Turbotater's Porting and Performance Pro RMK 910 big bore install with photos

Scott

Scott Stiegler
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Very cool! Would love to see the stroker build.


I would LOVE to do that, after seeing how they are running. BUT, this was more my budget, since I just needed a top-end refresh anyway.
 

Merlin

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Great build thread Scott!

Should be lots of fun when once it's dialed.

Darn near missed reading this completely since it's General Snowmobiling section......
 

Visi

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Few Questions

What was the squish before the domes were milled?

What did the squish end up at that you are running?

What clutching are you running? (Best way to compare to my PG turbo)

Squish should tell you what kind of fuel you need to run but what are you running fuel wise?

Sorry if I over looked some of those things.
 

Scott

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Displacement= 910cc
Bore is 91mm
Stroke is 70mm
Head volume=54cc (was 53cc before we put it on the lathe)
Compression=13.13:1
Squish= .060 both cyls (I think it was .052 before we turned it on the lathe)
Cranking compression= 120psi @ 4000’ elevation
Exhaust duration= exhaust 204°, intake 129°

Riding elevations are from 4500-8500 feet.
Straight premium 91.5 octane pump gas with 1.5oz of Klotz octane booster per gallon of fuel.
 

Scott

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Why was this moved?
IT's probably better fitted here.

Maybe I missed it, what kinda hp is this kit? cost?



I don't know the HP. I haven't seen a dyno sheet. Wayde's got these 910s for just under the $3k range.


The stroked 910 is a 962cc. It's a different type of project. It's in the $5k range. It's an ANIMAL with GREAT harmonics. I saw the vid of it racing a pump gas turbo on 7lbs. NECK AND NECK!!!!

I think Wayde will post his prices here.
 

Dbook

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IT's probably better fitted here.





I don't know the HP. I haven't seen a dyno sheet. Wayde's got these 910s for just under the $3k range.


The stroked 910 is a 962cc. It's a different type of project. It's in the $5k range. It's an ANIMAL with GREAT harmonics. I saw the vid of it racing a pump gas turbo on 7lbs. NECK AND NECK!!!!

I think Wayde will post his prices here.



Oh god the video again..... LMAO!
 

Scott

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Getting​ some spring hours on this and she's been getting better as she goes.
And now that I'm better at tuning the electronics, she's making more power and running cleaner.
 

Merlin

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How is the performance on the top end?

Feedback from alot of owners of other big bores claim substantial improvement in bottom to midrange with little, to no, improvement at the top. Not sure if that is a result of improper tuning or simply a shortcoming in the design of the kit?

It'd be nice to see a big bore package deliver for the Pro the way the Carls & Union Bay engines did for the Edge.



Getting​ some spring hours on this and she's been getting better as she goes.
And now that I'm better at tuning the electronics, she's making more power and running cleaner.
 

Scott

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How is the performance on the top end?

Feedback from alot of owners of other big bores claim substantial improvement in bottom to midrange with little, to no, improvement at the top. Not sure if that is a result of improper tuning or simply a shortcoming in the design of the kit?

It'd be nice to see a big bore package deliver for the Pro the way the Carls & Union Bay engines did for the Edge.



Yep, bottom and mid range are nice and violent.
Top end is coming along. I have had it quite rich, so as I lean it, it's doing what I want it to do.
I'm also considering a bit thicker base gasket too...I'll let you know if that happens.
 

Scott

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Summer update.
Just about the time I figured out that I was full of "error on the safe side" by running some extra fat numbers on the Dobeck, my TPS went totally crazy on my last couple rides in May/June.
No, those two aren't related, but it was a little of "went from one problem to the next". Lol
Nothing major and nothing to do with the big bore runability, quality or durability.


Summer updates from Polaris dealer:
Fresh TPS.
checked reed petals
checked/cleaned injectors
pistons checked (heads not pulled)

Can't wait for snow.
 
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Merlin

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Any updates on your big bore Scott?



Summer update.
Just about the time I figured out that I was full of "error on the safe side" by running some extra fat numbers on the Dobeck, my TPS went totally crazy on my last couple rides in May/June.
No, those two aren't related, but it was a little of "went from one problem to the next". Lol
Nothing major and nothing to do with the big bore runability, quality or durability.


Summer updates from Polaris dealer:
Fresh TPS.
checked reed petals
checked/cleaned injectors
pistons checked (heads not pulled)

Can't wait for snow.
 

Scott

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Yes I haD to replace my motor mounts , primary clutch, stator, jackshaft, and brake bearing.

My pipe has been rubbing on the frame. We believe that's what was causing all the DET issues. Those DET sensor are just a microphone and are very sensitive. It will pick up the vibrations from the pipe rubbing on the frame every time. I'll pick up my shed tonight.

When I wasn't getting the DET issue it freaking runs great.
 
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Merlin

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Should be good as new after all of the repairs.

How's the pull on the top end? You mentioned having the fueling on the fat side last season.....



Yes I haD to replace my motor mounts , primary clutch, stator, jackshaft, and brake bearing.

My pipe has been rubbing on the frame. We believe that's what was causing all the DET issues. Those DET sensor are just a microphone and are very sensitive. It will pick up the vibrations from the pipe rubbing on the frame every time. I'll pick up my shed tonight.

When I wasn't getting the DET issue it freaking runs great.
 

Clarke_67

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Scott care to share the head stud specs or where you got them from? Nice build. That poor kid is in trouble seeing all that black magic at his age 👍.

I know I'm digging up an old thread but how is she doing now? I'm tearing into a fresh wiseco forged piston built 12 engine i did to port the crank case and smooth up the transfer ports. Also takeing the steel plate out to install a custom aluminum base plate with pins between it. The block, and the head. Maybe a little late, but an old mod i have been doing for years is running a det sensor zip tied to my coolant hose. If in happy with tuning and doing something like a race, or high consequence climbe, I unplug the head mounted det sensor and plug in the one to make sure the coolant system is doing OK 👌 lol
 

Scott

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This sled had been so awesome.
I need to sell at least one of my sleds, so I would consider selling this one and the 2016 600 rmk 155.

There are sure no mechanical issues with this engine or the sled, so I sure hate to sell it, but mama wants a new 2021 in Plum Crazy
 

Scott

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I don't know the stud specs.
Wayde will know them though.
The poor kid has grown into a big bore lover now. Haha.
He's also developed an affinity for boost at 17 years old.

Scott care to share the head stud specs or where you got them from? Nice build. That poor kid is in trouble seeing all that black magic at his age 👍.

I know I'm digging up an old thread but how is she doing now? I'm tearing into a fresh wiseco forged piston built 12 engine i did to port the crank case and smooth up the transfer ports. Also takeing the steel plate out to install a custom aluminum base plate with pins between it. The block, and the head. Maybe a little late, but an old mod i have been doing for years is running a det sensor zip tied to my coolant hose. If in happy with tuning and doing something like a race, or high consequence climbe, I unplug the head mounted det sensor and plug in the one to make sure the coolant system is doing OK 👌 lol
 

Scott

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I sold my 600.
Anyone interested in this 910?
 
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