doubt that a change in motor oil will make up enough difference to be a noticeable improvement though. I'm guessing its leaking somewhere... an o-ring, gasket, cracked or porous casting, etc. The noise you mentioned has left me wondering if it has to do with a piston or two...? I can't think of anything that could make noise hydraulically, except a leaking hydro piston assembly due to the pressures reached in those. I'm interested in what you learn next for sure. Thanks for keeping us updated!
 

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Just a passing thought... next time you test it out can you get a few oil temp figures as it progressively becomes worse? You might get temps using an IR temp gun aimed at the oil cooler lines if ya got one? Severe internal leaks will cause the oil to overheat rapidly is why I ask...
 

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Discussion Starter · #16 ·
I guess if it ends up being an issue in the hondamatic, then that will likely tell me whether the guy I bought it from truly and thoroughly tested it before selling it. Since I had issues from the very first time I ran the engine after I installed it.
From what I read elsewhere, the pressure inside the hondamatic ranges from 5000psi to 8700psi, dependent on engine RPMs. That is a lot of pressure to try to contain.
Yeah, if it is an oil leak somewhere, then changing to a different weight/brand of oil won't fix it.
I do have an IR temp gun. I'll see about getting some temps off the oil cooler lines, next time I run it.
Although, I am not sure that will really tell me anything, unless I have a baseline to compare the temp vs. time.
 

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Discussion Starter · #17 ·
Here is the video I took to try to capture the sound when the Rubi loses drive (it actually doesn't lose drive altogether, but it takes a lot more RPMs than what it should to get it to move).
It is kinda hard to hear the sound, but it starts at about the 5 or 6 second mark in the video, where I start to give it some throttle, while going up an incline.
It appears the video is "being processed" (whatever that means). So hopefully it starts working shortly. If not, I guess just check back later, since I am not familiar with flickr and how they do things.
https://www.flickr.com/photos/[email protected]/shares/3uRi4M
 

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Here is the video I took to try to capture the sound when the Rubi loses drive (it actually doesn't lose drive altogether, but it takes a lot more RPMs than what it should to get it to move).
It is kinda hard to hear the sound, but it starts at about the 5 or 6 second mark in the video, where I start to give it some throttle, while going up an incline.
It appears the video is "being processed" (whatever that means). So hopefully it starts working shortly. If not, I guess just check back later, since I am not familiar with flickr and how they do things.
https://www.flickr.com/photos/[email protected]/shares/3uRi4M
I can hear the "squalling" you've been referring to. I know you mentioned the condition of the centrifugal clutch in your first post. Did you verify the pad material on the weights was within service limit? And not burned smooth? Or prior owner didn't install stiffer stall springs (doubtful he did). I agree you're probably on the right path with something hydraulic, but just want to eliminate clutch for sure.
 

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Discussion Starter · #19 ·
Since my original post in this thread, I have since replaced the outer clutch drum, weights and springs with all new ones. The weights and springs were not OEM, but OEM equivalent replacements (less than half the cost of OEM Honda). So I really don't think it is a clutch issue at this point. But I can pull the front cover, when I get ready to tear into this again and I am hoping I can see/tell if the new clutch has been slipping.

The squalling/noise you hear in the video is not nearly as bad as it was with the old clutch outer, weights and springs. If I would have taken video of that, there would have been no problem hearing the clutch then. I did measure the old clutch parts when I removed them and the drum and fiber material left on the weights appeared to be within spec. I think the springs may have been a little out of spec (I know they were stretched longer than the new springs). The old clutch fibers were very dark brown, where it appeared the clutch had slipped a lot in the past, and they didn't seem to want to hold oil very well (they almost appeared dry, when I removed them, but everything else was oily, so it's not like the clutch wasn't getting any oil).

So since new clutch components did not fix all my issues, I am thinking I originally had 2 issues...one was clutch, which should now be resolved. The second is this unknown issue which is appearing more and more to be an issue with the hondamatic.

Where I am at, at this point is trying to verify where the issue is before I tear the engine apart again. I really don't want to tear the engine apart in "hopes" I find something wrong. Because if I don't, then what do I do? I really don't want to replace the hondamatic again (because if I do, it will likely be with a brand new one=$$$$$, so there should be no doubt it is good). If I check the brand new oil pump I originally installed and it is exactly the same as another brand new one, then that likely won't fix the issue (which I don't think there is an oil pump issue anyway, since the oil pressure is never below spec, even when I hear this squalling/slipping noise from the engine).
 

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Since my original post in this thread, I have since replaced the outer clutch drum, weights and springs with all new ones. The weights and springs were not OEM, but OEM equivalent replacements (less than half the cost of OEM Honda). So I really don't think it is a clutch issue at this point. But I can pull the front cover, when I get ready to tear into this again and I am hoping I can see/tell if the new clutch has been slipping.

The squalling/noise you hear in the video is not nearly as bad as it was with the old clutch outer, weights and springs. If I would have taken video of that, there would have been no problem hearing the clutch then. I did measure the old clutch parts when I removed them and the drum and fiber material left on the weights appeared to be within spec. I think the springs may have been a little out of spec (I know they were stretched longer than the new springs). The old clutch fibers were very dark brown, where it appeared the clutch had slipped a lot in the past, and they didn't seem to want to hold oil very well (they almost appeared dry, when I removed them, but everything else was oily, so it's not like the clutch wasn't getting any oil).

So since new clutch components did not fix all my issues, I am thinking I originally had 2 issues...one was clutch, which should now be resolved. The second is this unknown issue which is appearing more and more to be an issue with the hondamatic.

Where I am at, at this point is trying to verify where the issue is before I tear the engine apart again. I really don't want to tear the engine apart in "hopes" I find something wrong. Because if I don't, then what do I do? I really don't want to replace the hondamatic again (because if I do, it will likely be with a brand new one=$$$$$, so there should be no doubt it is good). If I check the brand new oil pump I originally installed and it is exactly the same as another brand new one, then that likely won't fix the issue (which I don't think there is an oil pump issue anyway, since the oil pressure is never below spec, even when I hear this squalling/slipping noise from the engine).
Hmmm. That's interesting the squalling got noticeably better with the new clutch, but not totally resolved. I know you are going to monitor temps, which is good and I would too. And you and retro don't think oil will change anything, and I agree too. I run T6 in my 400AT Hondamatic as does my brother in his '06 Rubicon. But you know what? It sure can't hurt to try a different oil? I would try the Rotella T4 15w40 which is also JASO MA and would be thicker than the T6. Or you could try Honda 10w40. Some specific machines just like to favor one oil over another. I've seen crazier things.
 
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