How long can a 2 cycle engine last?
- Thread starter Mafesto
- Start date
But that is a mild 2 S.
I am confident there are no 800 mountain sleds running around w/8000 miles
Last edited:
J
JedInUtah
Well-known member
Not without an engine rebuild, or two by that point.
I am anxious for everyone to throw their hat into the 4-stroke arena and start pushing each other. I would love to have a sled I could ride for 3-4 years after I got it set up to my liking and know it was reliable every time I took it out. I had the chance to ride with Laird of Powerhouse Customs in BC. They are building a custom 4130 tube chassis very similar to a Pro and dropping a Turbo Apex or Nytro motor into them. These things ripped and were very agile. It is possible.
http://powerhousecustoms.ca/
I have had a lot of experience and miles on the 500-600 class snowmobiles and have found them very reliable. Never had motor issues untill the 600etec came out. I am asked often why we do not have 800's for patrol. 2 reasons cost and reliability. I need to be able to get 7-9 thousand miles out of the sled.
93 Polaris 500 - 9500 miles no motor issues
95 Arctic Cat 550 - 6500 miles no motor issues
97 Skidoo 500 - 9500 miles no motor issues
99 Skidoo 500 - 7000 miles no motor issues
01 Yamaha 600 triple - 7500 miles no motor issues
03 600 Skidoo - 7000 miles no motor issues
05 600 Skidoo - 7500 miles no motor issues
07 600 Skidoo SDI - 7500 miles no motor issues
09 600 Skidoo etec - 7500 miles complete burndown 7500 miles
11 600 Skidoo etech - 8300 miles top end rebuild 5500 miles ring pin failure
13 600 Skidoo etech - 2800 miles to date no motor issues
93 Polaris 500 - 9500 miles no motor issues
95 Arctic Cat 550 - 6500 miles no motor issues
97 Skidoo 500 - 9500 miles no motor issues
99 Skidoo 500 - 7000 miles no motor issues
01 Yamaha 600 triple - 7500 miles no motor issues
03 600 Skidoo - 7000 miles no motor issues
05 600 Skidoo - 7500 miles no motor issues
07 600 Skidoo SDI - 7500 miles no motor issues
09 600 Skidoo etec - 7500 miles complete burndown 7500 miles
11 600 Skidoo etech - 8300 miles top end rebuild 5500 miles ring pin failure
13 600 Skidoo etech - 2800 miles to date no motor issues
I would say yes. That's why I went with premix.
Proper tuning and care goes a long ways.
i got over 4k on my m7 on all original internals and still runs like a champ and don't have any plans on opening it up any time soon, i know its not an 800 but two smoke none the less and it gets rode hard just about every weekend through the winter.the fact that some 2 strokes last thousands of miles and some only a few hundred tells me that its not a "2 strokes can't be reliable" issue its a design and/or maintenance issue that causes certain brands to have issues. cat and doo have 15-20ish more ponies than poo with much better reliability says that poos issues is poo related not the fact its a 2 stroke, you would think by now poo would try something different......... that's a lot of poo
on the bike thing, from my experience i would have to agree that a 450 is meaner than a 250 2 stroke. i had a 450 zuke for a few years and it was an awesome bike, loved the power, it got used strictly for trail and dune riding. i beat many a 250 2 smokes in drag races and would climb neck and neck with my brothers kx500 at the dunes. however, i do agree with what was said earlier bout the light 2 strokes getting up on the sand better or something cuz there was times at the dunes where we'd be scraping to get over some of the bigger dunes on the 450s then turn around and see guys on 250 strokes come up with enough momentum to catch air at the top. and last, i don't think the high strung 4 strokes such as mx bikes are any more reliable than two strokes. i changed the oil religiously every 2-3 rides (which does add up at $8 a quart) regularly checked the cam chain and valves and after only about 3 seasons i started seeing metal chunks and flakes in the oil filter so i sold the bike. that being said if i got back into biking i wouldn't hesitate to buy another 450, love the torque and there's just something about being able to pull the front wheel up with ease in any gear.
on the bike thing, from my experience i would have to agree that a 450 is meaner than a 250 2 stroke. i had a 450 zuke for a few years and it was an awesome bike, loved the power, it got used strictly for trail and dune riding. i beat many a 250 2 smokes in drag races and would climb neck and neck with my brothers kx500 at the dunes. however, i do agree with what was said earlier bout the light 2 strokes getting up on the sand better or something cuz there was times at the dunes where we'd be scraping to get over some of the bigger dunes on the 450s then turn around and see guys on 250 strokes come up with enough momentum to catch air at the top. and last, i don't think the high strung 4 strokes such as mx bikes are any more reliable than two strokes. i changed the oil religiously every 2-3 rides (which does add up at $8 a quart) regularly checked the cam chain and valves and after only about 3 seasons i started seeing metal chunks and flakes in the oil filter so i sold the bike. that being said if i got back into biking i wouldn't hesitate to buy another 450, love the torque and there's just something about being able to pull the front wheel up with ease in any gear.
