Oops. Struck a nerve with Chadly. I’ve been super happy with the performance of the four 872 engines I’ve had. I had Roosterbuilt set up the clutching and we ended up with 4 grams more than the base setup on their Big Bore Kit. I’ve also seen first hand how they out perform stockers in deep snow side by side. My 872 174 XM has more pull up top then my 850 175. The 850 seems to be a little stronger down low and in the middle tho. They don’t yank like a turbo but they run dawn to dusk day after day after day. I ride with my two sons and it would have been a nightmare to try and keep 3 turbo sleds running.
850 big bores? No talk all season about them?
- Thread starter pauly815
- Start date
D
What type of piston failure could be expected after 1800 miles?
F
Not quite sure how 1800 miles is just fine and 2200 miles is worn out? Then again, I am not a hillbilly.
The TMS website says they have many with 5K plus miles so you should have no concerns.
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Dave told me to put new pistons in them at 1800. You send in your jugs and they renickel and hone them IIRC. My buddy rode the sled to 2200 miles and it was losing power and burning oil at that point according to him. It didn’t blow up just didn’t work right. He sent in his jugs and got them back ready to go with a new set of pistons and I believe that was under $500.
Dave also said to rebuild the bottom end at 3000 miles. Both hillbillies like me and my friends and flatlanders like FIZ should follow their engine builders recommendations for maintenance and service life of parts.
Ok. I’ll bite. Smoking=burning oil is what I meant. I thought it was clear but I’ll explain for the remedial students. ETECS don’t smoke, or burn oil. They will leave black streaks on the snow sometimes but running well they don’t smoke at all when hot.
OK, further explanation is required. So a well running two stroke burns fuel and a small amount of oil that gets trapped in the combustion chamber. The ring or rings keep MOST of the oil in the cylinder below them and the heat generated is below the flash and/or burn temperature of the oil. As the pistons, rings and cylinders wear over time, let’s say 1800 ish miles in an 872 Trygstad Big bore that ring seal is compromised and MORE oil is exposed to the hot combustion gas and will smoke significantly more than lets say a newer 872 Trygstad Big bore ETEC. Some liquid oil is also blasted out of the exhaust ports into the exhaust pipe and will burn there but not usually enough to see white oil smoke coming from the exhaust.
Hence a heavily smoking 872 Trygstad big bore with upwards of 1800 miles is what I like to call a CLUE. That clue is pointing towards rebuilding the top end or you can listen to Dave and just trust that his advice on engine longevity is accurate when discussing the 872 Trygstad Big bore ETEC. OF WHICH I AM A HUGE FAN!
Hence a heavily smoking 872 Trygstad big bore with upwards of 1800 miles is what I like to call a CLUE. That clue is pointing towards rebuilding the top end or you can listen to Dave and just trust that his advice on engine longevity is accurate when discussing the 872 Trygstad Big bore ETEC. OF WHICH I AM A HUGE FAN!
And this is commonly referred to as Blow by. Great explanation everybody will enjoy it
wheres all that oil hiding as it disappears at 19:1?
That’s a great question. I’ve never seen a smoky 850. Some of it has to burn in the pipe and at 19-1 you’d think they’d smoke. My ProLite was really smoky. Especially before it got warmed up and it had oil delete and I mixed it at 28-1 which I thought was pretty rich oil mix
F
Sounds like you got this allll figured out.
And I do listen to my engine builder. I have been building them for over 30 years..........
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My hotdogger in my turbo smokes my burritos if I do too long of a pull without hood venting. Sometimes can burn the wrapper onto the burritos actually. They are still good and I still eat them.
Nobody can argue that turbos smoke the burritos more after long pulls, especially if your hotdogger is mounted by the Y pipe.
Argument solved!
Nobody can argue that turbos smoke the burritos more after long pulls, especially if your hotdogger is mounted by the Y pipe.
Argument solved!
C
The 927 works, and works well if yah spend the time to tune the clutching, I was disappointed in the 927 at first. Now a well setup 850 won’t come close to a 927.
going to a larger bore with no porting changes over a stock 850 makes how much more power over a stock 850? correct clutching can bring out the power in any sled, including a stock 850, have close to 2000 miles on the 927 with several clutching changes to come up with the right setup for where I ride, also have played with the stock 850 extensively, timing, base gasket, clutching and gearing, in the end the TMS927 is a waste of $2300.00.
Dave will blow a lot of smoke about bad clutching or incorrect fuel management when the real question is why no porting changes over a stock 850 to support the bigger bore 927.
The 872's were very good when properly setup, the 927 not so much!!
Dave will blow a lot of smoke about bad clutching or incorrect fuel management when the real question is why no porting changes over a stock 850 to support the bigger bore 927.
The 872's were very good when properly setup, the 927 not so much!!
