Case splitting.
Posted: 10:29 pm Jun 01 2012
If you need to split your cases and think it is too big a job for you than read on. I think you will find it to be not as hard as it sounds.
I am posting how I did my crank bearings and seals. This is not the only way and this is not a complete bottom end rebuild as you will see. The pictures may not be that great but they are only intended to show the steps and not be a replacement for a manual. I only split the cases to replace the crank bearings and seals because I replaced everything else a couple of years ago and had a crank seal start to leak.
Tools you will need
1. A manual
2. A good torque wrench or two that can do inch pounds down to about 35 in lbs and foot pounds up to about 75 ft lbs
3. A case splitter of some sort
4. A freezer
5. A set of metric tools
6. Beer
7. A press is very handy
8. Will be mentioned in the post
Once you have the engine out of the frame it wouldn't hurt to clean off the dirt that is still on it.
Than the first thing I do is remove the cylinder. You can take the head off at this point to get a look at the cylinder.
You will need to remove the "paw" gear for the KIPS. This is the left hand thread that you have heard about. Don't forget to support it with a wrench so you don't break the pin for the governor.
Then remove the four nuts that hold the cylinder down and pull it off from the bottom end.
This is as good as any time to check the rod bearing for play. Side to side is fine. Up and down is bad.
Next step is to remove the right side cover.
Then remove the clutch spring retainer
Then the clutch nut
Pull the clutch assembly out and the primary gears then you will have this
Remove the kicker assembly and idler gear along with the shifter shaft. (You will need to at this point if you haven't already, remove the shifter.)
Now flip the case over and remove the flywheel cover
Remove the flywheel nut and use a puller to remove the flywheel
Remove the coil plate and the key way
Now remove all the bolts from the left side of the case and install your case splitter
You will see that as you split the cases the crank end will want to come first. I use a soft hammer to tap the cases so it pulls evenly.
After you have the cases split then it is time to remove the transmission gears. Start by removing the two shift fork guide rails
than the transmission shafts and gears should lift out with the shift forks still in place
Now you have a just about empty case half with the crank still stuck in there. It won't hurt to remove the shift drum at this point
I used a press to push the crank out
The bearings stayed in the case on both halfs so I just pressed them out using pine 2x4's as press plates so I didn't hurt the face of the case halves
now is the time to install the crank seals. I used the press again but this could be done with a hammer and the right sized driver
Once you have both crank seals installed You need to figure out how you are going to install the crank bearings.
Option 1 Warm the case half and freeze the bearings
Option 2 Use the press
After you have the bearings in the case it is time to install the crank into the right case half. I like to use the freeze and heat for this. Put the crank in the freezer for as long as you can. A few hours will work just fine. If you use a heat gun to warm up the bearing in the right case half it will help but be careful not to melt the seal. If all goes as planed than the crank will drop right in with a thunk as it bottoms out in the bearing.
Now reinstall the transmission in the case along with the shift drum
Install the shift forks and guide rails
Use a good case sealer
I bought, and am happy with the Tusk crank puller to do the next step. You might get by using heat and freeze or pulling with the case bolts but this crank puller works great!
Keep an eye on how things are going together while you pull the case halfs together. You want them to go as even as possible
Now that the cases are back together it is time to put all the bolts back in and tighten them. Then flip the bottom end back over and reassemble the clutch side
Once you get to the point of having the basket back on and the primary gears in place it is time to torque them down. What I have found to work well is to fold up a shop rag and jam the gears with it
I have found that with the rag in the gears and flat washers on the clutch springs you can tighten the clutch retaining nut easily.
Assemble the rest of the clutch
The next step is to install the right side cover. I find it easier to place the KIPS governor in the cover and hold it in place with the KIPS actuator shaft
Now back to the other side. Reinstall the coils and flywheel. We will get to tightening the nut later
Now clean up the cylinder and head and reinstall
Hold the shaft and tighten the left hand thread nut
Now it seems I don't have a picture for the tightening of the flywheel but you can either use a piston stopper, put it in gear and bind the chain, or before you reinstall the right side cover you can hold the nut on the right side of the crank and torque the flywheel nut.
While you have everything apart it is a good idea to clean and inspect every part that you touch and replace everything that needs replacing.
