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LeakDown results- post em up

willjogervais

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At 20 miles 1.5%, at 340 3.5% and 132- 133 psi. I don't have papers in front of me and dont remember the hours off hand. Compression raised a cpl psi with more hours, I assume from rings getting broken in

Edit- both tests were done cold w 100 psi . I run polaris ves oil

Just a continuation if anyone was curious. I've been keeping track of mine since I picked it up in early December. I had to back out of a trip so don't have as many miles as I'd like yet but it is what it is. I've never had a problem with this sled and it has ran great. At this point, I'm not worried, but I'd be lying if I said I wasn't just a little concerned with the leakdown tests creeping higher. Although they were done in a colder enviroment this last time around (not sure if that affects it much). Hoping to sneak out west one more time to put some more miles on the wknd of the 28th-31st if I can find somewhere with good snow/weather and I will check it again.

504 miles, 42 engine hours
4.25% - 4.5% leakdown both sides
132psi both sides
This last test, both were done when sled hadn't ran for a week in a semi-heated garage at 45* compared to 60* in my shop for the earlier tests.
 

Chadly

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The 850 better start worrying about the Cat...... the Alpha is one badazz machine.

Polaris will not get good consistant performance feedback until they get their cylinder finish problem fixed.

Inconsistant cylinder finish means inconsistant piston life.....which sad to say leads to sleds that run complete different within the same exact model.

Dan

I think Cat should start worrying about Polaris. With the new homoerotic colors of the Khaos all the lifer Cat guys are going to switch to Polaris :face-icon-small-dis
 

indydan

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Just a continuation if anyone was curious. I've been keeping track of mine since I picked it up in early December. I had to back out of a trip so don't have as many miles as I'd like yet but it is what it is. I've never had a problem with this sled and it has ran great. At this point, I'm not worried, but I'd be lying if I said I wasn't just a little concerned with the leakdown tests creeping higher. Although they were done in a colder enviroment this last time around (not sure if that affects it much). Hoping to sneak out west one more time to put some more miles on the wknd of the 28th-31st if I can find somewhere with good snow/weather and I will check it again.

504 miles, 42 engine hours
4.25% - 4.5% leakdown both sides
132psi both sides
This last test, both were done when sled hadn't ran for a week in a semi-heated garage at 45* compared to 60* in my shop for the earlier tests.

You are doing yourself a great service by testing your motor as you go.

You know more about your motor right now...... then if you took it to 99% of the Polaris dealers out there and ask for a health report on your motor.

Not to slam dealers but but for the most part most just don’t do leak down tests.

I would be concerned as well..... it’s dangerously close to needing a top end.

I hope you get another trip in.

If it goes past 5% it needs to come apart.

Dan
 

A@ron

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There is a massive difference between ( not mechanically inclined) and lazy.

A leak down test should be done if you are having any kind of performance problem....... Bogging, hasitating, not going into reverse, hard starting.not pulling rpm, poor idling & so on.

Bearing problems ?????????? If you have a bearing problem...... The results are almost always the same..... The motor will soon lock up.

If you do a leak down on 2 different sleds.....

Sled 1 - has 6%

Sled 2 - has 2%

Then you go ride both sleds...... You instantly understand the value of a leak down test.

The 2% will run substantially better in every way.

The 6% sled needs top-end work...... No need to trouble shoot it until the top-end is fixed.

This thread proves.....that the masses would rather wonder what's wrong and talk endlessly about small problems then do a leak down test.

We did put in a large order of leak down testers that should be in soon and we are also going to do a YouTube video showing how it's done if anyone is wants to
See the procedure performed.

Dan

got a link to the video?
 

Prayn4snow

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I repeated the leak down test on my 850 with a different test kit and ended up with the same results as my more expensive tester. The cheaper one is an OTC 5609 on line.
My tests using 100psi at TDC was 98 which = 2% leak down. I only use Polaris Extreme oil. Test done at room temp and motor cooled to touch after running. If you haven't done one before I would use something soft (like a Q-tip) to find TDC top dead center after pulling your spark plugs. Of course do 1 cylinder at a time, but you will need something or someone to hold the primary clutch from spinning once you add air pressure. Do not damage your clutch!! A clutch tool from SLP works great or you could be careful and use a wooden broom handle. Once I find TDC I put a sharpie mark on the end of the clutch bolt so I know it hasn't rotated under pressure.
1st pic is gauge hooked up before air pressure added.
2nd pic is with 100psi shown on left gauge, right gauge is how much the cylinder is holding.
3rd is Operating instructions. At the bottom you will see that my cylinder at 100psi held 98psi which translates to 2 percentage of leakage.
4th Cheap kit that can be ordered on line for cheap at less than 1/5th of my "good brand" that showed the same results.
5th OTC cheap compression tester. Didn't read as high as my higher $ tester, but it was consistent on several cylinders I tested. When I test compression with any tester, I only compare prior readings from the same tester for this reason. What is more important to me it the pressure differential between cylinders. For example if one is 130psi, and the next one is 115psi you have a problem.
6th is the cheap compression test kit part # 5606
7th is my reference above about marking the clutch bolt once you've found TDC.
Hope this helps.

