splitting cases 1980 KTM 175

[skiracer]

I need to split the cases on a 1980 KTM 175. I am either looking to rent or borrow the tools needed, or someone in the Northeast that is interested in doing the job.  I need to re-set the kickstarter spring.  I can't find any dealers within a 100 miles of my area that will do the job........Anybody interested?  I would appreciate the help.  I can be reached at; [email protected]

[Big Mac]

Skiracer, If the '80 motor is same as '72-'78 175 motors, only special tool you'll need is a flywheel puller, about $25 and maybe a torque wrench to get everything right when you re-assemble. Much easier to split these KTM cases than you'd imagine. A manual helps too, but not even that necessary, just work from the right side in.

Good luck. Mac

[G Ellis]

skiracer.. I can split the cases if you need me to. I live in Illinois East central part of the state. I also have some case splitters for sale or you can use one. If you split the cases,I would replace the bearings,check the gears and clutch when you have it apart. You can email me at [email protected]  Hope this will help. G Ellis:D:D

[skiracer]

Thanks for the input!  I have the service manual for the KTM's in general.  I have a couple of questions: Do I have to take the clutch hub off? The reason I ask, there are notes further in the dismantling section that says "if the clutch is not removed."  If special tools are not needed, how do you set the new bearings for the crank?  If I have it apart I might as well replace them.  They also mention (3) bullet shaped  pieces to help line up the case with the gears when you put it together.  Are they needed? AND, they talk about heating the cases to get the old bearing out. So, how hot to you cook them, raw, medium, or well done? 125 degrees?

[John Ehrhart]

You don't need to remove the clutch or disassemble it at all to split the cases.
I would, in addition to replacing the mains, while you are in there, also replace the crank seal.
I don't have my manual with me, but I thought it gave a temperature. I wasn't too concerned about it though: I let a local shop handle the bearing replacement. It requires more ability than I possess to get the old bearings out, and to put the crank back in the left side.

John

[skiracer]

John, thanks for the info.  Yes, I am planning on replacing the crank seal while I have it apart.  And yes, the manual give a temp of 165 degrees.  I have found the local shops not too receptive to working on this "old junk" as they put it, so I am not sure if anyone will press the bearings for me.  Thanks for your input, I appreciate it.  James

quote:Originally posted by John Ehrhart

You don't need to remove the clutch or disassemble it at all to split the cases.
I would, in addition to replacing the mains, while you are in there, also replace the crank seal.
I don't have my manual with me, but I thought it gave a temperature. I wasn't too concerned about it though: I let a local shop handle the bearing replacement. It requires more ability than I possess to get the old bearings out, and to put the crank back in the left side.

John

[skiracer]

Hi Mac,

Yes, for the most part they are the same.  One difference, is that they put a bolt through the cases on the bottom as a motor mount which the mid 70's bikes did not have.  I have a 76 250 MC5, which has the braces on top of the motors that go up to the frame.  The 1980 doesn't have the braces anymore.  Otherwise, the outside of the motors look the same, I assume (dangerous word!) that the inside is not too bad.  Thanks for the input!  

quote:Originally posted by Big Mac

Skiracer, If the '80 motor is same as '72-'78 175 motors, only special tool you'll need is a flywheel puller, about $25 and maybe a torque wrench to get everything right when you re-assemble. Much easier to split these KTM cases than you'd imagine. A manual helps too, but not even that necessary, just work from the right side in.

Good luck. Mac

[Big Mac]

Assuming no significant changes to the guts of a +'79 motor, if it were mine and it felt pretty tight and not all hammered from too many hours, I'd simply split cases, correct your kicker spring problems, inspect all the best you can (feel for up-down end slop on the crank ends, chips in gear teeth, rough-rolling tranny bearings, bent shift parts, up-down movement in connecting rod) and if all seems right, re-assemble and go.

It's really very easy to split, reinspect and reassemble KTM motors, easier than any I've ever worked on. Getting the pipe off and the motor out of the frame is the hard part. If you're going the whole bottom end rebuild route, unless you have a press and experience, I would suggest you leave the crank separation/big end bearing replacemtn to an expert, and have someone help you at least get the reassembled crank pressed into the left case half. The rest is pretty simple.

For the repair-only approach, as an example, Thom Green and I split cases on a '78 400 motor, replaced a broken shift arm with a good used one, felt the tranny bearings for roughness (replaced one with a smooth-rolling used one out of a parts motor on hand), got a good new center gasket and had all back together in a couple hours, with a flywheel puller, a $40 electric impact wrench and a modest toolbox.

