Definative main bearing thread

[bushmechanic]

dunno Tourist

there was some speculation that too much axial play can let the crank slap around too much and crack the inner race lip.

ive never seen that in my stuff even with approx 1mm end float

in other engines it can't be done because of the e starter etc

IMHO there is no need for more than 1mm most of the time.

 

[pdbarry]

new nearing too tight to determine axial clearance

Hi.

I am rebuilding a 2007 KTM 250 XCF and an having trouble measuring the axial clearance.

I bought new crank and main bearings from Hot Rods on the advice of many riding friends. It all seems good ... except that the new inner races are so tight in the new roller bearings that there is essentially no axial play. Thi crank has the inner races pressed onto the crank. i used the actual KTM tools to do that part.

There may actually be some axial play once things heat up- but it's impossible to tell because you can't move the crank "sideways". In fact it has to be "persuaded" out of the ignition side of the case/bearing with a mallet.

I'm tempted to take some fine emery paper to the inner race to allow a looser fit.

Any ideas? Is this normal for new bearings?

Thanks guys.

 

[bushmechanic]

yes that works as long as the outer race and cage don't get too close to the crank

some of the berg engines converted to roller from ball dont have enough room for any axial play, most of the time one of the crank case halves is machined out deeper, its an easy job in a mill.

you should ask on ktmtalk rfs section as to what axial play is ok for your engine, it might not need much at all.

 

[Borgschulze]

So I finally received some parts.

I'm just working on replacing my mains at the moment.

The Left side came off no problem first try..

The Right side, which is the one that is totally screwed... doesn't want to come off, and is an NTN race that had been run in an SKF bearing for some bizarre reason.

Are the NTN races tighter fitting? Or did I mess up somehow?

I put the whole crank in the freezer, more than 12 hours before attempting to use my tool I made.

Started heating the tool with a propane torch, grabbed the crank from the freezer, held with with my legs, since I don't have a vice at my new house... continued heating the tool just in case, less than 1 minute out of the freezer, try to move the NTN race, no go... probably 5 minutes after the crank came out of the freezer, had the tool heated up nice and hot again... drop it on the SKF race, squeeze, and not even 15 seconds later, I had the SKF race off.

The NTN race absorbed the heat from the tool, and transferred it to the crank, enough that I couldn't touch the area around the race comfortably. So heat definitely transferred... should I just cut a slot in the race, and try to break it open? Going to try again later tonight with the tool I made.

Also, how do you guys get the ignition side main bearing out of the case? I was thinking about grinding an old race down so it fits through where the oil seal goes, so I can put the whole works in the oven, and try and tap it out with a drift, and not worry about the rollers falling out.

 

[Goose916]

To get the bearing out, I used an arbor press and a socket the same size as the outer race. Applied even pressure and the bearing popped right out, easy peasy. I'll send you a pic of the tool a buddy of mine had made to remove the races. That KTM race removal tool is really hit and miss for me. First time, worked like a charm. Second time, not so much.

 

[bushmechanic]

i made 2 tools slightly different

the one that works best is steel and has a funny lip to jamb in behind the inner race

its still hit an miss though

cutting almost all the way though in a spiral then hit with a fat chisel to crack the last bit open works everytime

 

[Borgschulze]

But what about the outer race and rollers?

I'm far more worried about ruining the cases than damaging the crank.

 

[bushmechanic]

oh ok just heat the cases to 150 deg C they fall out, if not out an old inner race in there and tap it .. you wont need a press if teh cases are hot

the NTN ball bearing sometimes used (KTM part) is very tight and needs a lot of mixed mechanical heat and violence

 

[Borgschulze]

This is the NTN inner race that was used in an SKF bearing.

My wife held the crank, with her hands and knees... I put the tool on the race, squeezed hard, twisted a bunch... slid the chair around the floor with her on it... and it came off...

I had 2 hands squeezing the handle together to get a good grip on it... was pulling up and whacked myself in the forehead with the handle on the other side of the tool Haha.

Just glad the "hard" part is over.

Hopefully the 150c baking session will get those bearings out of the cases.

I was thinking I could put the inner races in the oven, crank in the freezer, and hopefully the inner races will just fall onto the crank? With some pressure to make sure the spacers don't hold the race from bottoming out.

I measured between 0.38-0.42 axial play before I took the motor apart, I think the edge on the race was preventing it from moving freely?

Should I just remove the 0.2mm shim off the ignition side? I'm hoping not to have to take the new race off after it goes on, I fear my home made tool might scratch up the race... I had made the ID slightly too tight, and my lathe is over 1 hour away, so I just used a Dremel with sanding drum to bore out the ID a bit so the tool would fit a bit easier, which left the ID a bit more rough than I'd like.

