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Bottom shock bearing

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Posted by: canyncarvr---------------------

Has anyone serviced their linkage and found the bottom shock bearing to NOT be bad?

I've replaced it..along with sleeve/seals...and find that it doesn't seem to last any longer than if I just soak/clean a stuck one to 1/2 way working and use the old seals.

I take it apart 2-3 times a year. Have been told by a bike mech that the bottom shock bearing in kawis has been a weak spot for about ever. Still...it's complete junk!!


Posted by: kdxquebec---------------------

same thing to me .I have to grease this bearing once a week!!!


Posted by: DAVE C---------------------

Are you talking about the bearing in the middle of the Uni Trak Arm? If so, I agree. I stripped my brother's down yesterday and it was completely gone. New Arm time for him.


Posted by: canyncarvr---------------------

One thing I've noticed is that the positioning of the bearing in the unitrack arm is critical. There won't be enough room for one of the seals to fit properly if the bearing isn't centered. There is only one groove machined into the arm that you can use to gauge placement of the bearing...but not two grooves (one on both sides) for comparison.

I use a depth guage to make sure the bearing is smack dab in the middle of the arm.

Doesn't seem to have anything to do with how long the bearing lasts. If the bearing was off-center, I imagine wear could be even worse!

I guess once a week service would ward off damage..but that seems a bit severe to me. 'Hang on a bit while I fill-up with gas..and grease my unitrack link..."


Posted by: kdxquebec---------------------

it take to me about 4 min. to grease this little bearing.I dont have any others idea to preserve this needle bearing.I think that the concept is not verry good because same as you , my seals lips dont go fully in the pivot.. scuse my English I am french!!


Posted by: canyncarvr---------------------

I wouldn't have the unitrack clean enough (for me) to start taking it apart in four minutes!

As long as your dogbone bolts enter from the LH side, you could just take off the one dogbone to access the bottom shock bolt. I've put my bolts in from the RH side cuz it's easier to assemble. If there isn't a trick to getting this bearing to live for awhile, maybe I'll go to the grease every week idea...and turn my bolts around.


Posted by: BRush---------------------

First time I greased it, six months after installing all new bearings & seals it was fine. I just did it again two weeks ago (after a year’s interval) and I had to replace it. It was marginal – would not turn freely and the sleeve had marks on it from the rollers - indicating not a lot of movement, and some moisture penetration. I’ve been thinking about it off and on since then.

This bearing is small and it has to handle the entire shock load, so for that reason I’m guessing the designers specified a full-complement needle bearing because they have a nice high load rating. The problem I’ve found with small full complement bearings is that 1) it’s hard to get grease in between the small tightly spaced rollers, and 2) Unlike the other larger linkage bearings, there’s not a lot of extra space for the grease anyway.

The location does not help. This bearing sits relatively low, exposed to muck and water and vulnerable to power washers. Not much we can do about that, except not go nuts at the car wash.

Besides grease, I slather the sleeve and mounting bolt with antiseize. Some evidence exists that when the bearing gets a little stiff, the sleeve and mounting bolt may become the rotation point instead of the bearing. I remember someone posting to that effect a couple months ago. Mine looks like it might have done that too, and I wonder if others have seen this?

One thing I want to do is to see if there’s a better quality bearing than Koyo and give it a try. Just to see if brand makes a difference. Something else that would be interesting would be to give a caged needle bearing a try on the theory that they turn more freely and there’s more room for grease. Load is a concern, but in browsing though a few catalogs I found some higher quality precision cages needles in the right load rating, but so far they are 24mm OD instead of 22 (other dimensions are the same).

Btw, once I cleaned up the old bearing in penetrating oil, it seems fine and I may keep it around for a spare.


Posted by: kdxquebec---------------------

dear old member,take off the tie-rod bolt on your "dog bone" then take off the shock bolt .Put down your ''dog bone'' and you are ready to grease your shock bearing (4 min) I hope you understand me and i hope i understood you!