The clutch hub doesn't need to come out unless you're to replace the bearing that shaft rides on---no special tools needed, the cheap impact wrench makes the large nuts very easy if you got that route. The shift fork shafts will go back through the case pretty easy with just some jiggling through the holes with a small phillips, or you can carve up some small dowels out of same size wood if you prefer.

The main bearings are 3-piece (at least they were through '79), free floaters...the key to ease of case-splitting for KTM motors. To get to the innards, the right side case pulls off easy--nothings pressed in at all. All the bearings are oversize compared to Asian brands, so they wear well in comparison. I've tried the heated cases method, but seems that a rubber mallet and right-sized socket or such that catches the outside bearing races will knock the tranny bearings out of room-temperature-warm cases without much trouble. I've bought an assortment of larger galvanized pipe fittings in different diameters which are cheap and work on bigger bearings. A heat gun (or hair dryer?)blast warms things and helps loosen up a bit if needed.

If the replacement bearings are straight and don't get cocked, I've found they press in without fighting much in the same manner---gentle persuasion on the outside race with a socket and mallet, or better yet, using a socket and my bench vise to press in more gently.

Haven't had a post-replacement failure yet. Getting the crank rebuilt and in and out of the left side case is the only part that's a bit challenging. The rest you can do with a decent toolbox. Go for it and advise how it works out.

Mac

[skiracer]

Thanks Mac!  I have used the socket and bench vise many years ago, and it worked well, just as long as the bearing is started correctly.  One more question: Does the crank have to be pressed onto the bearing when I re-assemble, or does it just slide on by itself, or with a few taps of a rubber hammer.  Thanks for the support and advise.  I have a good selection of hand tools. So that won't be a problem at all. I will call Al B. tomorrow and order the gasket, and I guess I am good to go.  I have two 250 spare motors that I will probally do next.  I will let you know how I make out!

quote:Originally posted by Big Mac

Assuming no significant changes to the guts of a +'79 motor, if it were mine and it felt pretty tight and not all hammered from too many hours, I'd simply split cases, correct your kicker spring problems, inspect all the best you can (feel for up-down end slop on the crank ends, chips in gear teeth, rough-rolling tranny bearings, bent shift parts, up-down movement in connecting rod) and if all seems right, re-assemble and go.

It's really very easy to split, reinspect and reassemble KTM motors, easier than any I've ever worked on. Getting the pipe off and the motor out of the frame is the hard part. If you're going the whole bottom end rebuild route, unless you have a press and experience, I would suggest you leave the crank separation/big end bearing replacemtn to an expert, and have someone help you at least get the reassembled crank pressed into the left case half. The rest is pretty simple.

For the repair-only approach, as an example, Thom Green and I split cases on a '78 400 motor, replaced a broken shift arm with a good used one, felt the tranny bearings for roughness (replaced one with a smooth-rolling used one out of a parts motor on hand), got a good new center gasket and had all back together in a couple hours, with a flywheel puller, a $40 electric impact wrench and a modest toolbox.

The clutch hub doesn't need to come out unless you're to replace the bearing that shaft rides on---no special tools needed, the cheap impact wrench makes the large nuts very easy if you got that route. The shift fork shafts will go back through the case pretty easy with just some jiggling through the holes with a small phillips, or you can carve up some small dowels out of same size wood if you prefer.

The main bearings are 3-piece (at least they were through '79), free floaters...the key to ease of case-splitting for KTM motors. To get to the innards, the right side case pulls off easy--nothings pressed in at all. All the bearings are oversize compared to Asian brands, so they wear well in comparison. I've tried the heated cases method, but seems that a rubber mallet and right-sized socket or such that catches the outside bearing races will knock the tranny bearings out of room-temperature-warm cases without much trouble. I've bought an assortment of larger galvanized pipe fittings in different diameters which are cheap and work on bigger bearings. A heat gun (or hair dryer?)blast warms things and helps loosen up a bit if needed.

If the replacement bearings are straight and don't get cocked, I've found they press in without fighting much in the same manner---gentle persuasion on the outside race with a socket and mallet, or better yet, using a socket and my bench vise to press in more gently.

Haven't had a post-replacement failure yet. Getting the crank rebuilt and in and out of the left side case is the only part that's a bit challenging. The rest you can do with a decent toolbox. Go for it and advise how it works out.

Mac

[Big Mac]

Ski,

The crank has to be pressed (or pulled) into the left case half outside bearing. There's the 3-piece (race on crank, free-floater bearing ring, race in case) main bearings on either side of the crank, but outside of the case race on the left, there's a thrust washer, oil seal, then the one piece bearing that sits behind the pinion gear.

