Fix kit?

On the Dragon 800 engines - always fix kit. Stock piston skirts collapse over time and pistons slap around and either the piston skirt or the cylinder skirt will crack and make mincemeat out of your engine... with that said, MtnTek's kit is a little more expensive but has a great reputation. Pistons are taller so less rocking, I believe they are forged, and has a spacer to keep port timing the same. Kelsey / RKTek fix kit is basically custom pistons without the spacer and if you read his web site he can make a pretty good case for his "fix kit" and it does not have an added spacer.

Lots and lots of discussion on snowest forums on this, however since the search sux so badly use google search and then search for "more matches on snowest", here is a sample link to get you started:
https://www.google.com/#q=polaris+piston+fix+kit+site:www.snowest.com

I lost 2 engines with the fit kit installed.

First time lost cylinder skirt on mag side.

Second time SPI pistons beat the **** out of a brand new indy dan monoblock with reinforced cylinder skirts.

RDS88 said:

I lost 2 engines with the fit kit installed.

First time lost cylinder skirt on mag side.

Second time SPI pistons beat the **** out of a brand new indy dan monoblock with reinforced cylinder skirts.

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Wow, that is a bad experience for sure. But in general fix kits are superior to no fix kits by far, lots of good feedback and miles on fix kits in general.

Either that or an 860 Carls with custom cylinders.

late96 said:

2010 800 RMK Assukt, totally stock. fix kit or not when rebuilding top end? And why? Thanks

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Call and talk with Curt @ Fastrax in Puyallup Washington. He will go over your options in detail with you. Great place to do business.

I put a power command on mine before I even rode it the first time, because that's what all the research led me to. I've read that if your in high elevation (9,000 plus) then the mid range issue isn't a issue. Don't know if that's true or not but I ride 500-2500 so I went with the pc. And make sure u have correct weight for your elevation.

You can get a power command fuel controller for $250 or the power command 5 for $450(I think). The difference is the fuel controller can't have a auto tune plugged into it and can't swap between maps with a switch. I went with the fuel controller since neither can control timing anyway just fuel.

Look up dynotech and email Jim there. Tell him what your running, elevation etc and he'll set it up and ship it to your door. Plus the free year access to there write ups is well worth it. Read the stuff.

I rode a 98 xc700 for 12 years and final decided it was time for a upgrade. Not wanting to spend $6k plus I found a 2010 assault with only 1,400 miles for $3.6k (which at the time was a steal) that already was on its 2nd top end due to voltage reg falure. Having read all the scary stuff bout these sleds I did all my homework. Fix kit, Tape up the air box, vent oil cap, turn up oil pump a bit, check tps, T coolant line to meg side head, ethanol wires unplugged, iridium plugs, little oil in the tank. That's just off the top o my head. So far I only have put 75 miles on it cause snow has been absent here for the last 2 years. Runs great so far, no bog or nothing, really strong. But I just can't stand how different it is when the exhaust valves are closed vs open. Kinda like a sportsman 500 below 6,600 rpm when there closed and when they open it wants to flip over. I got sick of coming up to a snow bank, tapping the gas and almost going over backwards. So I read and read and read some more and decided to try plugging the ves hoses, and damn! Much better! Power band is from clutch engage all the way through to 8,200. But if I'm cruising at mid range and stab the throttle I get the det light poping up for a second. So I plug the hoses back in...nope hate it plug em again. So far this year I haven't seen the det light. But I have to figure out where to add fuel if it comes back cause I want this thing to last, which make me wish I woulda got the power command 5 and auto tune so it do it for me.

Kinda a rant but maybe it will help someone

Maybe go with egts and a boondocker box. That way you can see exactly at what rpm your lean at, and had fuel with the BD box

RDS88 said:

Maybe go with egts and a boondocker box. That way you can see exactly at what rpm your lean at, and had fuel with the BD box

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I had egt's on my twin pipe 700 and hated looking at those gauges all the time. I think this time I'd try a afr gauge and already have the ability to add fuel with the power command, but like I said, haven't had the issue so far this year.

Don't use stock pistons... for what stock pistons cost you can buy a fix kit and still have beer money left over.

I'm a fan of the MtnTech kits, have several in Dragons and Pros and have always had good results. Every single one has better snap to the throttle response, but that is probably just because the motor is fresh.

sled_guy