125 right side main bearing removal

[Doc]

I'm after a little info on a KTM125 mx'er. It has twin leader drum brakes front and rear, water cooled, single shock, conventional forks and square frame mounted number plates. rumor has it '84 but I'd have thought a disc up front for sure by then. 82?? I'll try and get a pic but it's a little difficult since the bike is quite apart at present. The motor I again assume is a type 501 cause it looks just like it in the pictures but for the life of me the right main brg does not want to let the crank slide out easily  I don't want to force anything and being a sealed bearing I don't want to heat anything..am I not holding my tongue right or something..it's been apart before as I can see the tell tale marks of this. Do I just slip a piece of suitable tube over the impeller end and press it out or is heat needed or should I just go take a pill then a nap and it'll all be crystal clear when I awaken?  many thanks in advance.

[TonyB]

Doc heat it up even the 495 manual says so. All my Yamaha tear downs have been as easy as ..with heat. Don't play though, you need to heat thouroughly through at 120C to 130C. I left my cases in the oven at 130 for an hour once (got talkin to my neighbour over a beer and forgot the damn thing) I raced back thinking it would be a blob of alloy on the bottom of the oven but it was still good and the bearings just slid out.

[Doc]

Thanks Tony..I don't like the look of it all so I might pass this part of the operation to someone with a little more expertise with said critters and their crank bearings. (not to mention I don't have an oven big enough I could use..not even on the sly ) the rest is easy stuff but I do have another question for anyone in the know. How thick is the centre case gasket? The one I removed was less than 0.40 with lots of that aviation gasket goo stuff applied..yuck..don't even like the smell of the stuff and it does untold damage when it gets in places it shouldn't..I think that is in fact what actually may have killed this particular little Katoom

[oz555ktm]

Ring Me .

It take me to long to anser on this form as I cant spell for Shit .

So ring me on 0411 598 818

up to 9.30 pm .

Dennis

[Doc]

okay, new bearings throughout, the right bearings now sorted too and I was about to reassemble but alas I now have hit another slow up issue the crank slots easily into the left 'wide' type roller bearing but tryng to slip the crank into the conventional deep groove 6205 roller bearing on the otherside is woeful! I froze the crank and had the cases baking in the sun all day and I would have been lucky to get 2mm of the crank into the bearing and it stops solid. The bearing is a good quality Nachi and I have tried another (correct size according to the parts listings) but it's a heck of an interference fit if this is what it's supposed to be. Is it normal for the crank to prove a royal bastard to get into the right main or am I holding my tongue wrong or perhaps not muttering the correct magic words!! It just doesn't feel right and I ain't about to force it thanks for any help in advance

[PEZBerq]

Husky cranks are also a press fit in the bearings .  I made up a puller to do the job - essentially a steel tube that slides over the crank shaft and allows you to pull the crank through the tube by using the thread on the end of the crank.  The force is applied via the tube to the inner race of the crank bearing and pulls the crank through the bearing without loading the bearing in any way.  Some people use a ginormus stack of washers instead of a tube.  Others claim to heat the crankcases in the oven and freeze the crank in the freezer.  I decided that was way to messy and didnt fancy water condensing on my crank bearings or buring myself on hot crankcases!   Good luck.

[Doc]

mmmm..just got some detailed info today and yup, it says I have to heat the cases to 150°C and fit the crank 'grmbl grmbl' Now I don't mind a bit of heat but I like your pipe/nut and pulling the crank through the bearing idea much better PEZBerq. Thanks for the tip

hang on! the manual still doesn;t tell me how to get the bearing onto the crank only how to get the crank with bearing into the case..bloody Austrians!! 

[ozktm]

i have two of these bikes,
i think it's a matter of heating the case with bearing in it to 150, have the crank frozen and it should get most of the way through allowing you to use the thread and nut to pull it through. that's from memory. Should just fall on.
i do have the workshop manual for that motor somewhere, but have to go looking.

Adrian

[090]

Im glad i palmed this onto you Doc !

[Doc]

$@#&%*!! thanks Brad  Adrian, not being a smart arse but I really really loved the idea of using the threaded part with a nut and washers to pull it through the bearing only for a wee problem, the end of the crank in question has a waterpump worm drive and not a thread to be seen bugger!..hence it's in the shop..they break it they fix it!  I also had some manual scans supplied to me by Cyclone Sully from Emerald and they state pretty much the same as you..heat it and freeze and it'll go together. But, the bearing is a sealed type so what's the go, do I still heat it?? I tried the frozen crank and sun heated cases and bearing and managed about 2mm in the bearing and she locks tight. I simply don't want to wreck anything..not knocking Katooms but give me jap bikes to work on anyday..never had this trouble before

[PEZBerq]

Here the tool I made up. 

[PEZBerq]

In action.

[PEZBerq]

Take 2 

[Doc]

that is a lovely tool PEZberq..do you make replica's?

the idea would work so wonderfully well if only there was a thread to use it on like most others. I been thinking too (yes it hurt!)but, I suppose in use, the motor and sealed bearings can and do sometimes get quite hot so 150° in the oven would probably be quite a safe temp. A little late to try now I guess but maybe I should have been a little braver incidently, what's the bottom end from? I can't say I recognize it.

[PEZBerq]

Hi Doc
Its a Husky 430 bottom end. 
I dont have the gear to make the tool.  I designed it and got a local machine shop to knock it up.  All you need is a lathe and a welder though.  The workshop took so long to do it they didnt charge me . Lucky I was not in a hurry. 
If anyone is interested I can email a sketch.  It is a one man operation to use but someone to help makes it a hell of a lot easier .....unless you have three hands