Oh No! Another Pro Burn Down Thread – Sorry

[RMK900Tractor]

Another thing I noticed tonight as I am tearing down the engine is oil leaking out the shaft seal on the mag side. I assumed the engine would pull a vacuum and suck air in along with any oil and not push oil out. The side that seized was the PTO side and not this side. Any thoughts on this oil leakage??

 

[XCaSSAULT]

That seal is shot.

The pressure in a 2 stroke fluctuates constantly from negative to positive.

The bad mag side seal would not effect the pto side.

The mag side seal might not have been leaking air yet but it’s knocking on the door.

 

[Grizzly44]

Someone also mentioned the oil reservoir cap may be a problem. I took off the cap today and when I shake it - it makes a rattle sound.

However, if I try to blow air with my mouth in or out of either the inside or outside I am not able to make air pass through.

It would seem to me air should pass through to equalize the pressure inside the tank to atmosphere.

Does anybody know if this is normal?

Hi - the cap can be a huge problem because if it does not breathe, there will be a vacuum created as the oil is used and will cause NO OIL being mixed into the fuel. Then you lose your engine.. Mine rattles too, and breathes but I watch the oil consumption very closely.,

 

[Reg2view]

Stock cap breather is only open when the cap is vertical, and the ball inside is bumping the vent open. Since the cap sits at an angle on the pro tanks, the cap isn't open at level and standing still, only when the ball is rattling around. There are options, Passo cap, Doo Summit cap with duckbill, both pass air regardless of position. Drilling a small hole works, but will weep oil when rolled up.

 

[Snowmow]

Stock cap breather is only open when the cap is vertical, and the ball inside is bumping the vent open. Since the cap sits at an angle on the pro tanks, the cap isn't open at level and standing still, only when the ball is rattling around. There are options, Passo cap, Doo Summit cap with duckbill, both pass air regardless of position. Drilling a small hole works, but will weep oil when rolled up.

Doesn’t matter what position the cap is in ( vertical or horizontal) or anywhere in between. The ball has to knock the peg around for the tank to vent. Which on a pro the cap sits at an angle that makes filling easier. So on a groomed trail ride venting won’t ever happen.

The doo cap is where it’s at. $12

 

[RMK900Tractor]

I do not run a Indy specialty’s motor. I bought into all the hype of the fix kits with forged pistons.

That was before I read his rant about forged pistons. That alone has not shifted my opinion on forged.

Back in my short track, wide open across a lake days taught me cast is a safer more reliable bet then forged. 2 stokes in general don’t play well with consistent throttle in any range. Varied throttle is obviously best.

Can forged work...yes of course. But if your gonna run forged your gonna have to be more aware of how u use your sled, like longer warm ups and waiting for temps to settle down after short stops, lots of varied throttle, etc. plus u better be on top of maintnece like fuel filter change every season, valve cleanings, and no gas older then a month.

Cast has a much better chance of surviving when things get out of the “perfect” zone of all those things. That’s prolly why polaris and all other manufacturers chose to run them.

I won’t belive anyone who says they can feel a noticeable difference in performance between cast and forged. (That be fun, line up 6 exact same sled, only one has forged, see if a expert can tell)

I’m not a forged basher. They have a place. I have them in my sled now. But if your talking reliability. Cast is the way to go.

What do all of you think about the SPI Hyperdryve Piston as a replacement option?

 

[caddylover]

good pistons!. I have forged in my Pro R now but when i rebuild, i'll put the the Hyperdrives in instead. I have had very good luck with SPI in all my other sleds as well. Thousands of miles on them

 

[gtwitch]

I have read this post twice now and I have failed to see where you have checked fuel pressure and/or replaced the fuel filter or both!!!! This could be the problem that cause a lean condition and burn down both cylinders. Just my train of thought here, because I lost an engine on my MY 11, 800 PRO because of a fuel filter getting restricted!
gtwitch in wyoming

 

[RMK900Tractor]

I have read this post twice now and I have failed to see where you have checked fuel pressure and/or replaced the fuel filter or both!!!! This could be the problem that causes a lean condition and burn down both cylinders. Just my train of thought here, because I lost an engine on my MY 11, 800 PRO because of a fuel filter getting restricted!
gtwitch in wyoming

Good thought, I did replace the fuel filter last season before the burndown. However, I have not checked the fuel pressure. My plan is to replace the fuel pump this year anyway. Also, I found a place to test / clean the injectors.

 

[RMK900Tractor]

good pistons!. I have forged in my Pro R now but when i rebuild, i'll put the the Hyperdrives in instead. I have had very good luck with SPI in all my other sleds as well. Thousands of miles on them

Wondering if SPI Hyperdrive pistons have a "fix kit" version that can be installed with my MTNTK Fix Kit? The kit originally had the Wisco forged pistons in this kit but not going back to forged but would still like to use the fix kit spacer if possible.

I have searched in attempts to find an SPI catalog or part number reference but seems impossible to find any information.

Anybody know the piston part numbers for the standard and the "fix kit" versions?

 

[caddylover]

not that i know of. Regular SPI pistons do IIRC, but not the Hyperdrive.

 

[Daag44]

Another thing I noticed tonight as I am tearing down the engine is oil leaking out the shaft seal on the mag side. I assumed the engine would pull a vacuum and suck air in along with any oil and not push oil out. The side that seized was the PTO side and not this side. Any thoughts on this oil leakage??