I hope this can help some one in the future. As of now I am done for the night I will probably make a few edits tomorrow but you get the idea.
I am posting how I did my crank bearings and seals. This is not the only way and this is not a complete bottom end rebuild as you will see. The pictures may not be that great but they are only intended to show the steps and not be a replacement for a manual. I only split the cases to replace the crank bearings and seals because I replaced everything else a couple of years ago and had a crank seal start to leak.
Tools you will need
1. A manual
2. A good torque wrench or two that can do inch pounds down to about 35 in lbs and foot pounds up to about 75 ft lbs
3. A case splitter of some sort
4. A freezer
5. A set of metric tools
6. Beer
7. A press is very handy
8. Will be mentioned in the post
Once you have the engine out of the frame it wouldn't hurt to clean off the dirt that is still on it.
Than the first thing I do is remove the cylinder. You can take the head off at this point to get a look at the cylinder.
You will need to remove the "paw" gear for the KIPS. This is the left hand thread that you have heard about. Don't forget to support it with a wrench so you don't break the pin for the governor.
Then remove the four nuts that hold the cylinder down and pull it off from the bottom end.
This is as good as any time to check the rod bearing for play. Side to side is fine. Up and down is bad.
Next step is to remove the right side cover.
Then remove the clutch spring retainer
Then the clutch nut
Pull the clutch assembly out and the primary gears then you will have this
Remove the kicker assembly and idler gear along with the shifter shaft. (You will need to at this point if you haven't already, remove the shifter.)
Now flip the case over and remove the flywheel cover
Remove the flywheel nut and use a puller to remove the flywheel
Remove the coil plate and the key way
Now remove all the bolts from the left side of the case and install your case splitter
You will see that as you split the cases the crank end will want to come first. I use a soft hammer to tap the cases so it pulls evenly.
After you have the cases split then it is time to remove the transmission gears. Start by removing the two shift fork guide rails
than the transmission shafts and gears should lift out with the shift forks still in place
Now you have a just about empty case half with the crank still stuck in there. It won't hurt to remove the shift drum at this point
I used a press to push the crank out
The bearings stayed in the case on both halfs so I just pressed them out using pine 2x4's as press plates so I didn't hurt the face of the case halves
now is the time to install the crank seals. I used the press again but this could be done with a hammer and the right sized driver
Once you have both crank seals installed You need to figure out how you are going to install the crank bearings.
Option 1 Warm the case half and freeze the bearings
Option 2 Use the press
After you have the bearings in the case it is time to install the crank into the right case half. I like to use the freeze and heat for this. Put the crank in the freezer for as long as you can. A few hours will work just fine. If you use a heat gun to warm up the bearing in the right case half it will help but be careful not to melt the seal. If all goes as planed than the crank will drop right in with a thunk as it bottoms out in the bearing.
Now reinstall the transmission in the case along with the shift drum
Install the shift forks and guide rails
Use a good case sealer
I bought, and am happy with the Tusk crank puller to do the next step. You might get by using heat and freeze or pulling with the case bolts but this crank puller works great!
Keep an eye on how things are going together while you pull the case halfs together. You want them to go as even as possible
Now that the cases are back together it is time to put all the bolts back in and tighten them. Then flip the bottom end back over and reassemble the clutch side
Once you get to the point of having the basket back on and the primary gears in place it is time to torque them down. What I have found to work well is to fold up a shop rag and jam the gears with it
I have found that with the rag in the gears and flat washers on the clutch springs you can tighten the clutch retaining nut easily.
Assemble the rest of the clutch
The next step is to install the right side cover. I find it easier to place the KIPS governor in the cover and hold it in place with the KIPS actuator shaft
Now back to the other side. Reinstall the coils and flywheel. We will get to tightening the nut later
Now clean up the cylinder and head and reinstall
Hold the shaft and tighten the left hand thread nut
Now it seems I don't have a picture for the tightening of the flywheel but you can either use a piston stopper, put it in gear and bind the chain, or before you reinstall the right side cover you can hold the nut on the right side of the crank and torque the flywheel nut.
While you have everything apart it is a good idea to clean and inspect every part that you touch and replace everything that needs replacing.
I hope this can help some one in the future. As of now I am done for the night I will probably make a few edits tomorrow but you get the idea.