I believe it will, but I'm just checking before I spend $250. You wouldn't believe how hard it is to find on of this things.

 

400fnSport,

The part number for the cylinder on my 400 is: 3086753. Call your local polaris dealer and ask him if that is the same part number for the Sportsman 400. If so, you would then know that polaris uses/has used the same cylinder from 95 to 2001. Hope this helps.

Waylan

 

400fn Sport,

It will fit. How well it will work is another story. The cylinders for the 1995 (and later on the Xplorers) are tuned for low end power. You may have to do extensive porting to get it to Sport/ Scrambler specs.

 

The 95 cylinder will fit the 98 .

You will have to get a 95 carb boot to attach to the cylinder , that will cost about $45.

The 95 cylinder does not have the 2 small ports at the bottom of the intakes .

The reed cage is also on at a different angle. This is the reason you need a new carb boot .

What is wrong with your 98 cylinder ?

 

Sounds like to me I need to do more searching for one along the line of my year.

Rick, my cylinder sleeve has separated from the cylinder itself. It's like a little hairline fracture. And it has been causing uneven ring wear, and eventually causing my bore to increase which has caused the piston to start slapping, and no compression. I had some pics posted of it not to long ago, but no one told me if it could be fixed. I don't know if it is worth it considering it would cost me the money to fix the crack, plus going to a .060 bore, and another new piston. I'm just thinking of trashing it and getting another one. Because I have 3 pistons setting here, and they have only about a couple of hours on them. So that would save me the money I would spend on a new piston. I was hoping to find a used on that I could bore and stick one of these pistons in, but I didn't think I would have this much trouble finding one. But here are the pics of my problems.CylinderSperation

 

Rick,

If I'm not mistaken the pistons might be different too.

 

That's right Mike , the piston windows are a bit different from early to late models .

The separation at your cylinder top , does it make you lose coolant ? I don't really see why it would cause uneven ring wear . Are you sure that is the reason for your troubles ?

 

Rick,

I know 400fnSport, and was in Arkansas with him last time the bike had troubles. It was on a fresh rebuild, and it had great compression......ran really strong. One afternoon, he added a passenger, and was poking along for a little while and when he went to open it up, he said it lost all power and went dead. He had to be towed back. It cranked later, but was low on compression and ran poorly. I may not have the story 100% correct, but I believe it is close. 400fnSport, correct anything that I've not stated right.

This is the same engine that was wearing the rings egg-shaped.

 

Thats right, it was off a 2nd fresh rebuild. Probably no more than 12 hours on it before it bit the dust. The first time I rebuilt it, the rings were worn just like it was after I got back from Arkansas. Here is a pic of one of the rings. It's hard to see the wear, but it's between the 10 o'clock & 12 o'clock position. And the side of the ring thats worn is where the cylinder seperation is occuring. Here is a close up of a normal ring, and the corner of the worn ring I believe whats happening is when the cylinder is expands and contracts from heat, the side the sleeve is seperated from is pushing against the piston causing it to eat the corner of the rings, and pushing against the cylinder causing it to wear my bore which is causing my piston to slap. What walexa is talking about when we were in Arkansas, is my quad was running fine, but I did notice that the sound of my exhaust changed. It got a lot higher pitched, then when me and a buddy of mine took some girls out on a ride, we hit a straight trail which he decided to floor it on and pulled away. As I attempted to do the same, it sounded like someone turned the ignition off. After getting pulled back, I removed the spark plug, and it had a lot of carbon build up. It started up after cleaning, but I knew it wasn't the same. After I tore it down, I notice it did the same thing it did after the first rebuild.

Also, that one cylinder I was going to buy, I decided to back out of it since it has been bored .040 over. I felt $250 was to much, and I could just buy a new one for a little more.

 

I took a look at all your photos and I have a few thoughts and can tell you what I have seen personally.

I have seen rapid ring wear like that before and three of the most common reasons are dirt entering the engine (via the aircleaner), an oiling problem , or to coarse of a wall finish left by the honing proccess .

Check your airbox for signs of collected dust where only clean air should be . The dust will collect in the rubber boot and be mixed with a little *carb spitback* leaving a little *gas/dirt mud looking stuff* . wipe a white tissue in the black rubber boot behind the carburetor and have a look .

What type of oil are you using in your injector ? You would think that an oiling problem would result in a locked motor , but many times it will show itself in the form of prematurely worn rings .

The *fouling* on that sparkplug , collected dirt ? I have seen that before too . Heavily oiled engines that leave oil foul deposits are not very likely to wear rings like you are experiencing.

It was very observant of you to notice the separation at the top of your cylinder , but in my opinion , I don't think it is the reason for rapid ring wear .

I would hate to see you buy a cylinder , only to have this problem resurface in another 12 hours . ~~~Just trying to help~~~