It pulls a vacuum for each stroke as the piston rises, but also create pressure when the piston falls. The pressure pulses are stronger than the vacuum pulses.

 

[diamonddave]

Wondering if SPI Hyperdrive pistons have a "fix kit" version that can be installed with my MTNTK Fix Kit? The kit originally had the Wisco forged pistons in this kit but not going back to forged but would still like to use the fix kit spacer if possible.

I have searched in attempts to find an SPI catalog or part number reference but seems impossible to find any information.

Anybody know the piston part numbers for the standard and the "fix kit" versions?

Why would you not use the forged pistons in the MTNTK kit? Have you somehow confirmed that they are the reason your motor went down?

And no, you do not want to go mixing different pistons to shims. They are matched dimensionally shim height to piston.

 

[Daag44]

Here are some pics from inside the Y pipe.

Fantastic pictures of the y-pipe. So now you know why it failed, rebuild with good parts and this time run a wideband so that next time you'll see a problem before it happens. You won't need to be glued to the gauge either. Just enough to ensure the rebuild is being fed enough fuel and then the odd glance just like you would with the engine temp gauge. The difference is when you see DET on the gauge then you have the Wideband to tell you what's going on like a loss in fuel flow.

It's a lot better than being puzzled by the DET showing on the screen. If it isn't fuel flow then it's likely octane or perhaps way too much Ethanol, but the last two can be avoided for the most part so that leaves fuel flow. So if DET shows up and the Wideband clearly shows too lean, then it's time to stop the sled and look at the muffler temps. With a y-pipe like you showed I would imagine the muffler would have been red hot in places and at night it would glow in the snow like a neon light.

I've seen this on several occasions with a 600 SDI that comes to mind. It was scary hot with the plastic panel feeling like butter. In this case it was the injectors and a different driver. Sled was lent out to someone who didn't know of the particular lean spot at a particular rpm range and throttle position. The owner never rode long in that range so there was never a problem until he lent it out. Diamonddave makes excellent points from beginning to end. Everything he mentioned I learned from Doo and Poo SDI.

For the pistons, either stay with the same kit or go OEM. I don't see why after reading Dan's posts that you would contemplate the cheapo cast. Of course the break-in should be enabled after any rebuild, or do it manually which is more trouble.

By the way, the big thing that is missing on the older doo/poo SDIs is the DET warning. That is a gift on your sled to be used.

Right tools for the right job.

 

[Daag44]

Why would you not use the forged pistons in the MTNTK kit? Have you somehow confirmed that they are the reason your motor went down?

And no, you do not want to go mixing different pistons to shims. They are matched dimensionally shim height to piston.

One look at the y-pipe and it wasn't the pistons.

Are the pistons taller like what was done to the Patriot 850? What clearance do you use?

 

[RMK900Tractor]

One look at the y-pipe and it wasn't the pistons.

Are the pistons taller like what was done to the Patriot 850? What clearance do you use?

Sorry, I missed your post.

I am not sure but I sent 1 of the pistons along with the cylinder to be replated at Millennium Technologies. They tolerance it to the MTNTK kit instructions: RING END GAP - .019”-.028”
PISTON TO CYLINDER CLEARANCE – NOT LESS THAN .004”

 

[RMK900Tractor]

Update,

Slow progress this summer but now some snow on the ground so decided to get back to work on it.

Below is a list of updates and my progress,

- Change crank seals - Done
- Cylinder reworked - Done at US Chrome. Plated and bored to match pistons
- Have someone check the crank indexing & bearings – Done at Northern Crank Shafts. Replace 2 rods and PTO bearing
- New set of injectors – Checked, cleaned, flow tested at local engine shop.
- New MAP sensor – on the list to be done
- New exhaust sensor (nobody mentioned this, but I do know it is there to monitor the pipe temperature so if it gets too hot it richens the air/fuel mixture) – on the list to be done. Anybody know how to test?
- Better venting in the oil reservoir – Will get the Doo cap
- MTNTK lightweight pistons – Decided against MTNTK and purchased SPI Hyperdrive
- Adjust the TPS sensor to richen up the air/fuel mixture (always had a detonation issue once the MTNTK kit was installed so must be making more power than stock so need a bit more fuel) - on the list to be done
- Oil Pump – Turned up
- New fuel pump – on the list to be done
- Check fuel pressure - on the list to be done
- Coolant bypass - on the list to be done. Anybody have one of those $28 kits for sale or an Engine-Tech or Terra Alps thermostat housing for sale?
- Drain fuel tank - on the list to be done
- Clean electrical contacts and apply dielectric grease - on the list to be done
- Clean clutches – on the list to be done
- Oil pump & water pump seals - Done

Anything that I am missing?

Thanks!

 

[RMK900Tractor]

I have another question about the cross shaft cavity where the cross shaft is driven off the crankshaft which drives the oil and water pump.

If I remember correctly when I disassembled the engine I seem to remember this cavity being filled with 2-stroke injector oil but I could be wrong.

I read through the service manual but it does not mention anything about filling this cavity with oil.

I did get the crankshaft rebuilt at Northern Crankshafts and it came back to with some grease coating the water/oil pump drive gear.

Any input will be appreciated.

 

[RickCA]

what is the best method to go about cleaning the electrical connections without damaging them. what type of cleaner are you guys using, is there a write up someone can link me?

 

[cubby]

they make electrical cleaner and sell it at all the parts stores, then put some electrical grease in it before connecting it again