2 Stroke CR250 Clutch removal problem - flywheel stuck on shaft

Trfsrfr

Trfsrfr

I got the transmission issue figured out, but this thing is still giving me problems :banghead:.

Because the threaded end of this crankshaft is on the left side and that's what my puller/installer fits, I installed the crank into the left casing at first. It rotated freely and was nice nice.
Then I ran into trouble trying to mate the 2 halves together. When I went to rotate the crank it rubbed somewhere.

So I separated the 2 halves, and the crank and bearing stayed with the right side, and it rubbed in the right half somewhere.
So I pressed out the crank and right side bearing, the left bearing is still in the case.

I assume I'm not the first with these issues. Whats the trick here?
I used a heat gun and froze the bearings to install.
 
Mihylo33

Mihylo33

Trfsrfr:
I got the transmission issue figured out, but this thing is still giving me problems :banghead:.

Because the threaded end of this crankshaft is on the left side and that's what my puller/installer fits, I installed the crank into the left casing at first. It rotated freely and was nice nice.
Then I ran into trouble trying to mate the 2 halves together. When I went to rotate the crank it rubbed somewhere.

So I separated the 2 halves, and the crank and bearing stayed with the right side, and it rubbed in the right half somewhere.
So I pressed out the crank and right side bearing, the left bearing is still in the case.

I assume I'm not the first with these issues. Whats the trick here?
I used a heat gun and froze the bearings to install.
Click to expand...

Sometimes you need to tap the crank from side to side on the ends just so it seats. Other times it’s a missing bushing, a missing washer, misaligned case half, missing gasket.
 
O

ossagp

there shouldn't be any spacers that go on the shafts ahead of the mains. The CR's like the 250 you are on will basically change postion when you assemble them and tighten that spacer when the primary gears is put on and tightened that the power side main seal rides on. that will tell it where it is going to be in relationship to the bearing. Since you didn't ask before, it is a little late to put it in the way I like, but I would assemble with said spacer tightened down and if you feel bind simply smack the fywheel end of the crankshaf about 30-45 degrees of the shaft itself. The bind should disappear. I hate getting that far and finding that. Other bikes have a similar thing take place when the primary gear is put on and tightened in a lot of cases.
 
Trfsrfr

Trfsrfr

Mihylo33:
Sometimes you need to tap the crank from side to side on the ends just so it seats.
Click to expand...
I tried that. Tapped it all over, and no go.
I think I'll try again with dried ice, and put the halves in the oven instead of using the heat gun...
 
Trfsrfr

Trfsrfr

ossagp:
oh you got it apart again?
Click to expand...
Yes, the left bearing is still in the case though but will get removed shortly.
I'm going to buy some dry ice now. I'll check back in a bit...

Edit: Got the dry ice and both bearings are chilling on it now.
 
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Trfsrfr

Trfsrfr

Man, there is no substitute for dry ice.
Yesterday when I put the bearings in, I just had them in the freezer for a few hours first. But they did not go in as easily as they just did now after being on the dry ice for 2 hours. I could easily spin them in their holes ensuring that they were flat-bottomed.

I'll put the crank in the right side case-half tomorrow morning and see how that goes.
 
Trfsrfr

Trfsrfr

I do like a press, but much prefer a large vice and a third set of hands.
There's more allowable finesse to a vice, and you can ease it along, whereas a press...one stroke too much and ka-blammo, shit flies to pieces.
 
Trfsrfr

Trfsrfr

Put it back together again, its still binding somewhere.
Bearings went in super smooth yesterday. Install the crank in right side today and it binds somewhere in the right half.
I thought maybe the left half would help straighten things out when mated with the right but no such luck, it just got more locked up.
 
Mihylo33

Mihylo33

Quick question(s).
Were there 2 gaskets on the cases when you split them?
Are you sure it’s the crank binding and not one of the drives?
 
Trfsrfr

Trfsrfr

There was only one gasket.
Yes, its the crank.
Bearings spin fine, but it binds when installed into the right side case.
When I say binds, I mean the cranks spins, and then stops in one spot. When forced through the spot I can hear something hitting/rubbing.
I'm beginning to wonder if the crank was maybe dropped or something, and maybe now its untrued? It came from RMATV, a Wiseco set...
 
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Mihylo33

Mihylo33

Trfsrfr:
There was only one gasket.
Yes, its the crank.
Bearings spin fine, but it binds when installed into the right side case.
When I say binds, I mean the cranks spins, and then stops in one spot. When forced through the spot I can hear something hitting/rubbing.
I'm beginning to wonder if the crank was maybe dropped or something, and maybe now its untrued? It came from RMATV, a Wiseco set...
Click to expand...


It might be untrue but you wouldn’t know until it started or you take it to a shop and have them balance it.
 
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