- Nov 5, 2002
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Is a case spliter need to splict the cases on a dirtbike?
Case Spliter
- Thread starter KrackerRacin
- Start date
I really appreciate this thread. I always thought the cases were really stuck together....
How about assembly??? Do the case bolts have a hard time closing the cases?
I am slowly working up the level of guts to do this. I think 6 months and a 12 pack of rootbeer (to entice studboy to help) should do the trick!
This is the only part of a motorcycle I have yet to tak eapart.
How about assembly??? Do the case bolts have a hard time closing the cases?
I am slowly working up the level of guts to do this. I think 6 months and a 12 pack of rootbeer (to entice studboy to help) should do the trick!
This is the only part of a motorcycle I have yet to tak eapart.
jmics19067
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- Jan 22, 2002
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Using a rubber mallet on the end of the crank can get the cases apart but I wouldn't do it unless you are going to be rebuilding the crank. If you have a steering wheel /balancer puller for cars you can easily make an excellent puller.
lay your ignition cover on a piece of 1/4 steel , mark and drill the mounting holes, drill a big hole in the middle on the crank center line. I thread the flywheel nut back onto the crank. Sandwich the steering wheel puller between the crank and the plate you just made with some long screws/bolts. I then back off the flywheel nut so the puller is hitting both the nut and the crank. Make sure your home made plate screws are snug and the plate is even with cover mounting area.
This may be overkill compared to using the two mounting screws for your ignition plate but you dont have to worry about the puller kicking off to the side either damaging the end of the crank or pulling the threads in the timing plate screw holes. With a wrench in one hand and a rubber mallet in the other tighten the puller screw and tap the countershaft.
Once you make the plate it almost works itself off . I used to do the " try and hold the case up and whack the crank with a mallet " until I had a stubborn one. I will never go back to it again with the possiblity of your transmission parts exploding from the case all of a sudden letting loose, bouncing off the bench and hitting the floor.
lay your ignition cover on a piece of 1/4 steel , mark and drill the mounting holes, drill a big hole in the middle on the crank center line. I thread the flywheel nut back onto the crank. Sandwich the steering wheel puller between the crank and the plate you just made with some long screws/bolts. I then back off the flywheel nut so the puller is hitting both the nut and the crank. Make sure your home made plate screws are snug and the plate is even with cover mounting area.
This may be overkill compared to using the two mounting screws for your ignition plate but you dont have to worry about the puller kicking off to the side either damaging the end of the crank or pulling the threads in the timing plate screw holes. With a wrench in one hand and a rubber mallet in the other tighten the puller screw and tap the countershaft.
Once you make the plate it almost works itself off . I used to do the " try and hold the case up and whack the crank with a mallet " until I had a stubborn one. I will never go back to it again with the possiblity of your transmission parts exploding from the case all of a sudden letting loose, bouncing off the bench and hitting the floor.
jmics19067
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- Jan 22, 2002
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Reesknight
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- Oct 31, 2002
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According to the manual I had at the time, it said NOT to use the case bolts to pull it back together. It also said that the halves should fit together easily :silly: . I used a small hydrolic press to push the left case onto the crank spindle until it 'popped'. Worked great except I hadn't realized that I had kinked my gasket and didn't know it until I had put the ENTIRE BIKE BACK TOGETHER! I poured in oil and it came straight out the bottom :( . I had to re-do the entire process. :debil: And I would have never gotten the cases apart without a spliter.
jmics19067
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- Jan 22, 2002
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ugh sorry aboutthe sloppy posting but anywho,
This is a trick I learned from a guy who used to own a Bultaco dealership. If anybody remembers Buls well there apparently was a recall problem with the connecting rod set to tight and this guy rebuilt a lot of cranks under warranty<?>.
any how make sure everything is clean, cases soap and water clean. if you dissassemble the transmision put a light coat of STP or thick motor oil on the shafts before you assemble the gears. Put the crank,new bearings, and transmision in the freezer.
With all the bearing retainers removed from the bearings you want to replace, place the cases in the oven and cook them at 400 degrees farenhiet for an hour. With welding glose or good oven mitts pick up the cases most of the time the bearings will be left in the oven , if not one good slapping down of the case against some hard wood will knock them out. A quick wipe of a clean rag behind the old bearings and make sure there are no splinters of the wood stuck in the dowels. Drop your frozen bearings into the respective bores of the hot case with a slight tap of a hammer handle to make sure the bearings are seated and install any bearing retainers with blue loctite on the screws. Install your frozen crank and transmision< the light coating of STP is real sticky now help holding the gears on the shafts> in the right side case. Put on your gasket or gasket sealer. Line up the right side case with the crank and transmision shafts and drop it on. If there is less of a 1/4 gap around the case you should be ok to tighten up the case screws<in a criss cross pattern> to snug it down evenly and tight. I use a brass or wooden punch and just give a slight tap around all the bearing bores of the case and a slight tap with a rubber mallet all the way around the crankcase seam. Make sure your shirt front or gloves didn't get pinched in the seam, you will look kinda sillly walking to the tool box with an engine hanging off your belly looking for that case splitter you made earlier.