Posted by: canyncarvr---------------------

Specs for the bearing: (kawi pn 92046-1192)
16x22x12..inside-outside-length

Those numbers from the buykawi website parts breakdown.

BRush: What good is it to have a needle bearing in a place that doesn't rotate much? The TOP shock mount also handles the entire shock load...and there's no bearing there at all!


Posted by: BRush---------------------

Quote:
Originally posted by canyncarvr
What good is it to have a needle bearing in a place that doesn't rotate much? The TOP shock mount also handles the entire shock load...and there's no bearing there at all!


Apples and oranges. The load bearing ability of the bolt (upper or lower) is not an issue. What I'd like to know is why is the shock bearing so much smaller than the other linkage bearings? Anyway there's a big difference between not rotating much and not rotating at all. I do wonder if a plain bushing instead of a bearing would be all that much worse?


Posted by: DAVE C---------------------

You guys have obviously been through this before. Any recommendations on where to order a kit containing all the bearings and seals for a rear end re-build for my brother's bike ('96 200)? I will also need the uni-trak arm and all the sleeves. That bike went way too long without service! Thanks.


Posted by: 70 marlin---------------------

my 99 held up. 96 took out the rocker when it failed. 1 for 1


Posted by: canyncarvr---------------------

BRush: I don't understand your response (apples and oranges), so maybe my question wasn't clear.

I wasn't questioning the load bearing ability of the bolt. Fact: The top mount of the shock has NO bearing. The bottom mount does.

Your comment of the bottom mount having to, '...carry the entire load' also applies to the top mount (with NO bearing).

It's not a matter of rotation..the top of the shock rotates no less no more (duh..the same as?) than the bottom.

So..why not use a bushing in the bottom? Get one the same size as the bearing so you could still use the seals to kinda sorta help keep junk out. Maybe still use the sleeve (or not..I don't know which would be better).

So..I'm asking the same question. Why not use a bushing in the bottom shock mount? HOW could it be worse?

Current (just called..all in stock!!) prices:
92049-1330 seal $4.99 (need two)
92046-1192 bearing 9.50
42036-1248 sleeve 5.00

I just talked to a local bearing wholesaler. He told me that he could find no bearings listed in his metric book with the given dimensions.

Called my local friendly machinist about making a brass sleeve of the bearing dimension (still using the sleeve, then). He asked me to call him back in a bit. I'll let you know what the deal is.

If 'we' find someone to machine 'us' a bunch..who wants to 'buy in'???

DaveC: re kits
The unitrak arm I think can come only from kaw. The problem kit-wise is that no one makes a kit for '..all the bearings and seals..'. Pivotworks for example makes a shock kit, a swingarm kit and a linkage kit. The bearings they have in their swingarm kit are NOT caged. Cleaning them means taking all the lil rollers out, sticking them back in the cage one by one.

You might want to take it apart first to see if you really need EVERYthing. The swingarm bearings seem to fare better than parts of the linkage. Some judicious cleaning and greasing may save you some $$.


Posted by: DAVE C---------------------

canyncarvr,
Thanks, I just checked out PivotWorks kits. Man they are spendy! I already stripped the back end down and it needs everything! Pretty bad I must say since I just did my own and they were great, but I take better care of my stuff. You are correct that the swingarm bearings fared the best, but they are severly rusted and need replacing. A couple more rides and I think he would have been in serious trouble!

The Pivot Works kits seem nice, but I would really like some caged needle bearings so that future breakdowns are much easier. Anyone ever come across these?


Posted by: BRush---------------------

Quote:
Originally posted by canyncarvr
BRush: I don't understand your response (apples and oranges), so maybe my question wasn't clear.

I wasn't questioning the load bearing ability of the bolt. Fact: The top mount of the shock has NO bearing. The bottom mount does.

Your comment of the bottom mount having to, '...carry the entire load' also applies to the top mount (with NO bearing).




