Author Topic: Crank seals for Dummys  (Read 15152 times)

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Crank seals for Dummys
« on: October 15, 2012, 03:38:05 PM »


220 Posts Posted - Oct 18 2004 : 10:29:36 PM
I was scanning my old email and this is from Sledkawi. I take no credit for this but I used it and it is right on the money . How to change them without pulling the top end apart.

Okay, here we go.
Remove the engine. drain the oil from the gear case on the clutch side of the motor. remove the gear case cover. once it is off, remove the center gear from the gearcase, pay attention to the washers on both side of the gear. Also remove the shaft the gear sits on. Next remove the bolts that secure the oil pump to the engine. Now remove the nut holding the gear on the oil pump shaft. To remove the gear and pump, just tap the pump shaft with a hammer and the gear and pump should fall out. Now we go to the other side of the motor. First remove the starter if there is one. Next remove the pull starter. Now remove the bottom pulley for the fan belt and remove the belt. Next remove the four nuts that hold the fan housing and motor mount to the engine, and remove the housing and mount. Now remove the large nut that hold the flywheel onto the crankshaft. Once this is removed, you will need a puller of some sort to remove the flywheel from the crank. You can probably use a harmonic balancer puller, but I just made up my own. Do NOT use the bolts from bottom pulley to mount your puller, they are not strong enough. You will need a stronger grade bolt. Once you get the flywheel off you must remove the stator assembly underneath. Be sure to mark it's position before removing the two screws that hold it in place.You wll have to feed the wires from the stator through the engine case, or you can wait till you split it. Now flip the motor on it's top and start loosening the bolts that hold the two halves together. Be sure to stagger your pattern and just loosen a little at a time until they are hand loose. There are 8 large bolts, and two small ones I believe. Once they are out you can very carefully try to tap the two halves apart. Be very careful where you tap or pry, so you do not damage anything. They should come apart fairly easy. Once the crankshaft is exposed, take o look at it and you will see a spacer on each side of the center seal. There will probably also be a shim on one side or the other, up against the spacer. Be sure you do not lose this shim, and pay attention to where it is located. It could fall out during seal change. Now the seal on the stator side of the crank is real easy to remove, Just lift the crank assembly up just enough to get the old seal off. For the clutch side it is a little harder to do. You must first remove the drive gear on the end of the crank, also there is a washer that sits on top of this gear. Don't lose it, and remember where it goes for re-assembly. This gear is just pressed onto the crank. To get mine off, I just used a small drift and a hammer. I positioned the drift behind the old seal, and against the back of the gear and kept hitting it until it came off. You must keep turning the crank to get the gear to come off evenly. Once the gear is off you can lift the crank again and remove the now badly damaged seal. Be sure to pay attention to which way the seals are installed so you get the new ones in properly. Clean the seal areas and the engine halves REAL good before putting it back together. Install the new seals the same way,( lifting the crank), and also, make sure you don't lift the crank too far up and pop the rings out. Only lift it enough to remove and install the seals. Now to put your crank drive gear back on, I would just use a socket that fits over the shaft and tap the gear on until it rests up against the shoulder. Make sure you put the washer back onto the crank gear. Coat the outside of the seals and the engine halves with proper sealant and put the halves back together. DO NOT USE SILICON SEALER ON THE HALVES. Use Proper sealant. I can't remember what it's called. I think it's made by Yamaha. Check with your local shop to be sure. Put your halves back together and make sure they fit together good. When you tighten your crankcase bolts, make sure you do it a little at a time and work in a staggered pattern. I don't know what the bolts should be torqued too as my manual doesn't say. Put your oil pump and drive gear back in. Put your center gear and shaft back in, making sure to put a washer on each side of it, and install the cleaned gearcase cover. I also put sealer on the cover, just in case. Well, I hope I didn't forget anything, but who knows? The rest of the assembly is pretty self explanitory, so have fun and good luck.

Waiting for SNOW!