• I've received emails and PM's asking me about "Group Buys" and promotions.

    A Group Buy here on SnoWestOnline.com would be a situation where a normal member (non vendor or mfg) personally collects orders from other members. That member then uses those orders to negotiate a better price with the Vendor/Mfg for HIS/HER "Group" of buyers.

    Here is an example of a viable "Group Buy"

    http://www.snowestonline.com/forum/showthread.php?t=269222

    A promotion that has the words "Group Buy" in the title is still a promotion, and from the rules that were handed down to me by Harris Publications is that non-advertisers cannot run promotions or open sales programs on the forums outside of the swapmeet.

    If a members wants to become a group buy manager, maintain a thread and collect the funds and negotiate a group buy... as a member, you are welcome to do that as long as you are not attached to the business of the vendor or Mfg.

    If you are a vendor/MFG and you want to offer an EXCLUSIVE "SnoWestOnline ONLY" promotion that is exclusive to snowest readers, please contact me and you'll be able to put it up in the Polaris forums.

    Also, before any vendors/mfgs get all "riled up" over this know that the moderators are strictly volunteers and do not receive a dime from any advertising $$ spent on this site.

    As ALWAYS, since DAY ONE of me becoming a moderator, I have pioneered, supported and encouraged vendors and mfgs in getting the word out to our readers with "New Product Announcements.

    Have a great season.

    From this point on, all vendors/mfg's promoting Pre-Season tiered sales programs, in the Polaris Forums, that are not paid advertisers will be appropriately moved to the swapmeet section of the forums.

    MH

LeakDown results- post em up

indydan

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Ouch! For your sake I hope Dan was just throwing numbers out...

He had 3.5% for new, 1.5% for broken in and running strong, 7% junk...

5.5% at 3-400 miles by the numbers given, doesn't bode well. Maybe Dan can clarify.

I guess this is hard to pick a number that works for everyone.

My personal feeling is don't expect great performance without great low leak down numbers.

0 to 2.5 great

2.6 to 5.0 fair

5.1 to 7.5 not good

7.6 and above bad

Dan
 

Prayn4snow

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With the changes to the 2020 Polaris 850, I'm not expecting any problems however I always do a baseline on all my sleds at the beginning of the season. Anyone else do baselines leak down, compression and follow up tests? For those of you that plan some engine mods (or new to motor mods), examples: single, or twin pipes, heads, big bore, turbos etc I would recommend putting some break in miles first. I know many of you semi pro builders know enough about your motors to just mod them from day one. Hoping everyone has a great year on the snow!!

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.
 
Sep 24, 2009
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I guess this is hard to pick a number that works for everyone.

My personal feeling is don't expect great performance without great low leak down numbers.

0 to 2.5 great

2.6 to 5.0 fair

5.1 to 7.5 not good

7.6 and above bad

Dan
I have an SLP leak down tester that only has one gauge. The instructions show quite different results than what's posted here & testing on a couple of used decent running engines also show higher numbers [14 & 18%] Is it just the type of gauge I have? What brand is everyone else using?

The following was taken from the SLP Leak Down Tester instruction sheet:

Cylinder leakage on a new engine or good condition cylinder walls and piston rings should be
within the 5% to 15% range and is best for power. Good service from the engine can be as much
as 25% for average use. Over 25% would be recommended to install new rings and pistons if
needed. Check cylinder for excess clearance, out of round or taper, repair as needed.
 

TRS

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When you get above 5%, it’s a very noticeable change in performance. 2g weight change will not regain consistent rpm. Torque drops off big time at 5% and you will start chasing clutching without improvement. At 9% your 850 feels like a 550.
 
Sep 24, 2009
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When you get above 5%, it’s a very noticeable change in performance. 2g weight change will not regain consistent rpm. Torque drops off big time at 5% and you will start chasing clutching without improvement. At 9% your 850 feels like a 550.
Thanks, I get all of that & I agree. But my tester is a single gauge tester and I believe it's operating at a lower pressure which might be changing the acceptable percentages. I'm hoping that someone experienced with a single gauge tester can confirm that & give some more definitive percentages for that particular type of tester. If not, I'll upgrade to a twin gauge in order to have comparable percentages with everyone else. I'm looking at the OTC tester, any recommendations?
 

