Blown!!

[beaners]

Hello!! Just bought a 97 seadoo GTS 720 And one piston is really bad, Cylinder looks like I should be able to get away with honing, Have been looking at kits online and was wondering if I should go with OEM or wiseco? I am really familiar with two stroke snowmobile engines, But when I put the wisecos in them they just didnt seem to last as long before I was rebuilding again. and I dont quite understand the size difference when ordering, I have seen options as .5,1.0,1.5 I would like a little better performance, but would sacrifice some for durability, Also any recommendations for where to purchase/best prices?? Thanks in advance.....

[mibunkerking]

get OEM or Pro-X. wiseco is good but finicky. the numbers represent how big the pistons are. i.e. .25 = .25 over the standard bore.

dont get WSM. you will waste you time and money. trust me on this one

[beaners]

Thanks for the quick reply,,, I believe this is stock, But i take that i need to measure the cylinder for proper size??

[mibunkerking]

to be safe yes. take it to a machinist and have him mic it. then get the correct size over pistons and bore it out to match.

[beaners]

Thanks mibunkerking!! So I have to have the cylinder bored no mater what?? The outside edge of the piston is so eaten away you can actually see the whole ring in places, But the cylinder wall only has minor scuffing. Is it possible to get just standard pistons? Are these nicasil?? I guess my experience with snowmobiles(ie..twostrokes) has lead me to believe this would not be that costly. (with boring etc..) I was really hoping to get a couple of pistons rings etc.. and put this back together, thank you

[Deanrw3]

it does not have to bored over unless it needs to be. he was saying take it to a shop and have the hole measured to ensure that it is withing limits. If so just have it honed and put new pistons and rings in.

if its not the bore and get the next size pistons..

GL
Dean

[mibunkerking]

if the pistons are that bad you need to replace them, not just the rings.

it depends on how bad the cylinder walls are. when you get them miced u will know for sure. now the problem is, you will need new pistons. you need make sure that the piston clearence is not excessive, and since every piston is different when measuring in thousants of an inch, it can get risky buying standard bore pistons with worn cylinder walls.

if you get pistons bigger than the current bore, you can have it bored out to the correct clearence. however, if you order standard bore and the pistons you get are smaller than the current bore, then they will have to much clearence and cause you major problems. if the walls are minorly scuffed, the safe bet will be to go one size over. deep scouring and you may need to go more.

if you get lucky and do get one that will fit, then you can have it honed to the proper clearence and run it. like deanrw3 said, it needs to be in its limits or you will have problems if you dont go the next size up.

the machinist should be able to tell how much he needs to take off to bring the walls back to smooth and round.

the main thing is that you need to find the reason it went out. otherwise it will just happen again.

[beaners]

Thanks!! I will have the cylinder measured, I see it is a steel sleeve, I am just so used to my snowmobiles. They have a nicasil coating, you cant bore unless you resleeve or send out and have it recoated nicasil (best option) From my reading here i guess that i will have my work cut out for me, it still has grey fuel lines on it, So figrureing why this happend will be a major concern. Thanks again

[mibunkerking]

That is the cause right there. The grey fuel lines. They are a motor killer. Change them out and clean your carb filters. Otherwise leave your tools and walet out because the same thing will happen again.

[beaners]

Thanks!! Could someone tell me where I can look into price/buy the pro x, pistons, I have done searches but can seem to come up with prices. Also where would you recommend for the fuel lines?