would you re-use this piston?

[yz400ex]

I have an 05 900.. needs the top end rebuilt.. I have a spare motor which lost 1 side piston and cylinder after only 6 starts on a brand new rebuild due to a cylinder defect.. I now need 2 pistons for my current motor and was wondering if you guys would recommend using the 1 oem piston and rings I pulled out of the damaged motor with another brand new oem piston and rings? Piston looks to be in good shape, but does have spots where the coating is flaking on it. Other than that, cleaned up it looks to be almost new, but due to it coming out of a damaged motor do you still think it would be safe to run?? Thanks for the advise.

 

[ADRENALINE]

I'm no expert on the 900 but I would definitely make sure your cylinder will accept it (clearance wise) as something could have happened to the piston, like colapsed skirts etc. Cylinders become egg shaped and putting a new piston on old surface is never a good idea. Good looking piston though, but once again, maybe the 900's need certain clearance to hold together.

 

[bossmans kid]

re-use pistin

After six starts, the piston has alrady started to form to the previous cyalander. I would buy a new piston kit.

 

[yz400ex]

Yea, not sure either.. thats why I asked.. I have never re-used a piston before, but this thing literally had 6 starts on it.. not rides.. starts.. when the other side crapped out.. This is the only reason I ask..

 

[eddy]

Piston

Measure it to the specs and if it is within tolerance use it!

 

[river]

was that cylinder good that the piston came out of?I would use it in the same cylinder as long as it was good.piston looks like new

 

[HUNDO]

I think if I had it down that far, I'd just throw a new one in. You can always keep that one as a spare so you have parts if you, or one of your fellow 900 riders, need one mid season.

 

[Himark]

hate to say it but if your going to sell sled or own it short term I would use it. If not put a matched new pair in. Take all those reman car motors they are using old good parts and only putting in parts needed to rebuild. This is common practice.

 

[snowmobiler]

id run it.

 

[Super Dave3]

Piston

id run it.

X2 That piston looks great.

 

[knoba]

05 pistons

Some people had problems with the 05 pistons so if they are not 06 pistons i would replace them with 06 pistons.

 

[XC700116]

There is no such thing as a "matched pair" of Polaris pistons unless you go through a huge stock of them and mic and weigh a bunch to find 2 that are the same. They are all sold, shipped and packaged individually.

Measure the piston diameter at the wrist pin (opposite the direction of the pin) and compare that to the same measurement down on the skirt, if it's within about 5 thousandths use it, if not and within 10 (collapsed only and not bigger than the other dimension on both the 5 and 10 numbers) then save it for an emergency, going riding and smoked a piston, weekend. Outside of 10-12 use it for a pen holder.

Either way if/when you put it back in put a fresh set of rings in and hone the cylinder if you can to get a fresh ring seat.

Judging by the pictures alone, I'd run it with fresh rings.

 

[XC700116]

Some people had problems with the 05 pistons so if they are not 06 pistons i would replace them with 06 pistons.

Oh and that is an updated 06 piston.

 

[yz400ex]

wow, didnt think I would get so many responses..some say run, some say dont.. The piston does look new, it is an 06 piston, I still have the entire motor the piston came out of (will be building it as a backup motor) so I do still have the cylinder, but figured I would just ask if it should be run or not.. I will check the specs on it and go from there.. I just didnt want to just drop this in w/out asking the opinions of the pros here.. Thanks for all the responses..

 

[FLASH1970]

Measure the piston and if it's in spec I'd use it. Get a bore gauge and measure the cylinder to make sure it is in spec as well. When looking at the top of the piston, measure at the 12-6, 1:30-7:30,3-9, & 10:30-4:30 so you know if it is out of round. Do that towards the top of the piston, just before half way down the piston, just after half way down the piston, and near the bottom. Do the same for the cylinder wall.

I know someone mentioned re-honing the cylinder. If it still has the cross-hatches in it and is still in spec for "roundness" I wouldn't hone it. If it is out of spec, only hone it if you have the proper machine to do so. One of those "spring loaded attach to your drill" things are garbage and do more damage than good. The rings won't seat properly and you'll get blow-by...

 

[paramuir]

Just watch what you run, make sure that if you use this that you are either running two 05 pistons or two 06 pistons, no mixing and matching.

Last season thought that i had 06 pistons in the sled and when one side went down replaced it with an 06 and then one week ofter the other side went, turns out i had one 05 and one 06

 

[yz400ex]

I understand this.. You can no longer buy 05 pistons. If you look at the part #'s on a fiche it will give the same part # from 05 as it does for 06 since the 06 replaced these.. I still have the OEM boxes from these pistons from new and they are the 06 pistons..


What if I just used the cylinder and piston from the bad motor and put onto my running motor? This way if the piston had tried to form to the cylinder, it would still have the same cylinder it was forming to. This had been mentioned earlier, but what are the thoughts on this from anyone else?

 

[Ex-Member]

I think if I had it down that far, I'd just throw a new one in. You can always keep that one as a spare so you have parts if you, or one of your fellow 900 riders, need one mid season.

Yep; i'd just replace 'em.

 

[yz400ex]

Yep; i'd just replace 'em.

http://www.sled-parts.com/sledparts/sledparts_engine_spi.html

Thanks for the response.. The link you posted is for the SPI pistons though..They are a great price, but they also say for 05.. Are these still the direct copies of the POS 05 pistons or have they updated their design to now copy the updated 06 pistons? I am always down for saving money, but dont want to save a few $$ now and spend a whole bunch later on other parts because the pistons were crap..