While tuning my bike ('72 125 CMF) last Saturday, bad sounds came out of the engine. Disassembly revealed a broken wrist pin bearing. I've never ever had a wrist pin bearing fail! This motor had approximately 2 hours on fresh piston/bore.
http://s250.photobucket.com/albums/gg276/ernie7711/?action=view¤t=sachs125writpinfailure159.jpg
Looking at the failed part and comparing to a new and used bearing revealed that the cage on this bearing is dinky and it may not have been heat treated. If you have any of these type bearings (dull metallic finish) beware!
http://s250.photobucket.com/albums/gg276/ernie7711/?action=view¤t=sachs125writpinfailure163.jpg
It is possible that I damaged the bearing upon assembly but I didn't have any difficulty putting it together – but who knows. To be safe check your replacement parts very carefully. Since the motor had parts go through the bottom end, I swapped motors with a spare I had (thanks Doug Wilford). We will be at the races in Ocala.
Ernie P.
Chattanooga, TN
Ernie,
Although I can't tell from the picture for sure, the top of the piston looks like detonation damage/pitting. It may have contributed to the shock damaging the wrist pin bearing. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
Mike, Interesting observation. I didn't notice any signs of detonation while riding under any/all load conditions. Jetting was purposefully fat (Bing 30mm w/148 main jet), yamaha lube 32:1, and timing was set at 2.3mm BTDC (running digital PVL with 4 degrees of low speed advance),150 psig cranking pressure) Take a closer look at piston. Damage appears to be caused by broken bearing cage that passed through engine and did "tap dance" on top of piston. Small dark spot in center of piston is machine tool center. Challenge my assumptions - I don't want this to happen ever, never!
http://s250.photobucket.com/albums/gg276/ernie7711/?action=view¤t=sachs125writpinfailure168.jpg
Ernie P.
Chattanooga, TN
Damage does look to be debris made, I'd definately be trying to score the "older" style bearing if they're available.
Ernie,
Yes, it's a lot more obvious in the last pic that the piston was damaged due to debris/parts "tap dancing" on the top of the piston. The other pic wasn't clear enough to see that well on my computer. I agree with Dan about using the older pin bearing if you can locate one. I would call Doug and inquire about what type he uses in his engines. I am sure that he would be able to recommend a more durable replacement. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
What is the IDxODxW of the bearing? Wiseco has good bearings and pins available separately. Definitely looks like the cage failed to me, which is very strange. I work at a Motorcycle/PWC dealership and with the jet skis I thought I had seen every type of failure there was, but I've never seen that before.
Brian
Mike, Dan & Brian,
I think if you look real close at the failed bearing you will see that is lighter in color as compared to the ones on the right. A possible cause would be this caged bearing got passed the inspectors without being heat treated. Brian you are correct this is a failure you hardly ever see. I have seen this type of failures, but it has been due to wear and not to a problem in manufacturing. Just my take.
Ron Carbaugh
I noticed the different color but I was not sure what it meant, sometimes too much heat can cause color changes, but in this case I dont think the engine got that hot. It could just be because the cage is apart and has no rollers in it, but it appears to be more lightly made too. I think Ron is on to something, I'd bet on either improper heat treating or no heat treating at all.
Brian
Bearing dimensions: 19mm OD x 15mm ID x 19.7mm long.
While measuring the bearings, I discovered a major difference. Although the good and outlaw bearings have the same overall dimensions, the outlaw bearing has needles (rollers) that are 2mm shorter. Big deal? I think it may have been the killer characteristic.
http://s250.photobucket.com/albums/gg276/ernie7711/?action=view¤t=sachs125writpinfailure172.jpg
Since the wrist pin bearing is free to float between the piston bosses, the bearing can shift to one side. As photo below shows, this could cause edge loading and overload due to less surface area. With the correct bearing, the rod is always fully supported on the rollers even at extreme displacements. Again, I advise everyone to carefully examine 'spare parts'. There is much opportunity for interbreeding over these last 30+ years ... and many mismatched and bogus parts floating around. My inattention to detail killed my best motor!
http://s250.photobucket.com/albums/gg276/ernie7711/?action=view¤t=sachs125writpinfailure176.jpg
Ernie P.
