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Two stroke top end install issue

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I have a 2003 rm250 and decided to do a piston and ring install today. I used a wiseco kit. I have done several top ends before with no issues. Well I could not get the wrist pin to fit in the piston. Of course I kept trying and trying and f'd up the piston so now I need to order a new kit.

 

Has anyone run into where the wrist pin was this tight? I am talking it started peeling the inside of the piston when I tried to press it in. I knew they were tight but this was ridiculous. Any suggestions or help would be appreciated.  

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Yeah I kinda figured that. I bought it off amazon. I should have just got it at rockymountain like I normally would.

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Had this issue a few weeks ago with a wiseco forged kit. I battled for quite a while, swore, considered sending it back, then eventually whacked the piston and wrist pin into the freezer for a couple hours like I should have in the first place, and was able to get it in. Not easy mind you, but noticeably easier than it was beforehand. If you haven't found another solution already, trying putting all the parts in the freezer for a awhile then do the install before it warms up and expands. 

Edited by Porkchop Sandwich
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If it's a tight fit you could try freezing the wrist pin, and put the piston in the oven at 230 F for about a half hour.  You can also make a puller from a piece of threaded rod, two nuts, and two washers.  The rod must be small enough in diameter to fit through the wrist pin.  Line the pin up for insertion into the piston.  Run the rod through the wrist pin so that it extends out one end of the wrist pin and all the way through the piston until it extends out the opposite side of the piston.  Place a washer and nut on each end of the rod and tighten the nuts.....pin will "pull" nicely into the piston.  The application of steady, gradual, evenly distributed pressure/force is SO much better than striking where possible.  Does the upper rod bearing slide easily onto the pin?

 

But as Bushpig said, it's normally removing that's the issue....usually can be pushed in by hand when installing...

 

Rule #1......NEVER force anything.  It it doesn't fit easily take a step back, a deep breath, and re-assess because likely something is wrong, or something is being done wrong ;)

Edited by Fattonz

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