Modding a fan cooled 550 trail

[Rrrrrrandyw]

Wife has a 2007 Polaris Trail with the fan cooled 550 in it. Was thinking about seeing if I could find some more horsepower in this little motor. Has anyone made any mods to these? And what were the results? She loves the sled, and it is super light, just has hard time climbing some of the stuff that we are riding. Anyone with any suggestions would be greatly appreciated. Might be time to buy her a bigger sled.

 

[rwillower]

first mod that needs to be done in my book is the oil bleeder line valve kit... there is a post on here right now going on about it...get one if you dont already have one... next would be check ur plugs and if it looks a little rich.... take it down one jet size... maybe change the gears for a lil more low end get up n' go

 

[TRS]

put a 155 or 163 on it and gear it down 18/45

 

[Rrrrrrandyw]

I already eliminated the oil injection when I went through the top end two years ago. I pulled plugs the other day, and yes, they do look rich, richer than I like to see them. 18/45 and long track it huh? It can't possibly hurt the top speed as it will only run about 50-55 mph as it is. Thanks guys. I was leaning towards some motor mods and maybe some pipes. But I think I just might start looking for a track. The guy I got it from said more track makes them work much better, I was pretty skeptical.

 

[YDOPEN]

I went from the stock 136 1.25" to a 136 2" on my sons and what a differance it made, I kept the gearing the stock.

 

[TRS]

Here are pictures of two 155's I built one now has a 163 on it. They are awesome little sleds.

 

[retiredpop]

Nice! Where did you get the tunnel?

 

[Rrrrrrandyw]

Here are pictures of two 155's I built one now has a 163 on it. They are awesome little sleds.

Wow! They look really nice. Looks like the one has a can, any other mods? How well do they do in the mountains? I think hers is a 136 x 1 1/2 right now. Maybe some jet changes and a long track with some gearing just might be worthwhile. She has a hard time keeping up with the group right now, but a lot of that could be lack of pressure of the right hand thumb. I have a 151 finger track that I am about to pull out of one of my other sleds. I also have the extensions, so I probably have everything I need. Did they still use the 2.52 drivers in 07? It is still an edge chassis, so I assume it would be. Thanks guys, really appreciate the info here.

 

[Mech Engr]

550

How did you get rid of the oil injection?? I thought you couldn't do that because of the oil lines to the crankcase? Wow, I'd love to get rid of that injection if I could. I have a 2004 Trail RMK (wifes ride).

John

 

[MARV1]

A few years ago one of the mags(I think Snowtech or this one) did one up, shaved head a bit, SLP can for 600, jet up a size due to more compression. Can install deep lug track and gear it way down. Good luck.

 

[Rrrrrrandyw]

How did you get rid of the oil injection?? I thought you couldn't do that because of the oil lines to the crankcase? Wow, I'd love to get rid of that injection if I could. I have a 2004 Trail RMK (wifes ride).

John

I just took it off, I used the block off plate and a blank shaft, I noticed the fitting into the crank shaft and called the friend that I got it from, He runs a large rental department here in Utah, I think he made a couple of calls and was told it would be fine. I put a plug and a hose clamp over the fitting and put it all back together Sled has been out probably 12-15 times per season for the last 2 seasons with out any issues. But really only time will tell for sure.

 

[TimG]

There was a guy on here a few years ago that had done quite a bit of work to one with the objective of having a really light and moderately powerful machine. As I recall, he had it up to about 90 hp. I forget his name, though. Does anyone else remember??

 

[TRS]

Thanks. The tunnel blanks came from Aluminum Components Enterprises in Schofield Wisconsin. 715-241-8711 (Darrel). I trimmed the tunnel. The hole punch is from Mittler Bros. The side extrusions are from a 2000 Polaris RMK (part #1240058). I made the suspension brackets and extrusion supports and powder coated them. The tracks are take offs I had. The suspensions I bought from Tri City, they were take offs and I bought them through their garage sale for $150.00 each (what a steal). The 2.86 drivers and shafts I bought in the swap meet and ebay for $100.00 plus shipping. The can is a HPS for an 09 D8, the stock can is the same as the D8. No oil pump, we are mixing. 18/45 gearing, 60 gram lightning weights, P2 secondary with a 40/36 progressive helix from Dalton. Stock springs. I built them for my grandkids but we have a blast with them. These things are awesome in the mountain for 550's. People cannot believe they are 550's when they see where they go.
In regards to the 07 I'm pretty sure they were 2.52 pitch.

 

[Rrrrrrandyw]

That is what I thought on the drivers, I think I will look around and see what I can find for a track for it. So you also eliminated the oil injection? What did you do about the oil line going to the crank bearing? I found a set of 600 pipes that I am pretty sure will fit it, but not sure if they will create enough back pressure for this motor. That was a steal on the suspensions. You must be around the bountiful area. Always good to meet another snowmobiler who is willing to build what they want. Thanks for the info.

 

[TRS]

Capped the line to the bearing. The cases on the 09 have an oil galley.
There is a guy in Canada that builds pipes for this motor, I will try to remember his name and post it. Maybe some one else can chime in with his number.
We ride Cooke and the Beartooths, we live in Cody.

 

[starrsleds]

i had an aaen pipe on my 01 550 rmk they worked great and sounded great to!! i think the motors are pretty much the same from those years not sure tho.