I was confused by your comparison of the bottom bearing to the top bolt with respect to load. I’m not denying that forces are exerted on the top mount. My point was that what happens at the top mount is irrelevant when discussing bearing life , since it has no bearing. Also, I’m not sure that it’s true that the top shock mount rotates as much as the bottom, since the linkage rocker imparts a greater range of motion to the lower one.

That said, I don’t know why a bushing would not work. Do you think brass would hold up? At the very least, it would be an interesting experiment. I’d think you’d want to keep the sleeve to have as large a bearing surface as possible.


Posted by: Lutz---------------------

Quote:
If 'we' find someone to machine 'us' a bunch..who wants to 'buy in'???


I'd be interested in this possibility, as long as the price per unit would be "competitive." Let us know what you find out.

It would be interesting to see how the suspenision would work with a bushing in place of the bearing. The only problem I could forsee is accelerated wear on the bushing; I think that the bottom shock bearing sees more rotation than the top shock bushing because of the linkage. The top bushing only sees a rotation based on an angular change in shock position, but the lower bearing sees rotation based on the angular change in shock position as well as angular change in rocker arm position.

The thickness of the bushing may be a problem if it has the same dimensions as the original bearing; i.e. it may not be thick enough for the stress applied to it, and may crush. It might be best just to replace the sleeve and bearing both with a single, thicker bushing. In this case I think it would be more important to maintain crush strength than a larger wear area; it is far more likely for the bushing to fail first by crushing than by frictional wear.

With all that said, I don't think it would really be a problem with proper lubrication. Many suspension components in cars, atv's, etc. use bushings with no problems, so I don't see why we couldn't do it in our case.

Regards,
Lutz


Posted by: canyncarvr---------------------

hey mr. fizzicks!
Quote:
I’m not sure that it’s true that the top shock mount rotates as much as the bottom..


I see this as an impossibility...that a straight line as is the shock from top to bottom can rotate ANY differently top-to-bottom. Move the top in a 10º arc...the bottom is going to move in a 10º arc. There is no fulcrum in the middle to multiply movement. Even though the length of the shock changes..the angles don't.

If you have an explanation that gives the top of the shock less º of movement compared to the bottom, I'd like to hear it. The linkage rocker imparts a larger º of movement to the OTHER points of rotation due to a lever/fulcrum deal, but that doesn't apply to the shock mount.

...I think??

Still haven't had a chance to talk to the machinist. I'm going to take him a bearing and sleeve so he'll know for sure what size of bushing (brass I guess) I'm after.

BTW..the size of the sleeve doesn't seem to match the ID of the bearing spec #s?.

I'll see if mr. wilkey is willing to shed some light on this.


Posted by: canyncarvr---------------------

Lutz said:
Quote:
The top bushing only sees a rotation based on an angular change in shock position, but the lower bearing sees rotation based on the angular change in shock position as well as angular change in rocker arm position.


Well, then...

That makes it all perfectly clear. It helps to run through the motions starting with the WHEEL instead of starting with the SHOCK.

I apologize for the prior stated stupidness. Dang!! I USED to be able to THINK! Too many concussions, jaw breakage and skull fractures!! (I have to have SOME excuse )


Posted by: dirt bike dave---------------------

While I have not tried it myself, riders of '97-'99 CR250's replace the lower shock's needle bearing with the spherical bushing from the upper shock mount.

On the CR, the spherical bushing is reported to last much longer. The needle bearing in this location wears out much faster than the other bearings in the linkage. I would check to see if the KDX's upper shock bushing will fit the lower mount as well.


Posted by: JonV---------------------

a pressure washer will kill these quick.

use the bel-ray waterproof and use it often. i do my sons 85 once a week, and mine about once a month. all other bearings are fine but the lower shock eye bearing always takes a beating.


