2 Stroke Motor Longevity

[nuggetau]

We have endlessly debated the motor reliability issue, and the determining factor for each persons satisfaction seems to be based on their expectations for longevity without repair. Which begs the question, How far does the motor have to go to meet your expectations?

For example: If the motor needs a new top end or crank before XXXX miles I feel like it has failed to meet my standards for reliability/longevity.

 

[mickyd32]

Well I can come at this from a few different angles. My current sled is going to the shop to possibly get a top end done. I have a thread going about compression issues already. Basically '13 Pro, 2300 miles, 105 compression on each side, lookes like the pistons are flaking below the lower ring.

How does this make me feel? not extatic, but I also realize that I don't ride easy, and this is in fact a 2 stroke motor. I have seen many of all brands make far less miles. Mine still feels like it is running strong, but tests show otherwise. A new top end refress after 2300 miles isn't the end of the world to me

That being said, I rode a Doo a while back, ate a motor every 500 miles like clock work. 4 crate motors in just over a year. Spent more time in the shop than riding. This was not acceptable to me

Also have had a few 600s go into the 8xxx and 10xxx mile range before needing repair. One due to operator neglegance. This to me is well beyond my expectations of what a 2 stroke should put out. I would be quite happy with in the 4-5000 mile range. This is a solid 2 seasons of riding for me

 

[canj]

I never owned an unreliable sled so it's hard for me to tell. The last time I needed to do a job on one of my engines was on my 1991 skidoo cheyenne in the late 90s (over 10k miles). My riding buddy burned 4 piston/cylinder in 3 years on his 2003 600ho summit. I teached him how to do the job by himself the first time hopefully for me!

 

[AndrettiDog]

I too have never had an unreliable two-stroke. I've had two Dragon's, Two Pro's, one Edge and an IQR. None have had motor problems unless I screwed something up on my tinkering. I expect a sled to last me 2-3 years as that's the longest I usually keep them. But that being said, I expect to be able to sell a sled and not be worried about a guy buying it and having it $h!t the bed. Mile wise, I think it is reasonable to go 2500-3000 and then doing a top end refresh (check pistons, cylinders and do new rings, rollers, pins and gaskets). Just the cost of owning a two stroke. You can say all you want about different two stroke brands, but I think my mileage theory applies to them all.

 

[bigchevrolet]

My first 800 clean fire would sh$t the bed every 1000 miles. 5 top ends and one crank in two years.800ho cat 3200 miles no issues.06 600 ho polaris 8300 miles which included many trips to hell and back zero issues. Xcr800 5000 no problems 12 800 pro new crank at 3500 as odd as it may sound the less modified my machines are the more prone tey are to failure.....I don't understand but most definitely how it works out

 

[AdrenalineAddict]

I feel a well designed bottom end should run for 4,000 to 5,000 miles depending on type of use. With double row and wide bearing technology your cases shouldn't be out of tolerance at 3,000 like the old days. I also feel a well designed top end should match the life of the bottom end, Yamaha pulled it off for years with their two strokes, some ran 7,000 miles without ever giving them a second look. Does Yamaha have a design secret nobody else is tuned into or are these motors suppose to be disposable? My Pro 800 has been pretty decent although pistons were scuffed at 2,100, bottom end is still holding up at 3,200. Time will tell if the bottom end makes 4,000 to 5,000.

 

[miko700]

reliability edges performance for me!

If polaris said they were going to make an 800 engine that will go a good 3000 miles but they had to add 25 pounds to it to make it happen it would be the only sled Id buy! Honestly most most 800 cc's and up will do just about anything we want to do as riders. I'm all for modding things to the point of insanity if thats what guys is after (been there!). Out of my crews 4 pros 3 blew at 1400 miles or less. Two top ends and a crank snapped at the primary. So at the end of the day it is what it is thats sleddin! and I love the changes made in the 11's and up, the suspension and "rideability" of the sled is awesome! And it has made all of us carry an organized tool/rope/safetycombo! BUT im gettin kinda tired of pullin or bein pulled out of pemberton for these 8 hour tow trips were takin to get out of the mountains and home . (videos furnished upon request! ) LOL.......DEALERS answer "just buy a new one every year"..... Polaris I love ya! BUT!!!!!! for the 2105 great sled!!!! leave it alone but focus on RELIABILITY! REMEMBER! the old slogan was "THE WAY OUT" I want that to work both ways. Out for the day.......and out of the mountains when im done..............................oh ya one last thing.... BRAAAAAAAAAAAAAAAAAAAAAAAAAAP!

 

[Norway]

I feel a well designed bottom end should run for 4,000 to 5,000 miles depending on type of use. With double row and wide bearing technology your cases shouldn't be out of tolerance at 3,000 like the old days. I also feel a well designed top end should match the life of the bottom end, Yamaha pulled it off for years with their two strokes, some ran 7,000 miles without ever giving them a second look. Does Yamaha have a design secret nobody else is tuned into or are these motors suppose to be disposable? My Pro 800 has been pretty decent although pistons were scuffed at 2,100, bottom end is still holding up at 3,200. Time will tell if the bottom end makes 4,000 to 5,000.

I hear ya, and I would like the world to be like that to. But I fear that although we may have a case against polaris for the CFI-4 and to some degree the CFI-2, we are up against the EPA here.

