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bottom end- crank hard to turn..

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03 cr125

Just split my case to clean debris that fell in the crankcase. Crank spun freely by hand before dis-assembly. couldn't split the cases by hand (I was impatient) so I started smacking the crank with a rubber mallet:bonk:. after pounding it good and hard, they came apart. Put a few new tranny bearings in and all new seals.

When I'm putting the two case halves together the crank turns freely until I torque the case bolts down. Once its torqued, it turns, but not very easily at all. did I mess the crank up when I was giving it a good and hard pounding? Is it possible that the seals are touching the bearings and slowing it down?

If I did jack up the crank? whats the best way of fixing the problem? new crank (its a semi new Hot-Rods crank)? Getting it serviced (where and how much?)?

Anybody's 2 cents would be greatly appreciated! thanks!

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It just doesn't sit properly in the main bearings. How did you install the crank in the bearings? Heating/freezing?

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You may have to remove the main bearings from the crank and install them in the case halves. As of now you have a slight side load on them preventing them from spinning when torqued. I had a similar problem on my YZ. Once I put the bearings in the case all was good. Best of luck.

Mark

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Look at the crank sitting in the cases with them together. There should be an equal gap on both sides. If one side has a bigger gap than the other it'll bind up like your stating.

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I had the same problem. Left side crank shaft was not fully seated in left bearing. I pulled it in by putting old crank bearings under the flywheel nut (flywheel not installed, ofcourse) and torqueing the nut so that it pulls the crank into the bearing. You will here some pop noise when it goes through the bearing and then it spinned freely.

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It's what FPMXer said. The crank got pushed over to one side of the case during assembly. Take a plastic or lead mallet and tap either end of the crankshaft to center it up. You'll feel it begin to turn freely as you do this.

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thanks guys. seems like really good info. I'll try it out.

the bearing fits very tightly on the left side of the crank. I'll try to tap it with a mallet first to see if I can get it to sit perfect so itll spin well. If that doesn't work I'll have to use a splitter and get the halves apart.

On reassembly maybe I'll freeze the crank first to help it slide on better and prevent binding...

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If it was hard to put the crank into the bearing then I would guess that it is not fully seated in the bearing so tapping might not help.

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The crank is a light press fit inside of the bearing, the crank will sometimes be hard to put in the bearing. Most of the time, the crank will get pushed to one side of the crankcase during assembly. The crank will be tight when this happens. Tapping the ends with a mallet is the best way to re-center the crank.

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is it by eye you measure the crank "centeredness" (new word) or with feeler gauges.....

I just finished the bottom end in my honda 94 cr 125 and the crank looks to be sitting a bit to the left or closer to the left case.

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