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crank is tight

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Anybody have an explanation on why my rebuild crank would be tight ..I just put the cases together and it went together very nice.until I tighten'd the bolts  Tranny turns nice. Do you think crank is out of balance..Crank moves nice for half turn than stops.

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How did you install the crank, and what crank are you using?

Did you install new crank bearings?

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Give the crank a smack side to side with a rubber mallet or dead blow on both ends, assuming you used the heat/cool method of installing crank/bearings there might still be some pressure on the bearings side to side

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Yes new crank bearings used the heat cool method ,oem crank with new rod . I was playing around with it for a few minutes at my noon lunch and it almost seems like the plastic inserts on the crank is hitting the bottom of the case. after I loosened the bolts.  is it out of balance. A little disappointing. Should I bring back to shop that changed the rod and tell them that it may be out. oh ya this  is a 08 yz250 

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Holy crap I decided to have a go at it again and took your advise bloodbmcg and it worked freed right up thanks

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Give the crank a smack side to side with a rubber mallet or dead blow on both ends, assuming you used the heat/cool method of installing crank/bearings there might still be some pressure on the bearings side to side

You have to do this sometimes to free them up. I had to do the same to mine recently and most cranks have installed.

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Most of the time its because the crank bearings were not fully seated when installed

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ok it freed up for a while ..I heated both sides up then gave them a smack and it worked.. but as it cooled down it started to stick again  should I just keep giving it a smack till it stops sticking

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The last time I had my cases split I encountered the same thing. The crank was too close to the clutch side of the case and it had a slight drag. As stated I tapped it towards the other direction and it freed up. If it still seems bound up try pulling on the opposite side while you're tapping. That may help.

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Sounds like your bearings aren't seated properly.

I agree.

 

To fix it, without splitting the cases again, I would use a crank puller (eg. Tusk) and pull the crank fully left, then fully right, and that will seat each main bearing squarely and fully in each case half. Then install the puller on the opposite side one more time, and pull the crank back to the middle.

 

Today I found that the crank moves inside the bearings before the bearings move in the case.

 

If you remove the reed block you should might see the lateral position of the crank without removing the PV actuator and cylinder.

 

Next time you install new main bearings, get the cases hotter and bearing cooler, and when you drop it in, it should fall all the way. I used a household freezer and an electric heat blower, and it worked fine. But I did heat the alum on both sides. No seal installed of course.

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I'm not a big fan of installing bearings with out a bearing driver. Just asking for a problem. I freeze the bearings and drive them in. All the way to be exact you can tell when the sound changes etc from experience .

Edited by Jd267

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