Which bearings do you need? Connecting rod generally comes as a kit with connecting rod, bearing and crank pin. This is because the pin and inside bore of the connecting rod are bearing surfaces. Someone might offer the bearing only but I'd not do it alone as the pin and rod will have commensurate wear.
Main bearings: the ball bearing I have in my notes as 40x90x23 mm SKF 6308, but not certain if that's by my own measurements or someone provided. Single row ball bearing so simple enough to source.
The cylindrical roller bearing comes with the left crankshaft half if memory serves. I've not needed to source one of these separately that can recall. This bearing runs in a steel insert in the left side case so damage there requires case half replacement. Very unusual to have a crank rod bearing or left bearing fail so would make certain. The right side is a "replace if in there" precaution IMO.
Then there are the balancer bearings and suppose you might mean transmission bearings but the request doesn't specify.
Hoping Tom will weigh in because think he was smart enough to record the numbers...don't ask.... (face palm). If memory serves they are all readily available from a bearing supply house. Might be worth PM'ing him in case he hasn't seen this thread.
OK, here's the dealio. I looked into this when I blew up my motor and the deal was odd enough that I couldn't decipher my notes, so here's a re-do on past research: The upper left bearing measures 20X47X14, which makes it equivalent to a 6204. However, it is marked as an SX04A37. That ain't no kinda bearing I ever heared of. Norm? Got any clue-drops you can pour on me?
The fiche calls for a SX0415, which I ain't never heared of, either. When I Google it, though, it comes back as a Kawasaki 92045-1188 which agrees with the fiche. Googling a SX04A37 brings back only one sensible page, from NOC. That page says the data is missing.
So, there is something special about that bearing, but I don't know what it is, and I don't know if fitting a 6204 would be the right thing to do.
The good news is that all these bearings are readily available and aren't real expensive. Even the mysterious (to me) SX bearings are only $13 from Partzilla.
That bearing is a seven ball rather than 8 as one would expect for for a 6204. This will mean a heavier cage or such modification. Likely there were design concerns that the cage would break from vibration... that's what came to mind so started looking along those lines- special bearing.
The quick check I made indicates that this is an OEM manufacture only "S" means special dimensions or features and 37 means that it is the 37th design type used in this bearing series. I will see if can find someone with NTN who is willing to dig to find out the special features of the design. I wonder if the internal clearance is greater because of a larger interference press fit into the case + the heavier cage? I don't recall a locating pin on any of the KLR balancer bearings (to keep the bearing from turning in the case) but forget and confuse with other engines as see so many apart and KLR guts not that frequently. One reference indicated an update of the OEM number from "SX04A37" to "TM-SX04A37" and that "TM" indicates a long life material. The "SX" was last produced in 2006 while the "TM" prefix is still being made.
All I can find but will try the forbearance of NTN to see what else.
FWIW, there's no way I'd use a 6204 in place as have seen this kind of substitution often go bad with other bearings such as a special ball size in the same inner and outer race dimensions. Having a balancer cage fail (the most common mechanical failure to a single row ball bearing, IME) would be nasty as the balls often run over the loose cage pieces and spread the outer race, breaking the surrounding structure.
Can't find anything on the SX0415 but since that's likely the 15th design of the 04A, it may be very old and because the design numbers aren't related to one another, just that they indicate some design change to the basic 04A, it could mean anything.
I'll continue to order those sorts of bearings from Kawasookchi. I think that the bearings inside were ordered by the owner so must be why I don't recall this issue.
It would be useful to know if the dimensions have changed between Gen1 & Gen2. I'm too would up with family stuff right now to even think straight but hope that we can get to the bottom of that as it may point to something useful.
I wonder if the reason for the "TM" was because of some failure pattern (unlikely, IMO) or just the wish by Kawasaki to improve the product?
If someone who has one in hand would please measure the cage thickness, that might be useful information, if only to clarify the difference.
Tom, any chance that the failure one which you encountered was an eight ball (i.e. wrong) bearing? Wish there was more time to look into this as someone else had reported a failure at one point so would be interesting to PM in case he hasn't seen this thread.
I will see if can get further with NTN when get a bit of time. I'm certain, from doing these kinds of investigations in past, that we will find that this bearing is only made in batches for exclusive supply to Kawasaki because there is no general market sufficient to support a general production and sale.
When I keep old bearings, they just sit in the box taking shelf space. When I throw them out, regardless that they are a 6203-2RS and common as garden soil, there was always a reason I wanted that one. Never, ever fails.
When you mentioned seven balls I went out and took a quick look, but in my haste counted the balls in the output shaft bearing rather than the balancer bearing. Later in the evening, while chatting with Tristan, I realized my mistake.
That bearing is dimensionally identical (to a casual examination of OD, ID, thickness, ball count, and race gap) to a 6204, so whatever makes it special remains a mystery.
I wonder where I got the seven balls? I've not had trouble counting my balls before but maybe over six confuses me. ;-)
I'll have to start over to see if can work that out. Other than from interest, I doubt that we will find any option excepting to buy from Kawasaki but one never knows what value can be derived until one follows to the end.
I recall your comment about liking to rev to 7,000 RPM but wonder if that might be easier on the bearing than running at a lower RPM where a harmonic might apply greater forces to the bearing? Wondering is as far as I will get on this one but someone may have insight so throw the thought out there.
We spoke late last year about NTN's SX04A37 bearing. This item has been
replaced by TM-SX04A37. Although the SX04A37 bearing design has the same
dimensions as a 6204, it is a special design with special outer ring
features not interchangeable with a standard 6204 design.
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