Posted by: BRush---------------------

Quote:
Originally posted by Lutz


The thickness of the bushing may be a problem if it has the same dimensions as the original bearing; i.e. it may not be thick enough for the stress applied to it, and may crush. It might be best just to replace the sleeve and bearing both with a single, thicker bushing. In this case I think it would be more important to maintain crush strength than a larger wear area; it is far more likely for the bushing to fail first by crushing than by frictional wear.


That would be the dilemma. If you go with the larger bushing and no sleeve, then the smaller diameter bolt will concentrate the force pressing against the bushing ID and perhaps oval it out. If you retain the sleeve and use a thinner bushing, then the force is spread out over more surface area, but the bushing is thinner so maybe it will crush sooner. I think to really know for sure you’d have to try both methods and see which way works best.


Posted by: canyncarvr---------------------

dirt bike dave:
The upper mount bushing is part of the shock. It's not a piece individually available from kawi.

JonV: Pressure washing isn't much of an issue in this case. The bearing is fairly well protected by the linkage (pull rods).

A truck mechanic asked me about teflon bushings in this case. Can teflon be machined as bronze can be? Anyone know a metalurgist type that might have an idea for something other than bronze for this application?

I just picked up some hydrotex grease for my replacement this time 'round. Supposed to stick incredibly and be impervious to practically everything.

Maybe I'll have a bushing ready for next time around.


Posted by: dirt bike dave---------------------

Quote:
Originally posted by canyncarvr
dirt bike dave:
The upper mount bushing is part of the shock. It's not a piece individually available from kawi.

.


Uhhh, it is Part #92092. Go to the page for shock absorber. Don't know if it will fit the linkage, but its worth a try.

http://www.buykawasaki.com/site/Veh...&ModelYear=2002


Posted by: Kootenaycat---------------------

I just serviced my new '01 220 (before even riding it). I heard from so many of you how little grease the factory uses, and you were right! Thanks for the advice. And, after reading the above, I will service my lower shock bearing weekly too!
I noticed that in the swingarm there was enough room to put zerk fittings right into the alum swingarm. I read the zerk mod where they go into the ends of the bolt, but why not drill right into the swingarm? I may give that a try next service.


Posted by: canyncarvr---------------------

dbd:
Of course you are correct. Speaking from the basis of what I recall is obviously a mistake. I 'remembered' looking into that very piece before..didn't think they called it out. sheesh... Too bad they don't give the specs for its size.

BUT...the buykawi site has a new face..different from just yesterday! Much more of the screen is used for information, less for useless graphics. Glad to see that part.

kootenay:
When the last thread started regarding swingarm zerks, I 'remembered' THAT (ha! ) to be a 'through the swingarm' approach. It didn't end up that way. Seems to me that the swingarm approach (if you're going to do it anyway) is preferable because it would leave the sleeve as-is, and the area available for the injected grease to GET to the bearings is MUCH moh better.

Who wants to drill a hole in their unitrack for the bottom shock bearing? Because of the size of the unitrack seems you'd need to drill the oil hole at an angle to the zerk. Might not be enough metal to put a zerk in near the bottom. I'm taking my linkage apart this week to replace the bottom bearing..maybe I'll give that a shot......

Noticed that the PivotWorks shock kit for the kdx is $35. The general description of the kit includes a whole lot of stuff the kdx doesn't have (TWO teflon bearings...FOUR seals...)..unless they've changed some stuff? Although it says 'bearings where applicable', maybe they replace the bottom roller bearing with a teflon piece?

I just called rockymountain..they couldn't tell me what was in the kawi kit and didn't have a number to contact PivotWorks directly.


Posted by: DVO---------------------

Kootenaycat: I did the zerks thru the s-arm, will send you pics tonight if you wish. Works great!
Canyncarvr: I haven't gotten around to checking out the shock bearing zerking yet but the outer race of the bearing would be solid no? By that I mean it would extend the full width of its bore(minus the seals) so there would be no space to inject grease without drilling through. In this case there is an argument for through-the-bolt greasing but if I recall correctly, there is no space ta the side for a zerk to extend out(would get torn off by the tie-rods I think).
As far a thru the bolt zerking of the s-arms goes, it would solve the bolt rusting-to-the-sleeve problem 'cause this would get just as much grease as the bearings. I'm gonna do mine but leave the sleeve un-drilled so I can do both separately and guarantee greasing(maybe the grease would exit the side of the sleeve before flushing the bearings and I already have my s-arm done.)