Assemble your shifter and make sure you have all the gears and spin the crank <it should always return to top dead center without a piston on it >making sure everything spins free and smoothly. When everything is cool double check screws tight and smoothness of rotating parts.
If you spend your time making sure everything is clean and organized before you start, it is truly simple and easy once you done a one or two. The guy I used to watch could have Bultaco bottom end from oven to complete in 20 minutes 1/2 hour.This I know works extremely well for 82 and 88 RMs <even though they tell you to build it in the left case for the shifter detent spring but a pair of long needle nose pliers takes care of that> and a 94 yz250. I am pretty sure it would work for just about anybike unless the heat of the crankcases will melt the inboard mounted seals<kawasakis I think>.
This is a trick I learned from a guy who used to own a Bultaco dealership. If anybody remembers Buls well there apparently was a recall problem with the connecting rod set to tight and this guy rebuilt a lot of cranks under warranty<?>.
any how make sure everything is clean, cases soap and water clean. if you dissassemble the transmision put a light coat of STP or thick motor oil on the shafts before you assemble the gears. Put the crank,new bearings, and transmision in the freezer.
With all the bearing retainers removed from the bearings you want to replace, place the cases in the oven and cook them at 400 degrees farenhiet for an hour. With welding glose or good oven mitts pick up the cases most of the time the bearings will be left in the oven , if not one good slapping down of the case against some hard wood will knock them out. A quick wipe of a clean rag behind the old bearings and make sure there are no splinters of the wood stuck in the dowels. Drop your frozen bearings into the respective bores of the hot case with a slight tap of a hammer handle to make sure the bearings are seated and install any bearing retainers with blue loctite on the screws. Install your frozen crank and transmision< the light coating of STP is real sticky now help holding the gears on the shafts> in the right side case. Put on your gasket or gasket sealer. Line up the right side case with the crank and transmision shafts and drop it on. If there is less of a 1/4 gap around the case you should be ok to tighten up the case screws<in a criss cross pattern> to snug it down evenly and tight. I use a brass or wooden punch and just give a slight tap around all the bearing bores of the case and a slight tap with a rubber mallet all the way around the crankcase seam. Make sure your shirt front or gloves didn't get pinched in the seam, you will look kinda sillly walking to the tool box with an engine hanging off your belly looking for that case splitter you made earlier.
Assemble your shifter and make sure you have all the gears and spin the crank <it should always return to top dead center without a piston on it >making sure everything spins free and smoothly. When everything is cool double check screws tight and smoothness of rotating parts.
If you spend your time making sure everything is clean and organized before you start, it is truly simple and easy once you done a one or two. The guy I used to watch could have Bultaco bottom end from oven to complete in 20 minutes 1/2 hour.This I know works extremely well for 82 and 88 RMs <even though they tell you to build it in the left case for the shifter detent spring but a pair of long needle nose pliers takes care of that> and a 94 yz250. I am pretty sure it would work for just about anybike unless the heat of the crankcases will melt the inboard mounted seals<kawasakis I think>.
The only thing I would be afraid of is I have heard Aluminum's molecular structure starts getting altered starting at 350 degrees F. I remember a few years ago that Dive Shops would refuse to fill any freshly painted tanks (I had this happen in the Keys to me!).. It seems that an enterprising dude painted his tank, baked it in the oven at 400 degrees, and when it was filled, it exploded. I have seen pictures of an exploding Scuba Tank completely removing the back of a car..
So, I'd check on the heat deal and heat them no higher than 300 degress or so..
jmics19067
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- Jan 22, 2002
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good point , although I have never had any problems. I am not a metalurgist by any means and sometimes I do anneal things by bakeing at 400 and sowly letting it cool.
Although I think that there might be a difference between a pressure tank being made from rolled /stamped plate welded together and is probably heat treated compared to a casting of an engine case. I pretty sure your engine doesn't recieve any great loss of integrity for its intended purposes compared to a tank being pressurized to 2000psi<?>.
Any metalurgists out there recommend a safe temp.
Although I think that there might be a difference between a pressure tank being made from rolled /stamped plate welded together and is probably heat treated compared to a casting of an engine case. I pretty sure your engine doesn't recieve any great loss of integrity for its intended purposes compared to a tank being pressurized to 2000psi<?>.
Any metalurgists out there recommend a safe temp.
darringer
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- Dec 2, 2001
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I never hit the crank to separate the cases. There is usually somewhere on 1 half to lightly rap the case to start to separate it. I only heated the cases to about 220- 230 deg. F. I've never had trouble removing bearings in this manner. As far as putting the cases back together, do not use the case bolts to pull them together. They should go back together completely rather easily, provided everything is where it should be.
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