Chattanooga, TN
I dont think there should be that much float. Even if the bearing floats to one extreme side or the other you should be able to see both ends of the roller. That is easily double the amount of wiggle room I would have expected to see. Are the cages different widths too, or is it just the roller that is different on the outlaw bearing? I think it might a good idea to try to find a slightly wider caged 19x15x20 or 19x15x21 bearing.
Brian
On the KTMTalk.com website a similar failure occurred with a piston pin bearing. The following link, if it works, will show you some pictures of the failure.
Rocket
http://ktmtalk.com/index.php?showtopic=267071
Ernie,
It looks like the cage on that one is made in 3 or more pieces?
The ones we have to look at here are made from one piece I think.
That may be the rub. we did have one needle bearing wear out after 15 mins. of use in 2003. We thought it might be the oil we were trying out. So we did not use that brand again.
Sounds like we need to watch which bearings we buy. Sachs Book calls for a 15 x19 x 20.
Does anyone know which manufacture supplies good wrist pin bearing's?
The old OEM part had much more metal around the needles than the new bearings we have bought the last few years.
John D.
Wiseco sells wrist pin bearings separately and they have one in 15x19x20. I think they cost about $10.
Brian
John Consolidated Bearings show K15x19x20 .... I dont know the manufacture ... you would have to call and ask and also check lenght of roller if that is important ....BT
Brian Taylor
Brian,
The supplier wont be the problem . It will be the bearing manufacturer.
Quality control. Wrist pin bearings we have bought in the past have never come in a box like M20 or 6202's with FAG or SKS or.... on the box.
I looks like it would be good to know who is making needle bearings now.
Not a good turn of events.
John D.
I had the same thing a year ago in the opening round Arizona. Piston failure around wrist pin area self destructing everything with only 5 laps of practice and some break in run time.EVERYTHING was new..a bad chain reaction that moved my little bike closer to the door.
I know...I'm gonna get it for this post! Have a good weekend guys![8D]
PS- Firstturn, the seat shipped out today...TB
Couldn't be that you ride like a wildman.[:o)]
Lew Mayer
Tom,
Good to hear from you. We had a great weekend at Ocala under sometimes difficult conditions and circumstances. Marty Tripes and Chuck Sun were in attendance. You too are a Legend and I hope will grace us with your attendance sometime this year. But I'm NOT going to loan you a bike to ride;). I loaned our new baby Berkshire to Brain "Black Cloud" Kirby to ride and it came back in less than perfect condition. You and Brian have similar riding styles and histories of mechanical difficulties ... He rode 4 different bikes and guess what – he broke all 4! (just poking a little fun guys). Brian did bring home a moto 1 victory in 100cc Expert. More later ...
Ernie P.
Chattanooga, TN
I broke two Maicos, one Can-Am and one Penton. Not a good weekend, but I did take the first Penton moto victory in the 100cc class. Unfortunately I could not back it up in the second moto.
Brian
Good to get a report guys thanks. How was the weather? No Mud???
How did Chuck look? Saw him about 5 years back at Glen Helen.
Ernie & Brian,
Win lose or draw thanks for you being there and thanks for the report.
Tom,
Looks like you have a new Friend with Brian....
Thanks Guys (Christopher too) for representing Penton.
Ron Carbaugh
Tom,
No rain, no mud but the dirt was like Saddleback which since you raced there you know exactly what I'm talking about. They are not kidding when they called it Hard Rock MX. Saddleback was my home track the last three years it was open so I didnt have trouble, but hard pack like that is rare in the SE and it takes a while for folks used to soft red clay to learn how to ride lumpy blue groove.