Maybe Yamaha quit the 2-stroke game because they saw what was coming? Maybe they tried to build engines that passed the emission tests, but could not make them last?

I've said it before; would like to give my pro a throttle house from a CFI-4 so I can have the injectors in the intake. That way you can add oil to the lower end via fuel and you can cool your pistons with your fuel, just like "the good old days".

 

[2XM3]

just depends on how hard you push it, when I ran the slp 903 race motor (205 hp) I was happy to get 400-500 miles out of pistons.... my 2 stroke mercury 2.5 drag motors set on kill, maybe 25 dragstrip runs on the rings if that. I would be very pleased if I ran my 2014 hard and had to change pistons at 1200-1500 miles

Remember this, in horsepower per displacement we are basicly running a prostock motor and asking it to live....lol

 

[nuggetau]

Maybe I should have phrased it differently. Do you think it is realistic to expect 3000 miles from the top end and 6000+ from the bottom? Yes or no

 

[villain]

I would think anything beyond half of that ran hard is good. At least that's what my expectations are.

 

[nuggetau]

just depends on how hard you push it, when I ran the slp 903 race motor (205 hp) I was happy to get 400-500 miles out of pistons.... my 2 stroke mercury 2.5 drag motors set on kill, maybe 25 dragstrip runs on the rings if that. I would be very pleased if I ran my 2014 hard and had to change pistons at 1200-1500 miles

Remember this, in horsepower per displacement we are basicly running a prostock motor and asking it to live....lol

That is the crux of the motor reliability/dependability debate. Expectations! There are many guys like you who think 1500 is adequate, while there are many who think 3000+ should be the benchmark. That is a big discrepancy in expectations. That is why I wanted us to have this discussion to see if we could form some realistic consensus for what the "expected" longevity should be for our 2 stroke motors.

I see posts where people brag that they have 700 miles on their sled without any problems. Are our expectations really that low? Kinda like saying your 2 year old son's joints don't have arthritis yet!

 

[harf69]

I'd be happy if I got 3000 out of a top end and have a rebuild able lower end at 6k but I watched a buddys sled go down at 2200 box stock not even a can

 

[2XM3]

For a bone stock pro I would expect 2000 miles with zero issues, then top end if its cared for properly....

hows that ? lol

 

[nuggetau]

For a bone stock pro I would expect 2000 miles with zero issues, then top end if its cared for properly....

hows that ? lol

That is what I am looking for, I want everyone to chime in with what they think is adequate.

 

[Jaynelson]

The other variable here is....what kind of miles.

I would expect quite a few more trail/flat miles out of motor X, than deep pow miles. I've been in deep enough snow that you had to be completely pegged to go up the road. Last winter there was a section of road that I know is just over 3kms long and I was all-in for the entire stretch at almost-getting-stuck speed. You don't have to be a genius to know that is hard on a high-strung motor.

 

[Norway]

For a bone stock pro I would expect 2000 miles with zero issues, then top end if its cared for properly....

hows that ? lol

Now you're more inline with my thinking! And I would say back in the day that 3K miles were good on a top end without any ring/piston/cylinder problems.

As for prostock... My benchmark for a 1000cc prostock woul be 240-260Hp, NO BS!!! Multiply by 0,8 = 190-210Hp... That is a PG turbo pro..

RS

 

[4Z]

High load riding (deep, steep, ice cap) 1,500 miles on top end, 5,500 on bottom end.

Flat land bar hopping 3,000 miles on top end, 9,000+ on bottom end.

Mixture of both, lands somewhere in the middle.....

 

[rocket]

High load riding (deep, steep, ice cap) 1,500 miles on top end, 5,500 on bottom end.

Flat land bar hopping 3,000 miles on top end, 9,000+ on bottom end.

Mixture of both, lands somewhere in the middle.....

3K on a top end won't even make it through a season for some of us in the flatlands. Even my "POS" CFI-4 800 ran 2 seasons without being opened up. Anything less than that is unacceptable and I'm not sure my Pro is going to make it. I don't believe for a minute that 2-stroke motors "can't" last longer than they do, they just can't be built out of parts sourced from the lowest bidder....

 

[Jaynelson]

3K on a top end won't even make it through a season for some of us in the flatlands. Even my "POS" CFI-4 800 ran 2 seasons without being opened up. Anything less than that is unacceptable and I'm not sure my Pro is going to make it. I don't believe for a minute that 2-stroke motors "can't" last longer than they do, they just can't be built out of parts sourced from the lowest bidder....

If you ran 6,000 miles+ on a CFI-4, then I can't see why you wouldn't give it shot on a CFI-2. You obviously weren't overly concerned with blowing up one, so why the other? I mean that truthfully, not being a smartass. Personally, I think that's really pushing your luck, and a $500 or less piston kit when you are spending $2,500+ per season on gas alone to run that many miles is peanuts.

At the dealership I worked at, a guy bought a brand new Tacoma off the lot...drove it for a few years without EVER changing or adding any oil....put on about 58,000 miles until he baked the engine. Probably "saved" about $600 on oil changes by the recommended schedule. Even, say, $150 worth of oil changes (still far from ideal) would have drastically improved his overall engine life. So by that notion, apparently you CAN drive a Tacoma about 50,000 miles on the factory oil...................but I wouldn't recommend it. There are likely other vehicles and other manufacturer's who's engines might not make it that long, and others that will go longer.......but it's still not the best idea.