bottom end

lots of crud in that pickup screen,id do a serious scrubbing of the bottemend before it goes back together

its coming completely apart and getting hot solvent tanked, then bead blasted.

I clean the oil passages with pipe cleaners.

jzanutto wrote:

all my 2 strokers have the segmented crank with ball bearings. To me plain bearings seem to be a step backwards. I know it eliminates having special crank tooling and a special service manual just for the freekin crank, but anyone care to make some intelligent comments here about why plain bearings?

Journal bearings handle much more power than ball bearings. with a pressurized film of oil, in theory the surfaces dont actually touch, with a roller or ball there is contact all the time and a very focused point of contact.

You know Z1 sells a cam chain master link and master link tool. Buy a new cam chain, and install their master link, and you don't have to rebuild the bottom end. If you want to rebuild the bottom end, "just 'cuz", then you might want to see what's available from Kawasaki before splitting the cases, or you'll have to use old parts.

www.buykawasaki.com is a great parts availability website, and can tell you if the parts you need are "Active", "Active Limited Quantity", or "Cancelled". Most internal roller bearings can be purchased at a bearing house to save you some money.

Not to steal your thread, but I am doing a complete tear down, "just 'cuz" on one of my spare GPz550 engines, I plan on installing the best of my aftermarket goodies including the 615cc kit I've had all ready for 2 years now. I'm wondering about the crank and rod bearing "shells". There are 3 sizes of crank bearings and rod bearings available from Kawasaki. After I emory-cloth polish the crank and rod journals, what's the recommended clearance for oil? Should I just go with what the Kawasaki Factory Manual suggests for oil clearance on both rod and crank bearings of .004" or 0.10mm, or is there some other magic number?

Keep us posted on your build up.

I dont like plastic guage, it lies to some extent.
Babbit bearings have been around a long time, and have been tried under the most extreame conditions.
The roller bearing engines are a lot more complicated to set up and that would add a lot of expense to the engine mfg process.

Unless something is really worng with the bottom end. a good cleaning and careful reassembly will produce an engine that will last for a lot of years

If one needed to order a set of bearing shells(Charlie Babbit Style), other than plastigauge, how would you know which size/color to order? Inside bore gauges are hard to measure in the middle of the case, once bolted together. Not to say you're wrong, but I'd recommend to anyone, if you have the cases apart, and the bearings are available, why not just replace them while you're in there? New bearings run retail for about $10.00 each half shell. That equates to $180.00 for the 5 crank journals and 4 rod journals on my 550. I wouldn't reinstall the same old bearings, but that's just me.

dman3998 wrote:

jzanutto wrote:

all my 2 strokers have the segmented crank with ball bearings. To me plain bearings seem to be a step backwards. I know it eliminates having special crank tooling and a special service manual just for the freekin crank, but anyone care to make some intelligent comments here about why plain bearings?

Journal bearings handle much more power than ball bearings. with a pressurized film of oil, in theory the surfaces dont actually touch, with a roller or ball there is contact all the time and a very focused point of contact.

Yes, I remember in Engineering school going thru this. In theory, as the crankshaft rotates squeezes the oil film that becomes superstrong, not allowing the metal surfaces to touch. The faster it turns, the stronger the oil film. As you said before, in theory, there should not be metal to metal contact during rotation. The wear could only occur during the first turns of the crank, when engine is started, as there may be little oil and pump is just awakening. I believe all cars use also plain bearings.

I used to work in a power plant with big steam turbines, and the turbines rotors rode in huge plain bearings. Before starting the turbines, an electric oil pump would be started to pump oil inside the plain bearings before allowing the turbine to turn. If we had electric oil pumps in cars and motorcycles, started a couple of minutes before cranking, our bottom ends(engines) would last for ever.

Yes, and more the reason to let a turbo motor idle a little bit to allow it to cool down before shut-off, and also to let the spinning of the turbine shaft slow down as well. Pre-lubers, and after lubers work great, but can be overkill in my opinion.

thats good info guys. My entire bottom end will look like this when done. Then gloss black imron maybe

hugo wrote:

[If we had electric oil pumps in cars and motorcycles, started a couple of minutes before cranking, our bottom ends(engines) would last for ever.

They used to sell aftermarket ones for turbo engines in cars. The turbos would fail VERY early in life from city driving because at turn off, the oil flow stops and the heat in the turbine's bearings would boil the oil there. Then when you start it, the bearings were dry. I remember electric "pre" and "after" oilers that would keep oil flowing a while after the engine turns off and pump it up before you start it.

Looks nice an clean there jzanutto!!! What did you use, glass beads or sand as lasting media?

glass beads. Then lots of pipe cleaners in the oil galleys