This bearing is a press fit on the crank and into the case, so can be tricky. It knocks out of the case to the outside, after you press or gently whack the crank through to the inside in order to disassemble. On re-assembly, you have to take care to not put too much stess on the crank assembly or you run the risk of knocking the crank half webs out of alignment. Others can possibly advise better, but I'm aware of two methods to tackle this, both done or described by others, so this is theoretical here:

"Kip Kern" pull method-- Replace the seal and get the thrust washer in the case right, then press in this outer bearing from the outside. Then with the main bearing on the inner race, slide the tapered crank in as far as it will go by hand, with threaded end sticking through to the outside. Then gently thread on the pinion gear nut on top of varying thickness washers/spacers to slowly work the crank in through the bearing until the main is pulled up acceptably tight in the races.

"Charlie Brown" push method-- I respect the skill and experience of this talented machinist, so took my last KTM motor to him to rebuild the crank and press it into the left case bearing for me. He puts the outer bearing in the left case half, puts it up on his press with a spacer on the table to push in against the inner race. Then he drops in the crank assembly. Before he starts pressing, he installs 2-3 steel shim wedges between the crank halves around the radius of the crank, the same width as at the crank pin. He then presses away to seat the crank in place, pulls out the shims and he's done. Seemed pretty barbaric to me when he explained it, but it got the job done just fine and my motor works just like it should.

There, more than you ever wanted to know, I'm sure. Good luck. Mac

[DKWRACER]

Great advice from Big Mac, removing/replacing the cranks from the LH side can be the biggest challenge, but can be done. While away at the innards, if you have a v-block, you can ck the squareness of the shift forks, also pay attention to the "tits" on the ends of each shift fork, poorly maintaind motors exibit a wear pattern on one side of the tits, causing shift problems in one direction, can also look very closely at the final detent position of the drum for indications of wear....Bearing replacement ease: cool the new bearings for some time in the freezer, this will help in insertion. Have a look at the dogs or mating surfaces of the gears, you might find rounded edges on 1/2/3 gearsets, also, some of the gears that do not move are captured by jesus clips, the edges can become worn causing wobble of respective gears/shafts......
Keep us informed!
Tom Brosius [8D]

[skiracer]

Thanks Mac!  NO, the more info the better!  I will let you know how things turn out.  James

quote:Originally posted by Big Mac

Ski,

The crank has to be pressed (or pulled) into the left case half outside bearing. There's the 3-piece (race on crank, free-floater bearing ring, race in case) main bearings on either side of the crank, but outside of the case race on the left, there's a thrust washer, oil seal, then the one piece bearing that sits behind the pinion gear.

This bearing is a press fit on the crank and into the case, so can be tricky. It knocks out of the case to the outside, after you press or gently whack the crank through to the inside in order to disassemble. On re-assembly, you have to take care to not put too much stess on the crank assembly or you run the risk of knocking the crank half webs out of alignment. Others can possibly advise better, but I'm aware of two methods to tackle this, both done or described by others, so this is theoretical here:

"Kip Kern" pull method-- Replace the seal and get the thrust washer in the case right, then press in this outer bearing from the outside. Then with the main bearing on the inner race, slide the tapered crank in as far as it will go by hand, with threaded end sticking through to the outside. Then gently thread on the pinion gear nut on top of varying thickness washers/spacers to slowly work the crank in through the bearing until the main is pulled up acceptably tight in the races.

"Charlie Brown" push method-- I respect the skill and experience of this talented machinist, so took my last KTM motor to him to rebuild the crank and press it into the left case bearing for me. He puts the outer bearing in the left case half, puts it up on his press with a spacer on the table to push in against the inner race. Then he drops in the crank assembly. Before he starts pressing, he installs 2-3 steel shim wedges between the crank halves around the radius of the crank, the same width as at the crank pin. He then presses away to seat the crank in place, pulls out the shims and he's done. Seemed pretty barbaric to me when he explained it, but it got the job done just fine and my motor works just like it should.

There, more than you ever wanted to know, I'm sure. Good luck. Mac

[skiracer]

Thanks Tom!  I will let you know the outcome.  James

quote:Originally posted by DKWRACER

Great advice from Big Mac, removing/replacing the cranks from the LH side can be the biggest challenge, but can be done. While away at the innards, if you have a v-block, you can ck the squareness of the shift forks, also pay attention to the "tits" on the ends of each shift fork, poorly maintaind motors exibit a wear pattern on one side of the tits, causing shift problems in one direction, can also look very closely at the final detent position of the drum for indications of wear....Bearing replacement ease: cool the new bearings for some time in the freezer, this will help in insertion. Have a look at the dogs or mating surfaces of the gears, you might find rounded edges on 1/2/3 gearsets, also, some of the gears that do not move are captured by jesus clips, the edges can become worn causing wobble of respective gears/shafts......
Keep us informed!
Tom Brosius [8D]