Chuck looked great, and rode great all weekend. He won Post Vintage CC overall Friday on an '84 RM500 and rode a couple of classes both days in MX. He had good battles in Sportsman 250 in Vintage and 50+ Exp in PV. I think he won all of them, but I'm not sure.
Marty Tripes was there too, and I have to say he is the nicest guy you could ever meet. He was truly honored that we had not forgotten him and his accomplishments. I really like that all us regular guys who used to only read about our heroes or see them at the occasional race (that includes you Tom) can now give something back to them and let them know how much they inspired us. It was really cool.
Brian
Ernie, way to go with 4 laps! and a win in Sportsman 200 Inter.
Brian, you must not have broken the Canned Ham too bad for a hot 4 lap pace in 200 expert.
Our own Chuck Reuben and Chris Phillips took 1,2 in Classic Inter CC.
"Wildman" Dan Pagel and Glenn Berry had first and third in Open 200 novice.
Pentons were well represented in CC.
Lew Mayer
I broke 1st gear in the Canned Ham on the sighting lap. Most AHRMA CC races I never use 1st gear all, but this race I really needed it. On the third lap right after you left the MX track and went back into the woods I sunk the bike up to the tank in a mudhole right in front of Glenn Berry who was also stuck. It took me three minutes to dig the bike out and get it restarted.
Brian
Ernie, Brian,
It was nice to meet you folks. Hard Rock was a tricky track for 100 's
I hope we can meet again sometime this year at one of the events.
Putting names with posts was nice. How many total 100's showed up ?
John D.
John, it was great to meet you too. We talked for a short time at New Blaine, but it was one of those group pow-wows standing around looking at a bike (the rear shock mounts on your Penton I think) and we never got introduced.
There were 9 total 100s, two Experts, four Intermediates, and three Novices. Kid Christopher and I were the only Pentons.
Brian
Here is an update on wrist pin bearing. I had one fail 2 weeks ago in 2 mins run time on a new bore and piston. Thanks to Ernies warning when i heard it ticking i pulled the top end and checked. Sure enough the wrist pin was worn hard on one end ( the cage was a gray color replaced it with one from Al that was a dark brown black ). Replaced the pin and bearing and ran 140 miles in 2 days on that engine. Top end is still quiet as a new bike.
Brian did some research for us on needle bearings and found this web site. It would be worth copying and putting in a safe place.
http://www.schaeffler.com/remotemedien/media/_shared_media/library/downloads/tpi94_de_en.pdf
Brian thanks a lot,
John D.
This hit my bike on sunday , I missed the posting info and it was to late. LG
Invisible. "That cannot be seen". Mysterious, also. Due to
most recent experiences, but not being trained in metalurgy. I
have learned (and seen) failures in rods, gears etc. that
in my opinion have failed because of age. Just my two cents.
Doug,
No doubt that age plays a factor, but I think "Substandard" replacement parts is a big problem also. After the fact, I found out that my piston pin failure was due to bad bearing. Same with repop selector keys. My latest "discovery" is durability issues with replacement M20 bearings (China?) with the polyamide cage. I'm now using NOS eastern european bearings with brass cages. Besides the obvious spalling of the outer race, just look at the physical differences – larger inner race, smaller balls, machining chatter - poor metallurgy. Guys, examine your replacement parts very carefully. They are not all the same.
(http://i250.photobucket.com/albums/gg276/ernie7711/m20polyvsbrass.jpg)
(http://i250.photobucket.com/albums/gg276/ernie7711/m20outerracezoom.jpg)
Ernie P.
Chattanooga, TN
Hey Guys,I just lunched the motor on my 125 last weekend and come to find out the wrist pin bearing was the culprit.What's the latest on which top bearing to use and who has them?Dark Brown is the cage color to use???I know i have some new ones just want to make sure this doesn't happen again-it figures,i finally after 40 years get my Dad to come see me race and i make 2 laps of practice:(.Thanks,
Ric
ric emmal
Hey Ric,
I believe the bearings Al sells now are Wiseco, which are very good. You might give him a call and see what the latest news is.