Posted by: r.2 stroke---------------------

Yeah, my lower shock bearing was toast when i last greased my linkages,i replaced it with a FAG brand bearing of the same dimensions(german made i think),and repacked it and everything else with Castrol boating grease(waterproof and very sticky)
Might check it again this weekend


Posted by: BRush---------------------

CC, I was browsing through the McMaster-Carr catalog today. They sell a bronze plain bearing
16mm x 22 mm x 16mm, that would only have to be trimmed down to a 12mm width to be a perfect fit. You can get it in either SAE 660 or SAE 841 bronze. The 660 being stronger and the 841 being oil impregnated. Cost: a whopping $4. There are also some very interesting synthetics: Vespel and Rulon, but they don’t seem to come in metric sizes.


Posted by: canyncarvr---------------------

dvo:
As you say..the bearing is CLOSE to the full width of the assembly when the seals are included. And there isn't room for a fitting in the bolt.

Haven't done it yet (just got all the parts I need over lunch), but I figured to drill a hole at an angle from the machined groove inside the knuckle to the hole the zerk is in. Probably end up running the bit through the same hole with the zerk in to make sure there's a grease access path. I don't know where there is room to put a zerk in the first place...but I've got the stuff if I find a place for it! I know it's all pretty close down there (say from the knuckle to the swingarm). Maybe there isn't any reasonably accessible place to put a zerk.

r.2:
I'd appreciate hearing how it looks. Have a source for that bearing?

BRush: (thanks for the mcmaster-carr input!)
So, that would be with the idea of continuing use of the sleeve. Do you think the thickness (or thinness?) of the bushing would compromise its viability? Would you choose oil impregnated or not?

They also have graphite filled bushings of the same measure. What about those? Too many choices..too much grey matter needed to decide which!!

heck...by the time I'm done this weekend, I'll be buying a new unitrack arm!!

GIMMEE THAT 1/2" JOBBER-THINGAMABOB!!!


Posted by: DVO---------------------

Kootenaycat: Try this;
http://www.dirtrider.net/forums3/sh...&threadid=39005
Take a look at the last 3 pics; The first is the right hand side, it's the easiest place to access for greasing. In pic two, the grease you see is escaping out the inside front. You can't see it in this pic but it exits out the bottom outside also, completely flushing the bearing. Cool eh? The third pic is the back of the s-arm just infront of the tire where the tie-rods attach. .Very easy to do.


Posted by: Canadian Dave---------------------

CC I read a thread in the MX forum a while back. It seems that grease selection is critical with this bearing. I wish I could remember what brand grease they were recommending but at any rate it was a grease intended for heavy load applications. There were a number of KX owners responding that indicated it substantially increased the life of the lower shock bearing on their KXs. It might be worth a post in the MX forum.

David


Posted by: Kootenaycat---------------------

DVO, thanks for the link to the pics! Upon looking at the diagram just above the 3 pics, I now wonder how much grease is worked in between the needle bearings! The grease will take the path of least resistance, meaning it will go past the bearings and out the seals (easy route) before really penetrating the space between the needles (dead end!). I think the zerk idea is great as long as you still disassemble couple times a year to inspect, clean and pack. With the zerks, at least you can almost guarantee to pump the water out if done right after every ride, which should make the bearings last forever!


