Crankshaft/balance shaft bearings available from????

[KevinC]

Hi,

Does anyone know if the plain bearing caps might be available at a bearing or engine shop usually? They are back-ordered from Suzuki, and I have a race in a week and half.

I'll try tomorrow locally anyway, just wondering if anyone has had any success in the past.

Thanks!

[Bob Broussard]

I doubt if plain bearings are available from a bearing shop.
I've never had trouble getting bearings from Suzuki.
The part number is 12229-01D01
-0B0 (black)
-0D0 (yellow)
-0C0 (Brown)
I'm not sure which code is the green bearing.
To figure out which bearings you need, first look on the counterbalancer. There is the letter A or B on it. Sometimes you have to really try hard to see it on each of the weights. It's kinda painted on. All the ones I've seen are marked A.
Then look at the rear of the engine cases. There are several squares with A or B stamped on them.
The 2 upper squares relate to the counterbalancer. The 4 across the bottom are for the crank.
Here's the bearing chart layout.

case | crank/couterbalancer code
code |    A   |   B   |   C   |
A   | green  | black | brown |
B   | black  | brown | yellow|

Example: A on the counterbalancer
B on the left square means you need a black bearing for the left bearing journal.
The right side square is for the right bearing journal.
Each package of bearings only has a half bearing, so you need to order 2 packages for each bearing journal. Rod bearings come 2 in a package.
I have 2 packages of black bearings
and 4 of the yellows. Let me know if you need these bearings.

[Blueknyt]

ok i dont have a book yet and didnt  know it was such a jig saw puzzle for bearing halves from factory, Is there a Real reason for differnt sizes on one crank, or counterbalence? would it be that hard to machine everything to one size? i can understand cutting a crank and undersizing a bearing, but that many differnt sizes? i noticed that amoung my engine parts, i have what looks to be a GS450 counterbal shaft, but it has Roller bearings on the ends.  If this could be done to the crank i think it would be a boon

[bob]

Is there a Real reason for differnt sizes...

Yeah, there is a good reason.  Bearing clearances are critical to engine durability & noise.  Piston to cylinder clearances are also critical.  You want just the right amount of clearance - too little & you smoke the bearings or scuff the pistons, too much & the engine will be noisy, either "clunk" or dull mallet on wood kinda noises from the bearings & piston slap from the, uh, pistons.  The range of "not too much, not too little, but just right" is extremely small, on the order of a couple thousanths of an inch or less.
Some manufacturers try to get away with one size fits all, but in order to ensure durability they have to open the tolerance up toward the looser side.  This makes them susceptable to noisy engines which can reduce the "quality" sound (even though durability is OK).

[soapbox]
As far as a race engine goes, I've always built my engines with the green bearings, which give the loosest fit, regardless of what the codes on the crank & case call for.  My reasoning is that I don't care about a little more noise (I can't hear the engine over the screaming going on in my helmet anyway) and looser fits free up a tiny amount of power, make the engine run fractionally cooler & keep me at the loose end of the spectrum, away from the (tight) end which can be chancy from a durability standpoint.  Suzuki runs the bearing clearances a little on the tight side from the factory, IMHO, and when one is on the racetrack thrashing the daylight outa a poor little engine that was just designed to be a learner/commuter there's a bit more risk of failure due to oil starvation.  Also, even with the biggest journals in the case & the smallest journals on the crank or balancer & using green bearings, the clearances are still not so huge that there is the risk of running too loose.  Study your service manual & do a little math & I think you'll see that the loosest you can possibly get them is in the neighborhood of 3 1/2 thou, if memory serves.
[/soapbox]

Have you tried bikebandit.com for bearings??

I may have a coupla new green bearings around if you wanna borrow them.

Best of luck!

Bob

[KevinC]

Bob,

Thanks for pointing out the bearings only come one to a box. Crap!

I had gone through figuring out which ones to order. The green are 0A0. The green and black aare available, but I theoretically need 1 set of the brown and they are back-ordered. I had not thought of running a different size, but I'll just get and extra set of black or green.

Thanks Bob!

[Blueknyt]

what im asking is, arent all the Saddles and crank mains machined to same diameter? i can understand spining a bearing and polishing the crank, and honeing the saddles to put in a .005 undersize bearing shell. but from factory the bearrings should all be same diameter.

[bob]

All the journals are machined to the same nominal dimension, but there is variation in any manufacturing process.  The result is that in any group of theoretically identical parts, like a batch of cranks, say, all dimensions will vary slightly from part to part.  So, for instance, the crank main bearing journal diameter is nominally 32mm.  In reality they can vary from 32.000 down to 31.976mm & still be considered acceptable for use.  What happens is that the possible variation in diameters sets up the possibility that the clearance between the bearing once installed in the case & the crank journal can vary more than is safe for the engine.  The solution is to make bearings of different thicknesses that essentially "shim" the gap to an acceptable range.
BTW, the service manual calls for a standard bearing clearance of .020 to .044mm.  This is most likely this tight to try to keep the bottom end quiet under usual operating conditions.  The service limit is .08mm, so apparently Suzuki thinks their engine is still safe at that clearance.  I don't believe it's possible to even achieve this loose a fit even with the largest case, the smallest crank & the thinnest bearings.  I like to run my engines as loose as safe but will still give the least friction & heat.  So, a 32mm journal should be in the .05 to .06mm clearance range, IMO.  So,I just run the thinnest bearings (green) & call it good.  YMMV...