Need to pull crank bearing off

[Tecate250]

All thats holding me up from assembling the tecate motor is to pull the crank bearing off the water pump side of the crank. I am pressed for cash and I was hopping to have my bike running in the fall. I was told to put the case in the oven and the bearings in the freezer to re assemble? I have had crank cases apart but never replaces bearings let alone crank bearings.

[jason 32]

youll more than likely need to heat the berring to get it off the crank- some are pressed on the cranks---- some are pressed in the cases
dont heat the crank- just the berring it will slide off then:Bounce

berrings-
i just tap them in- make sure to get them in all the way-- i have used a oven 1 time after that i said screw it -i still had to tap the berring in even when it was hot---- freezer - dont bother-
just clean the berring race polishin it wouldn't hurt either,and check the oil hole in the case at the top of the berring!!! make sure its clean ,and check after the seal,and berring is installed, tap them in square i havent had problems doing it that way
soak the case in boiling hot water-instead of the (oven thing) you will need good gloves

[Tecate250]

Wow thaks alot. I hope This will get things moving again.

[tecat-z]

There is a tool to remedy this common delima. And it is most definately not jamming screwdrivers or chistles between the crank web and the backside of the bearing hoping to pry it off. Many times the grip of the crank on the bearing is greater than the tight tolerance between the outside of the race and the bearing saddle in the case half. All shops have this tool and it is simply a two piece tool with bolts on the outside to squeeze the two halves together. The one side is flat all the way up with the other side beveled to gently force itself between the bearing and lobe. When the bolts are evenly tightened it forces the two halves together and pushes the bearing off like butter. Many times the stator side is the worst since it is succeptable to moisture rusting the end of the crank between the main seal and behind the balancer taper causing the bearing to sieze. This is a very cheap job for a shop to do. Many times it can be done while you wait.

[Tecate250]

should I pay the little amount for this job?

[jason 32]

so you dont have a torch set?-"not sure if a propain on will work- i would wrather use a lil heat- slip right off,
"dont "quench"-( dip in water to cool,it will weakin the part )-- any of your heated up parts
clean the crank with some polishing cloth or 400-600 sand paper

[Tecate250]

I have propane just a little scared to heat it up thats all.
So just heat the bearing?

[maggiesboy]

yes, heat the bearing only. A propane or MAPP gas torch will do the trick.

[Tecate250]

Id love to know how much money this site has saved people like me, who are not mechanics but can rebuild motors, and all.
From spare parts to helpfull info.

I thank you.

[jason 32]

yea you wont hurt it believe me lol, ive had a couple cherry red it didnt hurt

[Tecate250]

Tried unsuccesfuly last night to get the bearing off.
But I didnt get it red hot yet. That and I forgot about the mmm 2 stroke residew left on the crank and started to smoke out the work shop.
Once its red hot then what?
Gently pry it off?

[jason 32]

lolol should have washed with some thinner,and dried ittap a screwdriver between it and the fly weight as you heat it- just heat the inner race

[InPiEcEs]

Yup, you want to heat the part around the crank.
When you are heating the bearing, what you are doing is expanding it so it loosens up on the crank a bit.
Heat makes the hole in the bearing open up a few thousandths of an inch, and with enough heat, they sometimes just slide right off.
Once they start cooling off, they go back to their natural size, and bind up tight on the crank.
If you are having trouble getting it off, you may need more heat than your torch has to offer.
You could also bring the crank to any auto machine shop, if you don't like the dealer, and can't get it yourself. It won't cost much either way, though.

[Tecate250]

I have a straight pipe propane tourch and it can make things pretty hot.
And this process will not hurt the crank? what about reinstaling the bearings? Should they be put in the case or on the crank? do any of you guys put a little silicone on the seal iner side? I have not done this but I have seen this done befor. This was to seal the seal to the case???

[tecat-z]

Ok, heating the bearing red hot only transfers heat to the end of the crank since steel is a conductor, right. So you are weakening the the end of the crank where vibration is at its most fierce, at the outsides. You want problems, break a crank at 8000 rpm WOT. Yeah, you found them. Dont jam, pry, or heat. Spend a couple bucks now or trash your engine later. I can assure you it will grenade the whole engine if it breaks. Not to mention the runout issues you have already started through extreme hot cold cycling.

[jason 32]

tecat-z ----i havent hurt one yet--- it will not "grenade" it-- now if you "quench it in water" too cool it off it will crystalize the metal and break easier

[tecat-z]

------------:crazy: -----------

[Tecate250]

Im going to take it to a atv shop to get the bearing pulled. While im there im going to pick up my xmas gift,break pads.:w00t: First bike that is going to have breaks. 1st one out of 40:crazy:

[jason 32]

:crazy: :rolleyes: ---

:lol:-- well atleast it will get done-- merry christmas-:w00t: