I understand your point - the difference is that once I got through all the reflashes and got a good PC 5 map, my CFI-4 ran well at 2K miles, 4K miles and 7K miles when I finally opened up the motor. I measured about .008" clearance on the piston skirts when I opened it, not unexpected with pistons that size and that many miles. My CFI-2 on the other hand was kicking butt at 2K miles, started losing RPM by the end of the season. Half expected to find low compression or scuffed pistons when I was checking it over in spring. Nothing "looks" abnormal, but sure seems like something is going on - not sure I want to roll the dice, given that the normal mode of failure is broken parts....
2 Stroke Motor Longevity
- Thread starter nuggetau
- Start date
J
Jaynelson
Well-known member
Makes sense! And just for the record, I don't disagree that manufacturers could build something that lasts a little longer. But it's on us to be realistic I suppose....not a perfect world.
Contrary to popular belief....the for sale section has very definitive proof that piston and or motor replacement at "low" miles is most definitely not as polaris specific a problem as some make it out to be. So maybe rebuilds on interval are the reality....and 5000 trouble free mountain miles are the anomaly...
Contrary to popular belief....the for sale section has very definitive proof that piston and or motor replacement at "low" miles is most definitely not as polaris specific a problem as some make it out to be. So maybe rebuilds on interval are the reality....and 5000 trouble free mountain miles are the anomaly...
Well, I remember back in my 2-stroke dirt bike racing days, that we would replace top ends several times a season. The 125's would get pistons and rings every time and the 250's would get pistons and rings and then just rings every other time. It's a high performance motor!!!
Even bone stock we push these motors to the limits, the way we ride. This ain't your Grandpa's trail sled that is probably still on the original top end from 1994. I agree with 4Z's recommendations. But being kind to your motor (like properly warmed up all day, not just the beginning of the day) goes a long way to longevity.
Remember, gotta pay to play.
Even bone stock we push these motors to the limits, the way we ride. This ain't your Grandpa's trail sled that is probably still on the original top end from 1994. I agree with 4Z's recommendations. But being kind to your motor (like properly warmed up all day, not just the beginning of the day) goes a long way to longevity.
Remember, gotta pay to play.
RMK-King
Super-Moderator
Run a indy dan motor..Proves that quality and correct toleraces will make a engine last a lot longer. The cfi 600 has one of the highest hp/cc ratios out there and they seem to make it 5000+miles before being opened up. I dont see M8 HO motors granading before 2000 miles and they are putting out more power then poo.
Opening up the engine on 140hp 12k sled before 2000 miles is unexceptable imo, the technology and parts are out there to make them last a lot longer,just need to convince the penny pinchers at poo to build it right.
Opening up the engine on 140hp 12k sled before 2000 miles is unexceptable imo, the technology and parts are out there to make them last a lot longer,just need to convince the penny pinchers at poo to build it right.
G
geo
Well-known member
For me, a sled needs to go a season trouble free.
I used to get in about 5000 miles a season when I was younger and things were cheaper but I'm down to about 1700 miles.
When I did the higher miles, if I kept the sled, it was a complete rebuild (crank out and check, seals and rebore, every bearing and bushing from rear wheels to ski bushings, and just about every rivet) to get another season.
I hate down time during the season and to get that many mountain miles you start to head out on your own a lot. Again, in those days I was more than comfortable with a winter camping trip if needed lol.
When the 800's came out (2001 Doo) it seemed the longevity of the 2 stroke went down the tubes ???. I broke my first motor in the hills at 2000 miles (piston skirt)? New grate motor and it lost another skirt at 4400miles but the rest of the sled was very trashed (grease and check every ride) too.
Lesson learned (I think lol) and started buying new every year but after 4 more Doos and 7 warranty motors (last one made a funny sound on a poke and I limped it home, at home I found only 1" of material holding the skirt on the PTO piston).
So while I was waiting for stock on the hot moving BO'ed pistons I bought an 141 M7 (last one in stock) and ran the piss out in (what a fun sled).
Even when the Doo was back together, I rode that sled with nothing but oil, fuel and belts (like it should be) so the next sled was a another M7 and a 5000mile season. The girl who bought from my dealer averages about 600miles a season and it is still in original condition. I see her every year and we share a sunny day out on the snow.
IMO those days are gone and I really don't understand why. Maybe it is planned, but after learning about cheapest bidder the hard way with my '12 Cat I jumped on the Poo Pro.
I didn't expect to break but took a preventative approach (25 to 1 oil on hard rides and wait until the heat exchangers are very warm before throttling hard) and it made 1700 with rings still looking good.
What has been a surprise to me is the rest of the sled and how much fun it was to ride. So I decided doing the front to back rebuild again so I know the cheapest bidder is not in the equation. I now expect 2 more seasons from this build and if no one comes up with anything better I'll do it again in a couple of years.
For me the answer to the original question is 4000miles but I don't believe it is available today in a 800 mountain sled if your looking at the whole package.
To me that is a sad thing. So, I`ll do it myself lol.
I used to get in about 5000 miles a season when I was younger and things were cheaper but I'm down to about 1700 miles.
When I did the higher miles, if I kept the sled, it was a complete rebuild (crank out and check, seals and rebore, every bearing and bushing from rear wheels to ski bushings, and just about every rivet) to get another season.
I hate down time during the season and to get that many mountain miles you start to head out on your own a lot. Again, in those days I was more than comfortable with a winter camping trip if needed lol.
When the 800's came out (2001 Doo) it seemed the longevity of the 2 stroke went down the tubes ???. I broke my first motor in the hills at 2000 miles (piston skirt)? New grate motor and it lost another skirt at 4400miles but the rest of the sled was very trashed (grease and check every ride) too.
Lesson learned (I think lol) and started buying new every year but after 4 more Doos and 7 warranty motors (last one made a funny sound on a poke and I limped it home, at home I found only 1" of material holding the skirt on the PTO piston).
So while I was waiting for stock on the hot moving BO'ed pistons I bought an 141 M7 (last one in stock) and ran the piss out in (what a fun sled).
Even when the Doo was back together, I rode that sled with nothing but oil, fuel and belts (like it should be) so the next sled was a another M7 and a 5000mile season. The girl who bought from my dealer averages about 600miles a season and it is still in original condition. I see her every year and we share a sunny day out on the snow.
IMO those days are gone and I really don't understand why. Maybe it is planned, but after learning about cheapest bidder the hard way with my '12 Cat I jumped on the Poo Pro.
I didn't expect to break but took a preventative approach (25 to 1 oil on hard rides and wait until the heat exchangers are very warm before throttling hard) and it made 1700 with rings still looking good.
What has been a surprise to me is the rest of the sled and how much fun it was to ride. So I decided doing the front to back rebuild again so I know the cheapest bidder is not in the equation. I now expect 2 more seasons from this build and if no one comes up with anything better I'll do it again in a couple of years.
For me the answer to the original question is 4000miles but I don't believe it is available today in a 800 mountain sled if your looking at the whole package.
To me that is a sad thing. So, I`ll do it myself lol.
N
nuggetau
Well-known member
A sled season for most riders is probably under 1000 miles, so they get 2-3 years out of their sled and feel like they got a good return on their money. A different guy rides 3-4000 miles a season and needs to rebuild twice, so he feels like it's too much too often.
There seems to be the perception that skud makes a more reliable motor, I went thru 6 motors in 3 riding seasons(2010-12), none made it more than 2750 miles! I no longer ride skudoo.
There seems to be the perception that skud makes a more reliable motor, I went thru 6 motors in 3 riding seasons(2010-12), none made it more than 2750 miles! I no longer ride skudoo.
I don't mind having to do maintenance on engines like pistons, rings and bearings. Give me a schedule and I will follow it. If they say 1500 miles for pistons I would be fine with that. But what I don't want is the blown engines. If an engine blows up at 1500 miles that is a disaster off warranty, if it just loses performance I can deal with it. All that said we ride very hard, like Jay was talking about. 35 miles in a day is dawn to dusk with a few breaks for water and a powerbar. If my engines make it two seasons with no breakdowns I am happy. I want to do my heavy maintenance off season, gas and oil and tighten fasteners during the season.
Shoot, 10 years ago, a day's ride would be minimum 60 miles, closer to 70 or 80. Five years ago it was 40-50. Now days it seems like 35 is a killer all day long ride. Riding styles have changed and I know that my motor works twice as hard to get 35 miles in today than it did doing 70, 10 years ago. I figure if I can get 2000 miles (3 seasons) before a freshen up, I have done pretty good and have no problem throwing $500 or so at a new top end.
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