So some people have put their sleds away for the season and some are still lucky enough to still ride. If your still concerned over this and need help (Ive walked a couple people through this over the phone). Your welcome to stop by my shop if your in Upper MI. Ive also done a couple in my enclosed trailer out west. I keep a separate tester in there if you see me out or stop by if your in the Yoop (Send me a PM 1st). I'm guessing "most" sleds are fine but some are still nervous over this. If your numbers are low, the off season would be a good time to get it to the dealership.
 
Last edited:

AndrettiDog

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All these posts and 3 or 4 people have posted leak down numbers. Seems all these threads are about IndyDan now.
 

indydan

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All these posts and 3 or 4 people have posted leak down numbers. Seems all these threads are about IndyDan now.

What do you mean by this ?

Leak down tests are the only way to check the the true condition of the top end.

it’s surprising how many people will not do it.

performance problems cannot be trouble shot accurately without leak down numbers.

Dan
 

Prayn4snow

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Quote:
Originally Posted by AndrettiDog View Post
All these posts and 3 or 4 people have posted leak down numbers. Seems all these threads are about IndyDan now.

What do you mean by this ?

Leak down tests are the only way to check the the true condition of the top end.

it’s surprising how many people will not do it.

performance problems cannot be trouble shot accurately without leak down numbers.

Dan
Quote:
Originally Posted by Sheer View Post
"This whole thing seems like a giant waste of time to me... unless you have a prob with your sled, low power, runability.... why bother... its not known for top end issues for 1, 2, if you suspect something bring it to dealer and get them to do it, you got a 4 year warrenty why not use it??? 3, if you dont trust the dealer or think the diag is wrong yea shure maby than do it... aside from that if your want to know where your engine sits than shure go ahead.. but i got better things to do than leakdown test a brand new sled.... maby i will go check the amp draw in the heating element of my brand new coffee maker just so i can keep tabs on it till it goes off warrenty"

I get this so this is my past reply:
(Originally Posted by Prayn4snow) "Sheer, I total understand your point. "Most" people will never do this or need to do it. The OP wanted people that did this test to simply post results. There were comments from some that wanted to know the how to do it and what to use. I simply like to help people make up their own minds if a product (bumpers, pipes, tracks, gearing, big bore, clutching, piston durability kits, turbo's etc) are right for them. Im the type that does these tests regardless for my own 2 cents. I have a log of base lines for each sled and race car I build. I just twisted the crank a year ago on a ProCharged (Intercooled supercharger) 70 Corvette for example. When you risk smoking a $15,000 motor you tend to look at the little things including ultra balancing rotating items. In this case the manufacture of the crank rated it to over 1000hp. I made 1000 my goal, and with enough boost and the right bolt on components and machining this is now a reachable goal. Because I documented everything the crank manufacture had to admit they messed up.
These are useful tools, and 4 years of warranty is rare in snowmobiling. These test are helpful for the 1 year warranty baseline, diagnosis, buying used sleds (or any engine). Its quick, easy, fairly cheap (some parts stores will rent you the tools for a day even) and for some gives peace of mind. Others are weirdos with ADD like me, I don't know, my teacher said I was special but my mom had me tested . Enjoy the snow and the sled"

To each there own on if you should do a leak down test to create a base line. For me this had nothing to do with Indy Dan. Yes, he has some valuable insite and recommendations. And yes he is good at ruffling peoples feathers lol. Regardless of what people think about him his shop does outstanding machine shop and engine work which is a fact. The other fact is leak down tests if done correctly don't lie and give you the owner a valuable tool of insight that you cant get from another means shy of complete teardown, measurements and inspection, even then it's still valuable.
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1Mike900

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Wouldn't a single ring leak down faster than a double ring at the end gap, unless the single ring end gap overlaps? What is the std. end gap on a 3.34" bore? Seems like it would just leak real fast unless oil was taking up the space.
Mike
 

indydan

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Wouldn't a single ring leak down faster than a double ring at the end gap, unless the single ring end gap overlaps? What is the std. end gap on a 3.34" bore? Seems like it would just leak real fast unless oil was taking up the space.
Mike

Great question....... I can't give a 100% positive answer to that.

But my opinion is that 12 rings would be about the same as one ring.

Zero difference in leak down numbers. ( if the rings are set up correctly )

In a 3.346 / 85mm bore ( Top ring ) end gap on a modern 2 stroke would be about .018.....

( Lower ring ) I don't care much about this one as long as it's bigger then the top ring.

And it's vital that lower ring end gap is bigger ( to make sure there is no pressure created in between the rings ) causing the upper key stone ring to float and not allow it to get the floor making the bottom ring the primary ring.

The bottom ring is not a performance helper...... It's along of the ride.

It's main help to the motor getting heat out of the piston into the cooling system via the cylinder bath.

Single ring set ups are fine.

As I have said a thousand times...... In a silicon carbide plated motor it's all about ( cylinder finish ) the smoother the better.

Nice write up ( praying for snow )

Dan
 
J

jim

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For me this had nothing to do with Indy Dan. Yes, he has some valuable insite and recommendations. And yes he is good at ruffling peoples feathers lol.

He just states the facts...a lot of people simply have permanently ruffled feathers from a chronic case of knowitallness.
 
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