How do you remove wrist pin

[chas57006]

I have a 2001 supersport 550 fan that quit.

How do the wrist pins come out of the piston, do you need a special tool for this?

I have taken the head off and the top part of the piston on the exhaust side is pitted and pieces broken off. Looks like I will have to bore the cylinder.

Is this from running it too lean?

 

[ADRENALINE]

Hi! If you aren't sure why it burnt down I would take it to someone who can check out the engine to make sure you aren't lean, lack of lubrication etc. Also you have to watch how many particles ended up in the case as you might be removing the engine from the sled for repairs. As to how to remove the wrist pin, it depends on which side and how accessible it is once again taking the engine out and putting on a bench might be the best way. Wrist pins are held in by circlips then you can push/pull the pin out of the piston however a lot of times it isn't that easy and requires a puller. If you aren't sure or haven't worked around engines, I would advise taking it to a dealer.

Kent
Adrenaline Powersport Accessories

 

[chas57006]

repair

I am mechanically inclined and understand two stroke motors although I have never had to take one apart.

I took it to the black hills, used 250 jets and raised the needles to the top clip. I am thinking that I should have left the needles alone.

Right now I don't have the money to have someone else fix my sled so I need to figure out how to do it myself.

Thanks for any help you can give.
Charlie

 

[Ron]

The best way is with a puller made for pulling wrist pins. Remove the clip as mentioned and use a puller. Careful removing the clip or it will end up in the crank case, use some rags to cover the openings.
You can probably drive the pin out but will need someone to hold the piston so that you don't stress the connecting rod. The right size socket & extention with gentle taps with a hammer will do the job-if you are careful.

 

[frog]

I have a 2001 supersport 550 fan that quit.

How do the wrist pins come out of the piston, do you need a special tool for this?

I have taken the head off and the top part of the piston on the exhaust side is pitted and pieces broken off. Looks like I will have to bore the cylinder.

Is this from running it too lean?

In 2001 they had an issue with engine failures on the 550 fan cooled engines. I worked at a dealer back then and if my memorey is correct polaris was recommending the use of heavier weights (60G I think) and also there was a new CDI box with a revised timig curve for better engine durability. Your best bet is to call Polaris customer service and be very civil with them. Give them your VIN# so they can run it to see if any updates apply and if any have been done. You will more than likely have to repair the engine on your own dime but if there are any updates those parts and labor will be covered by polaris.

Once the cyl is removed and the retaining clip is removed for the wrist pin you can heat up the piston with a heat gun and push out the wrist pin with a 6" long 3/8 extension. Make sure you use a glove cause the piston will be quite warm. When reinstalling the pin (most piston kits come with new pins and retaining clips) just put the new pin in the freezer for about 1/2 hr and it should slide in nicely without having to heat the new piston. Remember that the locating pins for the rings face the intake and if there is an arrow on the piston top it should point either to the exhaust or towards the flywheel (cannot remember what the 550 pistons have but polaris used both indicators.)

Good luck.

 

[frog]

Sorry, didn't see you were at altitude but there still should be a revised weight chart and check on that new cdi box.

 

[ADRENALINE]

Excellent remarks by Frog and Ron. Sounds to me like it was lean, so you must have went down in jet size prior to your trip? Take it a step at a time, might not hurt to pull both cylinders while you are there just to check the other side. Also make sure you cover the case prior to removing the circlip so it doesn't fall in.

 

[BB454]

Piston

Chunks broken off often inficates detenation. Did you have good fuel? If they are lean, they usually look like the edge is sanded off. Does it have a reg/prem ignition switch? If so what setting were you running in?

Moving to the top groove definately leaned it down in the bottom and mid range. Doesn't affect wide open. What speed were you going when it started acting up. If at half throttle or less then the dropped needle was the likely the cause.