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Motorcycle Bottom End Rebuild | Part 2 of 3: Crank & Bearings


This is Part 2 of the Split Cases, Crank and Crank Bearing Replacement Video. Please refer to Part 1 for the previous dis-assembly. Using the Tusk Case Splitter. We’re going to go ahead and put this on the ignition side. And there’s a couple important things to remember with this tool. First of all it needs to be level with the case. So the tool pulls it level, and it also needs to be centered on the crank. And the bolts don’t need to be tight. You don’t want to damage the sealing
surface because the pressure will not be on the case half. It will be actually on the bolts. And you go ahead and use a ratchet. And start to press that
splitter and you can see that it’s starting to split the case. And you want to make sure that the case is coming apart parallel. If it doesn’t sometimes you need to take a rubber mallet and tap the backside. So that it comes out together. You don’t
want it coming off at an angle. It needs to all come out parallel. Once you’re done with it go ahead and remove the puller. And pull your case half off. And as you do this you want to make sure that there’s no washers that have stuck to the inner races of the bearings on the other side. So you don’t misplace them. And now you can see everything exposed, there’s your transmission and your crank. We’re going to go ahead and pull the transmission out. Get your countershaft and your main shaft. Make sure and try to keep
them all together. All your shift forks And then lay them out. Make sure and check for washers, and your shift drum also. Now’s a good time to check for wear on your cogs. Now we’re going to go ahead and push the
crank out from the other side using our splitter again What we’ve done is we’ve mounted this to the clutch side, and we’re just pushing that crank out. As you can see it comes out nice and straight. Make sure
once again that your puller is centered on the crank. We’re going to inspect our rod. At this time. Now side to side movement is OK but it’s just the straight up and straight down movement is what you want to check for. And if it is loose. Pro-X or Hotrods makes a complete crankshaft assembly. Or you can have your crank rebuilt by a machine shop. Now it’s time to remove the crank bearings and seals. To start off with we’ll remove the seal retainers And we’ll flip it over and use a punch or a screwdriver and pound that seal out. We also want to remove the centering
dowels. So we can lay the case flat on our clean work area. Because we don’t want to mess up the sealing surface of that crank half, the case half. Use a large socket. And pound out the main bearing. It may take some considerable force. We’re going to go ahead and clean it up at this point. We want to make sure and get some new quality bearings to install. And what we need to do is we need to use, it’s called sweating it in. And you heat up the case half and then you’re going to freeze the bearing. And so we want to heat this up, we’re just using a propane torch. You want to heat it up until water just barely sizzles. It’s about two hundred degrees. And we’ve had our bearing in a little cooler with some dry ice to shrink that bearing up. You want to use some gloves to protect your hands. This bearing is very cold at this point. We want to wipe off the ice so this slides right down in there. There’s some condensation that’s formed and some ice. And you actually just drop it right in. And if you’ve done it right it should just slide right in. Now we’re installing our seal, our crank seal. But it might be a good idea to do this later and you install the crankshaft. Here is the seal retaining clips. Use some medium strength threadlocker on them. You don’t want any of these bolts coming loose inside your case. We’re lubing up the outside of the seal for the other side. And this also, you can install the seal after your crankshaft has been installed. Here’s all your parts laid out on your clean work area. They’re in order, they’re organized. We know how they’re going to go back in. Alright we’re going to start to install the crank. We’ve got our new bearings, were gonna go ahead and grease up the inner surfaces a little bit. We’re going to go ahead and sit the crank in the bearing. And flip the case half over. And install the crank installer. And there are several parts, adapters that adapts it to the end of your crank. There is an aligning notch that this tool goes down onto. Put the nut on the outside. Thread that on a little bit. Some cases you can actually just rest the puller down on the case just outside the bearing. But on this model we needed to use some bar stock. To hold it up and away from the boss’ that were interfering. The bar stock just holds it parallel to the case. Where there’s no interference. We’re gonna go ahead and start tightening the nut which will pull the crank in. And you want to make sure that the rod is up or where it needs to be so it doesn’t interfere with You’re going to go ahead and tighten that, and it pulls the crank all the way in to where it needs to be. This concludes Part 2. Please refer to Split Cases, Crank and Crank Bearing Replacement, Part 3, for additional assembly instructions.

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