TEAM PENTOVARNA
Kent Knudson
Kevin Brown
Gary & Toni Roach
James & Adam Giddings
Dennis & Cory Buttrick
Thanks Kent,I'll give him a ring.
Ric
ric emmal
Just ran across another wrist pin bearing grey in color-new part but the rollers were falling out of the cage(each roller has a separate slot so i know the're not supposed to) and the thing just looked kind of cheesy.Don't know where it came from but not using it.Just a warning to look at all your parts before installing-it could save you a lot of grief! Later,
Ric
ric emmal
I think some folks were using the wrist pin bearing that came with the re-made rod kits. DO NOT USE those wrist pin bearings. Those re-made rod kits are from China and even though the rods seem to be OK, the bearing are not. Just my thoughts. If you have a re-made rod kit, open it and look at the wrist pin bearing, they are a lighter shade of grey and looks to have NOT been heat treated and as we all know, the quality of the metal used in china is NOT near what it needs to be.
Donny Smith
Paragould, AR
Part of the problems Ernie and I identified with his failed wrist pin bearings (donno if they were Wiseco or Chinese) was two fold. One is the bearing roller itself was shorter side to side, so as the bearing moved it would put excessive load on the "shoulder" of the roller, and probably causing the cage to fail. Also, the rollers themselves were larger in diameter, and fewer of them in the cage, where the originals were much smaller in diameter and quite a few more per bearing (2-3) which disperses the load more evenly between rollers.
When I did the top end on my 100 I did not use a new bearing because I could not find one with rollers the width and diameter of the original, only the ones like Ernie had fail. I have since found that a '2011 KTM125 has the same size bearing as the Sachs 100/125 and KTM 125/175 in Pentons. I would bet that is a darn good bearing, but I have not ordered one to inspect it yet.
Brian
Just ran across another wrist pin bearing grey in color-new part but the rollers were falling out of the cage(each roller has a separate slot so i know the're not supposed to) and the thing just looked kind of cheesy.Don't know where it came from but not using it.Just a warning to look at all your parts before installing-it could save you a lot of grief! Later,
Ric
ric emmal
I think some folks were using the wrist pin bearing that came with the re-made rod kits. DO NOT USE those wrist pin bearings. Those re-made rod kits are from China and even though the rods seem to be OK, the bearing are not. Just my thoughts. If you have a re-made rod kit, open it and look at the wrist pin bearing, they are a lighter shade of grey and looks to have NOT been heat treated and as we all know, the quality of the metal used in china is NOT near what it needs to be.
Donny Smith
Paragould, AR
Part of the problems Ernie and I identified with his failed wrist pin bearings (donno if they were Wiseco or Chinese) was two fold. One is the bearing roller itself was shorter side to side, so as the bearing moved it would put excessive load on the "shoulder" of the roller, and probably causing the cage to fail. Also, the rollers themselves were larger in diameter, and fewer of them in the cage, where the originals were much smaller in diameter and quite a few more per bearing (2-3) which disperses the load more evenly between rollers.
When I did the top end on my 100 I did not use a new bearing because I could not find one with rollers the width and diameter of the original, only the ones like Ernie had fail. I have since found that a '2011 KTM125 has the same size bearing as the Sachs 100/125 and KTM 125/175 in Pentons. I would bet that is a darn good bearing, but I have not ordered one to inspect it yet.
Brian
Thanks Donny/Brian/All-Sounds like the solution was sitting in my dining room all along(my 2010 KTM150xc-it sleeps in the house).I'll go down and pickup a bearing for it-between that and the one Donny is sending i ought to have it covered.Thanks,
Ric
ric emmal
I have (18) OEM Sachs #0632-111-001 Upper Rod Bearings available. Get em' while you can... I have had no luck locating any quantities of the 0632-111-001
OEM Bearings in the past year. Thank you, Tom G.
[email protected]
I have been using Suzuki RM-125 wrist pin bearings for years in sachs motors with no problems.I can find the part # if needed.I think they are from early 90s model.