ATC200 crank rebuild

[Gabriel]

Well......That's my junker crank I will experiment on.
It is NOT recommended but I used an aluminum wedge and a and worked around the bearing until it popped off taking the gear (on one side) and the cam chain drive (on the other side) with it.

I'll take this crank apart first to learn what NOT to do before taking my good one apart. Then I will reassemble the old crank parts and indicate it in true first, again...to learn what NOT to do.

[shortline10]

The correct tool to remove the main crank bearings .

[Gabriel]

Well, there’s nothing to that oil pressure pad.
A roll pin, a spring and the pad itself.

I hope someone who KNOWS can explain to me EXACTLY what’s going on with it.
Not just it’s general function but it’s complete operation.
It’s not enough to fix things, I want to know how they work and why.

I took a small pin punch and lightly tapped the roll pin out of the crank. The spring is not particularly stout. No real fear of it flying across the shop.
There’s a plug that seems to be pressed into the crank. It won’t budge so I didn’t try to force it out.
I’ll post pics later when I can get to me desktop but there’s really nothing to see.

[BarnBoy]

The correct tool to remove the main crank bearings .

Ah ok. Looking at a junk crank I have it hardly looks like there is room to get the splitter in there?? Can the bearings be reinstalled by heating the bearing and freezing the crank?

[BarnBoy]

Well, there’s nothing to that oil pressure pad.
A roll pin, a spring and the pad itself.

I hope someone who KNOWS can explain to me EXACTLY what’s going on with it.
Not just it’s general function but it’s complete operation.
It’s not enough to fix things, I want to know how they work and why.

I took a small pin punch and lightly tapped the roll pin out of the crank. The spring is not particularly stout. No real fear of it flying across the shop.
There’s a plug that seems to be pressed into the crank. It won’t budge so I didn’t try to force it out.
I’ll post pics later when I can get to me desktop but there’s really nothing to see.

Interesting. Yeah would still be cool to see what it looks like. Did you find any junk inside there?

[Gabriel]

They are tight, but not ridiculous.
You could toss the crank in the freezer overnight and probably tap the bearing on fairly easy.
I cut a length of heavy wall tubing that slips over the crank to press them back on.

Getting them off with the aluminum wedge I used (bad idea and the wrong way to do it!) they were not difficult.

[fabiodriven]

Ah ok. Looking at a junk crank I have it hardly looks like there is room to get the splitter in there?? Can the bearings be reinstalled by heating the bearing and freezing the crank?

I bet they would drop right on if you did that. Shortline could probably tell you for certain. This is probably better than pressing them on I would say.

[ironchop]

...... Can the bearings be reinstalled by heating the bearing and freezing the crank?

Edit for wrong advice... See below



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[fabiodriven]

I would put the bearings in the case halves and then take the case halves over the end of the crank



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That's the only way I've done it. Case halves in the oven and bearings in the freezer. They fall right in.

[shortline10]

On the 200 series cranks the bearings are press fit on the crank and they slide in the cases real easy , if your talking 2 stroke motors then the main bearings are installed in the cases first .

[ironchop]

On the 200 series cranks the bearings are press fit on the crank and slide in the cases real easy , if your talking 2 stroke motors then the main bearings are installed in the cases first .

I learned something new. Thanks Mike

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[fabiodriven]

I learned something new. Thanks Mike

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Same here.

[Gabriel]

Not to mention the cam chain drive and oil pump drive gear are pressed on after the bearings are in place.

[Scootertrash]

Ah ok. Looking at a junk crank I have it hardly looks like there is room to get the splitter in there?? Can the bearings be reinstalled by heating the bearing and freezing the crank?

The tool shortline posted is tapered to slip under the outer bearing race as you tighten the nuts evenly. This gets bearing removal started (most of the time) by lifting on the outer race to get the inner race moving. This is why you NEVER reuse a bearing that has been removed by putting a side load on one of the races.



I typically use the hot/cold method to install bearings, as well as lubing the shaft prior to insertion *cough* . It just makes things go a little smoother.

Work smarter not harder.

[Scootertrash]

I learned something new. Thanks Mike

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Me three!