TXC 250 main bearing failure, engine noise

[ray_ray]

That is some good info ... If those retaining rings are there for this reason, it shows the company is aware of the issue and used this bandage to prevent the cases from being toasted each time this happens from a spun bearing housing ... better than nothing ....

My bike is not over 10Gs very often on each ride ...almost never on trail rides and not too often on tracks ... I added 1T to the front sprocket (14\50) also and this helps the bike pull more (with speed) and not REV out sooo quickly ...maybe this has saved my mains ... I've been afraid of valve issues caused by the high RPMs....

If I could stop my bike REVing at 9999Gs, I'd do it ... there is not too much more up there that I really need ... I was told once that this is hard wired in the bike and can't be changed .. ... at tracks sometimes forget to shift and do the over REVs and this is totally rider error...

I'm glad you guys are having such good luck working on them ... I plan on keeping this bike quite a few more years ...

What about the bearings your buddy is talking about? Whats the story there ....

 

[Mike Kay]

Consider the FAG Bearing part # 6206.2ZR.C3

Its got the stainless steel seals. Remove one side to allow oil in. For an all steel bearing this is as good as it gets. Forget China. Forget the French OEM bearings. Any shop can machine the 1x2 mm groove.

Dont use the rubber seal (black color) bearings. As the rubber can come off allowing metal in, and changing the lubricating oil pressure off the journals.

The older 250's are a 450 with a smaller head, so its all overbuilt. Hence they last. But yeah even Huskys break. Sorry yours did. I had one go with only 5 rides on it. Had another last 3 Baja 1000's...

Get the FAG 6206.2ZR.C3 --harder to find, but worth it.

 

[ray_ray]

I found some on the web ... How sure are you on this part number before I fork over the big bucks?

http://www.ptplace.com/ptp/do/productDetail;jsessionid=C786BF74FFDCC7C1473E5F83519006BE.ptp_tom2?partNum=6206.2ZR.C2&srcCode=&doNewSearch=true&navbartype=Store&selectedcountry=USA&viewstore=false&selectedstore=FAG&bflag=false&selectedlanguage=English

 

[kiwitxc]

My valves looked great apparently & umm I've been friendly with the rev limiter over the last few months, obviously the main bearings were not so happy about that though.

Given we're due for a summer shutdown end of next week, I'll go OEM so I have the bike for races in the first week of jan.

Regarding the 6206 series of bearings, here's a pretty good skg list of what 2z & c3 mean ( 2zr has been replaced with 2z according to the FAG website http://medias.schaeffler.de/medias/en!hp.rn/6 ), in summary 2z is "shield of pressed sheet steel both sides" & c3 is "Radial internal clearance greater than Normal". Looks like all the manufacturers are going standard on their naming.

http://www.skf.com/portal/skf/home/products?maincatalogue=1&lang=en&newlink=1_1_16

 

[macwood]

great pics thats what my bearings looked like how do you put pics with these replies I thought just copy and paste but doesnt work for me. ps what do you think about the reason that bearings failed according to my mate the road racer, is quite sure because it always happened when there tricked up engines reved to 10k +

 

[ray_ray]

To post a pic off UR computer, just hit the 'Post Reply' or 'Go Advanced' button and then select the paper clip icon off the new menu options that will be displayed ... then just use that option to drill ('choose file' button, then upload button) to the pics on your computer ...

 

[ray_ray]

Consider the FAG Bearing part # 6206.2ZR.C3

Its got the stainless steel seals. Remove one side to allow oil in. For an all steel bearing this is as good as it gets. Forget China. Forget the French OEM bearings. Any shop can machine the 1x2 mm groove.

Dont use the rubber seal (black color) bearings. As the rubber can come off allowing metal in, and changing the lubricating oil pressure off the journals.

The older 250's are a 450 with a smaller head, so its all overbuilt. Hence they last. But yeah even Huskys break. Sorry yours did. I had one go with only 5 rides on it. Had another last 3 Baja 1000's...

Get the FAG 6206.2ZR.C3 --harder to find, but worth it.

Today, I was walking around Cebu City looking for some Slime when I saw a big FAG sign ... Walked on down and sure enough, it was a bearing store ... Freggin' accident as big as the day ....

They had the 6206.2z bearings ... No .C3 on the tail ... Will these fit and work in the bike? OR should I try to get them to order the bearings with the .C3 on the tail of the bearing number?

These bearings were not open either... there was metal around the outer case of the bearing hiding its internals ... this must have been the stainless steel seals?

 

[kiwitxc]

great pics thats what my bearings looked like how do you put pics with these replies I thought just copy and paste but doesnt work for me. ps what do you think about the reason that bearings failed according to my mate the road racer, is quite sure because it always happened when there tricked up engines reved to 10k +

I used google picasa and got a direct link to the image, pasted that into the image icon on the text editor.

The speed theory makes sense, the huskies rev pretty high, 12,500 I think, if not 12,750, that fast for those key bearings.

I'm hoping to get the bike back later this week and I'd like to get a look close up at the bearings, though I'm not sure if you'd pick visually a small change in shape which could cause things to go crazy.

 

[Mike Kay]

I know a bit about bearings.

My brothers bearing company: www.impactbearing.com
My dads bearing company: www.championbearings.com
I helped start both.

Neither will sell to the public, but both have lots of info on their sites about bearings, bearing failure, bearing ratings, etc.

I assure you this isnt a back handed way of advertising for them. They dont care about selling 2 little FAG 6206's to a moto bro. Both supply companies like Boeing, Tesla, Applied Materials, NASA, etc. Big orders, big bucks, big companies. I put this out just to have a reference place for moto folks with bearing issues in the future. Again-their websites have lots and lots of info about bearings.

--------------

FAG 6206.2ZR.C3 is the way to go for several reasons.

1) ya need a C3. The tolerances are loose enough to spin up fast, tight enough not to rattle themselves into pieces. Dont run anything but a C3. Tighter will create heat, rub the races to the breaking point, add to micro weld adhesion, and wont pass junk in the oil. Looser bearings will fail in a very short time.

2) ya need 2ZR - this is a bearing with metal shields (not rubber or teflon seals) on each side. For our bike ya just peel one of the shields off. It will destroy the shield, but thats ok. Folks have tried the rubber shields, they can fall off.
Also remember a "shield" is permanent. A "seal" is made to be taken off and then put back on again. Good for wheel bearings needing grease, bad for engine internals.

3) FAG is made all over the world. Brazil. Germany, and yes even China.
Same with SKF. Same with many others. No way to know where your bearings are from. But thats not the problem. The problem is Chinese knock off bearings are EVERYWHERE. Youve seen those Gucci bags and rolex watches for $20 bucks from China? Well its 1000 times worst in the bearing world. The box will look perfect, the bearing will look perfect, and the bearing salesman will pass a lie detector test, BUT ITS STILL A KNOCK OFF! And that means the internal clearances on the bearing are "potentiallly" all over the place. Hence bearing failure.

After spending lots of time (like 6 years) contemplating Husky main bearings, and working closely with my brother and taking all the above into consideration, we came up with the conclusion of all the "6206.2ZR.C3" type bearings available the FAG bearings are probably the least likely to be Chinese knockoffs, and they are certainly as good as it gets assuming they are the real deal. Thats based on whats been seen in the commercial bearing markets over the last decade.

SKF seem to be more often knocked off. But yes they are great bearings.

Look for a orange and black box. Hold your breath.

More than ya ever wanted to know about all steel Husky main bearings.

Just dont get me started about 6206 hybrid ceramic bearings...

 

[7point62]

...They had the 6206.2z bearings ... No .C3 on the tail ... Will these fit and work in the bike? OR should I try to get them to order the bearings with the .C3 on the tail of the bearing number?