Posted by: Tantrum---------------------

Kootenaycat,

If you are going to consider Zerking The Swingarm, check out my site at
http://www.kdxmodifications.com

One of the advantages of going thru the pivot bolt, is that when you do decide to dissasemble, the bolt cannot be rusted to the inside of the whole assembly. Im sure you have seen threads pertaining to beating the heck out of the bolt just to dissasemble. I too looked into zerking right thru the swing-arm, but thought that there could be a possibility of ripping off one of those little buggers on the trail. Another advantage is that when the whole assembly is full of grease, it is nearly impossible for water to intrude the bearing area.

Cheers,
B.


Posted by: canyncarvr---------------------

re: zerking the bottom shock mount.

Not enough room behind the unitrack. Won't clear the swingarm. Could put it in from the top, but no reasonable access with a grease gun. Link could be sculpted some just in front of the bearing to allow for flat mount of fitting. That would allow easy access, but I'm not real crazy about removing metal on the link to get the zerk to fit flush.

I just replaced the bearing/sleeve/seals...again. Used some of that purple hydrotex grease I mentioned earlier. It's pretty sticky stuff!

Re: placement of bearing in link (and subsequent seal fitment)

On closer inspection with my calipers, seems the bearing should NOT be dead center in the link. <edit> This doesn't compute..although it's the way it turned out. The metal inside diameter of the seals seat against the sleeve. There shouldn't be any lateral force against the bearing.


I still put my link bolts in from the RH side for easier disassy..more difficult access to the shock mount, though.

Broke my 14mm socket on the linkage bolts! THAT hurt when my knuckles played interference with my 16" ratchet! And, yes...they WERE torqued to 65lbs last reassy (four days ago).


Posted by: DVO---------------------

Kootenaycat;
Don't worry about grease missing the bearings, it inevitable.
Tantrum; no chance of the nipples getting torn off, they're well hidden. Actually, I thought they'd stand a better chance of getting torn off in your application. But I'm still gonna do it.


Posted by: DAVE C---------------------

Well, I just checked the price for the UniTrak Arm and the dealer wants $140! :scream: Glad it didn't happen on my bike! I am trying to convince my brother to let me take it to a machinist and put in a brass bushing. That would save him the $140 for the arm and $35 for the shock bottom bearing kit from Pivot Works. Thanks for the ideas guys!


Posted by: canyncarvr---------------------

Cost from the dealer for bottom shock stuff (here anyway) $28. That includes sleeve, bearing, seals.


Posted by: DAVE C---------------------

canyncarvr,
I guess that is b/c my dealer SUCKS! I went in yesterday and asked for an inexpensive RK chain (specifying non-Oring) and he comes back with a $135 DID X-ring O-ring chain. Then I asked if he had a 520 master link instead. He said for what chain. I told him it was a stock chain from a '99 KDX 200. He proceeded to tell me, quite vehemently I might add, that no bike comes stock with a master link. I then proceeded to prove him wrong on his own bikes. Then I got into the whole bearing kit thing and UniTrak Arm and I had to find the parts for him on his own computer! Don't think I will be buying anything there ever again! I have to give him a little credit though, he did manage to scrape together an el-cheapo KMC "bottom of the barrel" chain. Price - $35. I can get that chain for $17 from any website.


Posted by: canyncarvr---------------------

It's easier to laugh if it's you and not me...but that's really funny!! Yeah..in a very pathetic sort of way...but funny, still.

Ha!..A 520 master link..for what chain?

Better luck with some other dealer. Nothing short of 'moron' to describe yours.


Posted by: DAVE C---------------------

Oh, I forgot. He told me last night that NoToil dropped them as a dealer. It can't get any worse than that!


Posted by: Tantrum---------------------

Sounds like your Dealer and my Dealer must be brothers, or had the same business administration class. He told me that all I had to do in order to repack my stock silencer was to drill out the rivets. Uh, Have you ever seen the stock silencer on a KDX dood?

B.


Posted by: r.2 stroke---------------------

Finally got round to looking at the bottom shock bearing.....sweet as!last time i greased all the linkages & bearings was about six months ago...a few rides and washes since then,can recommend Castrol Boating grease(lithium based i think)



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