I have a 0.2mm shim behind the clutch side, and 0.1mm and 0.2mm shims behind the ignition side before I removed the races.

Thanks for the help guys, don't know what I'd do without you.

 

[bushmechanic]

Should I just remove the 0.2mm shim off the ignition side?

sounds good

I was thinking I could put the inner races in the oven, crank in the freezer, and hopefully the inner races will just fall onto the crank? With some pressure to make sure the spacers don't hold the race from bottoming out.

yes you got it.

i wish i could get my wife to help with bikes

 

[Borgschulze]

She's OK with me baking engine parts in the oven too Haha.

Anyone have a sealant recommendation? For the case halves, is Permatex Ultra Black RTV suitable?

The stuff that was on the engine was grey between the case halves, and white between the head and valve cover.

 

[Palle]

Speakin of engines in The oven. I must till you that some women actually can stand it. My dad had a woman over night. When se woke up, had breakfast and putta The dishes in The dishwasher se found not only engine parts from his Trike. But allso The toiletbrush. And 5 years later they got married.

 

[Borgschulze]

Right side main installed, both new races installed on the crank.

That's the most I have accomplished on this project since I started it.

Also, the clutch side race was far more difficult install oddly enough.

The ignition side literally dropped on, had to tap the clutch side on with a hammer using the tool I made.

I got the woodruff key out of the water pump shaft, now I just need a puller to get the cam drive gear off, and I can replace the other main bearing.

 

[Borgschulze]

Thanks for the help guys!

0.6mm Axial Play.

I can only assume it will very slightly increase when there is sealant between the case halves.

I can't believe how thin the oil rings on the Wossner piston are!

Still not 100% on if I'll be keeping this bike, or selling it.

I'm at the point where I can easily make money on it.

I value the learning experience, and I have ridden this bike before I bought it, when it didn't have any issues... I know it's a bad influence on me, but at the same time, all my time I put into it!

Really love my dear Husky TE610, but the Husaberg sure is a lot more fun.

 

[bahnsy]

To the suitably knowledgeable, what should I be looking for as the root cause of the failure?

Left Side Crank Bearing
2005 FE450E
90 hrs
5800 km's
SKF Bearing

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[bushmechanic]

did you measure the crank axial play before taking it apart ?

thats the likely issue

also check crank runout and use NTN bearing on re assembly

 

[tobber11]

Good job

 

[bahnsy]

Bushy,
The axial play was 0.5 to 0.6, was hard to get an accurate measurement due to the main bearings flopping around.
What I plan to do is;
1. Replace the con rod with all new pins and bearings
2. Replace the piston & liner (obvious given the damage to the liner)
3. Replace both the SKF main bearings with NTN items.
4. Replace the counter balancer bearings (Using bearing mount solution & pin punch them "lightly"

Some questions before I re-assemble.
1. What is the ideal clearance to give the rod to the crank webs. Currently I'm going down the route of re-assembling the crank to the same width between the 1/2's using the pre-disassembly measurement that I took.
2. My bearing shop is a NTN agent, what bearing number should I ask for (I've noted that a NTN Nj206 is mentioned) or is the bearing only available from KTM?
3. Is NTN the premium bearing or should I look to Nachi or other brands.
4. Using NTN bearings (in this example), and the fact that its a 450, what axial end float should I target?
5. What run-in procedures and oil should I "ideally" use or is just get on it and ride, without giving it a hard time.

Sorry for being a pain in the arse,
Thanks, Rod

 

[bushmechanic]

G'day rod

Those ntns are special ones. And different to all the others Orangeberg has them give him a call details in my signature

I would go for Crank axial play of 0.5 to 0.6mm and rod big end axial play of 0.4 to 0.5mm

But if you talk to john about his bearings ask him.

For run in just low revs without lugging for 10 hours or so

Cheers ! bushie

 

[Taffy]

the easiest way of getting the ignition side main roller bearing out is as follows;

use a suitable bar that only just goes through the seal housing or use a 6203 gearbox bearing.

with one hand put the inner race back up and into the bearing from below and hold.

then place the shaft or 6203 in and press through with the press. the inner race keeps the rollers outwide and then they become the thing you push on.

another way to do it is to grind enough of the outside lip off the inner race that it falls through the oil seal hole. drop it into the rollers from above this time and again - just press.

and alway have enough axial float upon your rebuild and then you don't have to change from NTN or SKF or anyone or anything! axial clearance comes first so GET ENOUGH!

regards

Taffy