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Discussion Starter #1
I thought I would post a build thread for anyone interested in reading/seeing some of the process of bringing an old polaris trailblazer 250 back to life. I bought the quad for my girlfriend to learn to ride. The quad was listed for $500 and I would have to drive about an hr each way the day I found it. When I called the owner about the machine, he said he had a "mechanic" friend take it apart and that it would need a top end for sure and there was a little play in the bottom end. I told him I could only pay $300 for a trailblazer needing a full motor rebuild and being in pieces. He said if I came that day I could have it for $200! I told him I was on my way! We arrive and I start going over the quad. the cylinder was still on but the head was off. The motor wasn't locked up but it did look like it hadn't been running in awhile. We loaded it up and I headed home.

The next day I decided to tear into it to see what I could find. I quickly noticed they had never even pulled the cylinder to determine what was really wrong with the motor. I pulled the cylinder and sure enough... carnage!

 

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Discussion Starter #2
Chunks of the piston skirts had gone everywhere! It also gouged the cylinder wall pretty good right about the exhaust ports. I knew the cases would have to be split in order for there to be no chances of metal being left in the bottom end. So the motor had to come out.

 

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I got the cylinder measured and figured it was going to probably take at least a 1mm overbore to clean the gouges out. A new wiseco piston, full gasket set, and a Ritter Cycle Racing oil injection block off kit with a new throttle cable from were ordered immediately. While waiting on the parts to arrive we decided to sand blast and paint the exhaust with a fresh coat of black.



It was also the perfect time to clean the carb inside and out.


 

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Discussion Starter #4
Once the piston arrived, I had the local shop I used to work at bore the cylinder and clean it up in the media blasting cabinet.


 

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Discussion Starter #5
Getting the flywheel off the crank was a bit of a challenge even with the appropriate tools. I split the bottom end apart to clean the chunks of piston out and make sure all of the bearings were in good shape. Everything went back together and new crank seals were installed to make sure there would be no leaks when it was back together. I installed the new wiseco piston on the crank and made sure everything rotated smoothly.



I then slid the cylinder back over the new piston. Sure is pretty!

 

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Discussion Starter #6
Finally tossed the head on and torqued all of the nuts down. I installed the block off plate for the oil pump from RCR. The motor is together and ready to go back in the chassis. This is currently where I am at. Plans are to get the motor in the chassis before the weekend and start hooking everything back up! Stay tuned!

 

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nice job....lets see when all together an running.....your GF will be happy to ride when done
 

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I am doing the same thing to mine right now too .........do you have to split the case to put the crank seals on? Or can you do it without opening up the bottom end?
 

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I need to get at the mag side crank seal. Do I need a flywheel puller? Manual says you do? Any tricks without the tool? Trying to get this done before it goes back to -20 again........brrrrr.
 

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Great post! I am probably going to crack open the rest of my engine, only have the flywheel cover of now, to check to make sure all the water is out of the casing. Previous owner noticed there was a hole in the air box... only after being pretty far into some muddy water.
 

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Looks to me like you put the wrong crank seal on the pto side......that one should go on the mag side and the all black (w/no metal showing) one goes on the pto side.
 

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also rebuilding 250

ive got a 93 250 trail boss i have to rebuild bottom and might as well do top . any suggestions or places to get step by step
 

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I need to get at the mag side crank seal. Do I need a flywheel puller? Manual says you do? Any tricks without the tool? Trying to get this done before it goes back to -20 again........brrrrr.
take the nut all the way to the end , heat around the fly wheel with little propane torch ( not to close to center) to swell fly wheel a little bit then hit center bolt with hammer firmly while prying behind on both sides of flywheel ( need 2 people ) i learned this today from old fella
 

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Discussion Starter #17
Well this project took a lot longer than anticipated and I forgot to update the thread! The Trail Blazer is alive and running great! The girlfriend is super happy with her first quad and I took her for a day of riding at the local off road park this past weekend. It was a little muddy but the polaris did great all day.

 

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Discussion Starter #18
The next step is to get the electric start working again. She does not like pull starting it and I would rather have it working as it should anyway. Also the exhaust has been welded on and does not line up perfectly like it should. I think a RCR stage 1 kit is in the near future! :D The girlfriend is already begging for another day of riding so I am officially a happy man!
 

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Discussion Starter #20
I took the girlfriend out for her second little riding trip to The Badlands in Attica, Indiana. If any of you are local to indiana or illinois, I highly recommend taking a day trip there. Its a lot of fun with many different types of terrain. The little polaris did great once again. She had even more fun this time because she said she was much more confident in the machines abilities. She still is bugging me to get the electric start working so that is one of the next steps. I have bled the brakes but still feel like they should stop a little better.


I also forgot to mention, since this is a budget build, I am trying to build it for less than what I could have bought one in similar condition. So far with everything I have done, I have less than $500 invested including the price of buying the machine!:banana:
 
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