Yeah, the C3 refers to the bearing's radial clearance (the amount of "play") and is often specified for engine bearings which are subject to high temperatures + speeds and are (usually) an interference fit. So if Husky specify C3 then C3 it must be.

These bearings were not open either... there was metal around the outer case of the bearing hiding its internals ... this must have been the stainless steel seals?

The "2Z" refers to those seals. No suffix would indicate an open bearing. If you need an open bearing in an emergency then those seals ping out pretty easily.

Bear in mind also that you'll have to find an engineering shop to grind the shoulder into the bearings to accept the retainers (bearing races are hard). Any shop with some sort of cylindrical grinding facility would be able to do it pretty easily, but I don't know how common they'd be in your locale.

Finally, I wonder if these batch of failures are due to counterfeit bearings finding their way into the food chain. There are folks out there who will copy anything - I've even seen fake brand name guitar strings recently...

edit: heh, Mike beat me to it...

 

[ray_ray]

Thanks and that is all very interesting ... I'll follow up see and about getting the C3 type bearing here ...

One of the things these guys do here is a lot of is fabrication via machine shops \ shade trees because labor is cheap and most everything other than food and housing is expensive ... I know of 2 shops now that might can do this work ... I'll just have to go by and check ...

 

[macwood]

Thanks for info on pics will try. I would never put anything in except for the C3 as they are specifically made for high speed and that is why they are failing. My racer mate said you can get high speed RACING bearings but havent checked yet but here is one race bearing site that I did find. they talk about mas produced bearings and their weaknesses
they claim to make ceramic balls that are that hard and precise to super high tolerances and thats what race engine builders use.
My mate says its the 10k+ thats killing them, I think my KTM uses rollers instead of ball for its mains?

http://www.northstar-ceramicbearings.com/whattolookfor.html

 

[macwood]

Thanks for info on pics here are 2 showing my mains bearing failure they are same as yours. Heres a thought , the 250 uses the same bottom end as the 450,510 and basically just put a smaller barel and head on. Maybe huski like me thought it would be bullet proof not realising the 12k rev factor, the 450 and 510 would not need to reach this high revs (unless riden by a complete idiot) and so the bearings not fail.

Other pic is of my worn woodruff key from camshaft drive sprocket which if it let go look out valves and piston. Drive train noise is considerably less now.

 

[aussie rider]

my 09 310 has just done the same thing. Will put in the fag bearings after I have had them modified and give you an update

 

[ray_ray]

Include pics if you can of the tear-down process....

 

[macwood]

good luck, you will find it a great engine to work on, I reused all the gaskets and had no issues and in fact the total cost of the repair was $24. Have done about 40 race hours since and no problems but stay off the limiter
cheers macwood

 

[ray_ray]

Sounds good mac .,,, I gotta get this work accomplished on my bike ....

 

[Planepower]

Just reading thru my owners manual - perhaps that could be why Husky reccomends bearing replacement at 40hrs (competition), 80hrs (limited power engine) or 10,000km. I think anything after the prescribed interval is a bonus, but bear in mind that parts dont last forever.

 

[MChammer]

Macwood - you're saying that these good FAG bearings everyone's agreeing need to be used only cost $24 and everything else was ok to reuse?

 

[MChammer]

Would someone be interested in marketing the good FAG 6206.2ZR.C3 bearings, already machined, to drop right in for a rebuild? The reason I ask is I don't have the knowledge to do this myself and would like to pull the motor on my 08 TE250/310 and give it to my local shop (Toy Tech) along with the bearing ready to go and instruct them to "use these bearings" for the rebuild. I fear if I give them FAG 6206.2ZR.C3 bearings that are not machined, they might not want to go to the trouble of finding a machine shop, and just use OEM bearing because they are ready to use.

Also - it's stated that one of the metal sheilds has to be removed from one side of each bearing....I assume it's the side facing in - meaning the side as seen on the pictures of macwood's case - which is also the side of the bearing that gets the machine work done to the shoulder of the bearing to accept the retainer plates?