My dad got 6000 miles on his 600 XLT only thing replaced was the chaincase which started slipping.
I've got 3k on my 600, the 600s seem to be fine.
I've got 3k on my 600, the 600s seem to be fine.
Good point.
Now why is that?
Is it because it's a 1000 making 800 class HP? (not living on the edge?)
If that's the case it sure didn't work for Doo's RT sleds!
I opted for the 4-stroke as I boat for 500 hours every summer! 5 oil changes compared to several gallons of expensive 2 stroke oil made my outboard choice easy... I won't mind a 4-stroke sled someday even the weight is scary...
Lifespan
Good question! It would appear the current generation of 800's are considerably less reliable that the 600 and 700's. The longer crank stroke must be a factor. Cooling also seems to be a factor that enters the equation. Leaner fuel/oil? Probably, but not as much a factor IMHO. Higher specific power output has to be a factor.
All bets are off as soon as any mods are done as even modest changes alter the window the designers forecast as 'Normal" operating parameters.
The engineering standard on a snowmobile two stroke engine is 300 hours before a major rebuild. At a 20 mile per hour average that is 6000 miles. 6 and 700's will do that no problem with just a top end. 800's cranks are stressed to get that far. I believe the crank balance is to blame much of the time with sloppy pistons a close second.
Constant but slight detonation is most likely a good guess as a primary problem of many failures of 800's. Takes out top ends and cranks equally fast. Contributing factors are advanced ignition mapping, lean fueling and higher compression. I also believe the knock sensors have a wider variation in QC than many would like to believe. Detonation that one sensor picks up is ignored by another. Some Ski Doo's knock slightly most of the time at part throttle. That and loose pistons lead to failure of the top end in less time than the engineer planned.
It would appear based on all mountain users reports that the top end on a current 800 should be rebuilt at 2500-3000 miles and plan on a crank at 6000 miles as the cost of performance.
Good question! It would appear the current generation of 800's are considerably less reliable that the 600 and 700's. The longer crank stroke must be a factor. Cooling also seems to be a factor that enters the equation. Leaner fuel/oil? Probably, but not as much a factor IMHO. Higher specific power output has to be a factor.
All bets are off as soon as any mods are done as even modest changes alter the window the designers forecast as 'Normal" operating parameters.
The engineering standard on a snowmobile two stroke engine is 300 hours before a major rebuild. At a 20 mile per hour average that is 6000 miles. 6 and 700's will do that no problem with just a top end. 800's cranks are stressed to get that far. I believe the crank balance is to blame much of the time with sloppy pistons a close second.
Constant but slight detonation is most likely a good guess as a primary problem of many failures of 800's. Takes out top ends and cranks equally fast. Contributing factors are advanced ignition mapping, lean fueling and higher compression. I also believe the knock sensors have a wider variation in QC than many would like to believe. Detonation that one sensor picks up is ignored by another. Some Ski Doo's knock slightly most of the time at part throttle. That and loose pistons lead to failure of the top end in less time than the engineer planned.
It would appear based on all mountain users reports that the top end on a current 800 should be rebuilt at 2500-3000 miles and plan on a crank at 6000 miles as the cost of performance.
I have drove a few 4 strokes and I would much rather do a little maintance every 3-4000 miles than have to drive those tanks! The reason I feel they dont last as long as they used to is they are squeezing more HP out of the same cc and leaning them out to meet epa specs. I put 3000 miles on this m8 turbo of mine not one issue now say we take the same motor stock and detune it a little 140HP add just a touch more fuel/oil to the mix (EPA PROBLEM) and I would bet this motor would make 10,000 miles if it can take 3000 at 250hp.
Please god dont let the 2 stoke die!
Please god dont let the 2 stoke die!
K
kingofthemountain
Active member
Personally I can't say much on personal experience with the 800's seeing as I've never had one, but I first got in to sledding on a Yamaha mountain max that I bought used around 3000 miles with pipes and a few other upgrades. I rode that sled hard until almost 10000 miles before It started really losing compression and needed a top end. As an engineer, it blows my mind that these new sleds are needing rebuilt at such low miles. It's completely unacceptable from any angle that I look at it. The only likely explanation I can find for it from an engineering perspective is that it's all a manufacturing ploy to make more money on parts. There is no reason that these sleds, assuming no major modifications and proper maintenance, shouldn't last as long as that old mountain max
C
couch
Well-known member
OK so what does the tube chassis cost? Looks like the answer to me for balance, durability and rigidity!