TRS

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We have an OTC and Snap-on. Both work great.
Can’t offer any experience on a single gauge.
 

05rmksteve

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I have a OTC and it works great. Could you post a picture of the single gauge tester that you have? Just wondering if there would be a way to add a pressure gauge to it.
 

TRS

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You can google how to make a leak down tester. It will also give you ideas on how to modify your single gauge unit.

05 love your avitar
 

TRS

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That’s a very interesting setup. Wonder which side of the gauge the orifice is on? I would replace the gauge with a better gauge.
It needs a gauge on the regulator to guarantee a100 psi static feed.
 

indydan

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Good to see people getting involved with leak down testing.

As far as numbers go ....and different tester.

The numbers I thru our we're a bit Radom and when I say that I meant exactly that. ( many here bring up good points ) suck as same tester ? What air pressure ? Cold motor , warm motor ? Hot motor ? New sled ? 250 miles , 500 miles, 750 miles 1000 miles.

Let's simplify this....

as far as tester go, we mainly use 2 different ones, ( and we and we constantly cross check them against each other. ( and someone brought up to buy the one that Indydan uses. ). Well here is where I need to explain.

We use an OTC, and a Snap on ...... Then we randomly test the import ones we sell... The import ones have been brought into offer a cheap price which was kinda stupid because they are a little random. ( but we are going to bring in only the OTC Dual gauge one. ) and stick with that. )

But let's just say we have to work with numbers from all different gauges so we can be real about all this.

Trouble shooting two stroke performance motors...... Is complex and if you are infatuated with peak performance then you should leak down test your new sled before you drive it.

Then at 250, 500, 750, 1000, 1500, 2000 and so on ( ball park of thes numbers. )

All that really matters is that either they stay very close to the same with little change from new..

Or...... The test starts out a little on th bad Side because of sub-par cylinder roundness or a below average set of rings ..... Let say 6 percent and the numbers keep getting better as it breaks in let say down to 1-1/2% to 3% and then stabilizes and flattened off.

No mater what guage, what pressure, or what technique if the numbers start to go up the need for a rebuild is coming. Soon

And here is the most important part of of all..... If the pull on the recoil rope starts to get harder and harder over time the motor on its way out.

Why does this happen you ask ? ( trust me your compression test numbers will not being going up..... ) but your leak down numbers will be going up.

What is happening is your rings and or Pistons ( most often both ) are failing and the hard pull on the rope comes from and pressure is going past the rings and pressurizing the crankcase and the motor starts fighting itself so to speak.

Don't be fooled by a great ring seal that is a crisp distinctive snap of the piston going over TDC ...... With great seperation .

Verses a poor overall hard pull that just feels shitty and both cylinders kinda feel somewhat rolled together that lacks separation.

Leak down is the single best ( Motor ) performance trouble shooting test ( period )

Not, clutching and fuel mapping test.


I hope this helps.

Dan
 
Last edited:
Sep 24, 2009
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We use an OTC, and a Snap on ...... Then we randomly test the import ones we sell... The import ones have been brought into offer a cheap price which was kinda stupid because they are a little random. ( but we are going to bring in only the OTC Dual gauge one. ) and stick with that.
I couldn't find any testers on your website. How much is the OTC?
 

BeartoothBaron

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I bought an OTC dual gauge tester off Summit Racing for $80; would be a great bargain if it were the same quality as old school OTC tools, but it's China stuff. Probably better than a no-name off Amazon, but still, I suspect it shows a bit more leakdown than it should. Unfortunately, I don't have another gauge to check it against. Seems like there's quite a bit of variation between cheap testers, probably even from unit to unit from the same manufacturer. Given that, it's probably best to use your gauge to check several known good motors and make the highest reading you see your baseline. https://www.hotrod.com/articles/hrdp-1203-budget-leakdown-testers-tested/
 
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