Just picked a 2019 sum x considering a 927 but there isn't a lot of info on them. Have had a couple different sleds with BD turbos and never had any real issues at all. Back in the day there was a bit of tuning involved but really that's pretty much a part of owning a modder sled. These days there seems to b little of that. It's hard to stray away from a turbo at 6-8000ft. Not sure how these 850's hold up to boost. I c mtntk has a pump gas available for the 850 now. Uses a small Garrett 2554r turbo.
TMS 927
Caper 11
Thanks for the updated info on doing some clutching and setups on the TMS G-4 927. We have many very satisfied customers in the US, Canada and overseas and at this time are building repeat 927 customers new builds for there 2019 Summits.
To get the full potential of the TMS 927 you do need to run our developed fuel controller with our specific map and correct fuel offsets. Updates are always shared with our customers.
Dave Trygstad
Caper 11
Thanks for the updated info on doing some clutching and setups on the TMS G-4 927. We have many very satisfied customers in the US, Canada and overseas and at this time are building repeat 927 customers new builds for there 2019 Summits.
To get the full potential of the TMS 927 you do need to run our developed fuel controller with our specific map and correct fuel offsets. Updates are always shared with our customers.
Dave Trygstad
2018 RMSHA RACE RESULTS
2017-2018 RMSHA Hillclimb Season just finished up with great results posted by the talented Team Ski Doo racers laying down great runs all season long on the TMS-G4 927.
Jackson Hole Wyoming March 25th 2018.
2nd for Tom Roby in Pro Masters Improved 1000.
2nd for Jay Mentaberry in Pro 1000 Improved.
Pinedale Wyoming April 1st, 2018.
1st for Tom Roby in Pro Masters Improved 1000.
2nd for Trent Handsacker in Pro Masters Improved 1000.
2nd for Jay Mentaberry in Pro 1000 Improved.
Tamarack Resort Idaho April 8th 2018.
1st for Tom Roby in Pro Masters Improved 1000.
2nd for Jay Mentaberry in Pro 1000 Improved.
Grand Targee Wyoming April 22, 2018.
1st for Tom Roby in Pro Masters Improved 1000. Also awarded points championship for season!
1st for Jay Mentaberry in Pro 1000 Improved. Also awarded points championship for season!
Great job guys on the way to finish out the RMSHA Hillclimb Season!
The TMS G-4 927 package that these talented group of racers are using are basically the same as our consumer-blend kits are running over the past two seasons.
* Polaris Factory came up with an Twin Pipe engine package for the 1000 improved racers last season, Ran well but came up short to the above talented racers and the TMS-927.
Wait until the full race version of this great performing engine package is released this coming season on the RMSHA circuit!
2017-2018 RMSHA Hillclimb Season just finished up with great results posted by the talented Team Ski Doo racers laying down great runs all season long on the TMS-G4 927.
Jackson Hole Wyoming March 25th 2018.
2nd for Tom Roby in Pro Masters Improved 1000.
2nd for Jay Mentaberry in Pro 1000 Improved.
Pinedale Wyoming April 1st, 2018.
1st for Tom Roby in Pro Masters Improved 1000.
2nd for Trent Handsacker in Pro Masters Improved 1000.
2nd for Jay Mentaberry in Pro 1000 Improved.
Tamarack Resort Idaho April 8th 2018.
1st for Tom Roby in Pro Masters Improved 1000.
2nd for Jay Mentaberry in Pro 1000 Improved.
Grand Targee Wyoming April 22, 2018.
1st for Tom Roby in Pro Masters Improved 1000. Also awarded points championship for season!
1st for Jay Mentaberry in Pro 1000 Improved. Also awarded points championship for season!
Great job guys on the way to finish out the RMSHA Hillclimb Season!
The TMS G-4 927 package that these talented group of racers are using are basically the same as our consumer-blend kits are running over the past two seasons.
* Polaris Factory came up with an Twin Pipe engine package for the 1000 improved racers last season, Ran well but came up short to the above talented racers and the TMS-927.
Wait until the full race version of this great performing engine package is released this coming season on the RMSHA circuit!
I highly recommend AGAINST the big bore. Either leave it stock and tune the clutching or go with a turbo. I promise you won’t be happy with the BB. The clutching that comes with the kit is complete garbage. It’s revs but doesn’t have any pull. With the recommended setup, a clutched stock 850 will run better and climb higher than the big bore (also first hand experience). If you still think you want to buy one I’ll make you a good deal on mine, it only has 300 miles on it. It’s the most expensive paperweight I own.
- Oct 14, 2008
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Unfortunately, any gains made in horsepower are quickly nullified by the clutches and gearing. There are few, if any, tuners that can get the 850 clutch heat below 200degrees on a long, wfo high load situation.
If anyone can do it, they would have made a video. There are no videos. Can you believe it?
Sent from my SM-G920W8 using Tapatalk
If anyone can do it, they would have made a video. There are no videos. Can you believe it?
Sent from my SM-G920W8 using Tapatalk
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