Since you are so thrilled with them, wanna buy a new take out set? So what are the measurements on yours?
How many miles on your aftermarket pistons in CFI-2 engine?
- Thread starter Murph
- Start date
Since you are so thrilled with them, wanna buy a new take out set? So what are the measurements on yours?
I have about a thousand miles on my mtk piston kit, still sounds quiet unlike the clacking stock pistons at 1500 miles ,,so ,,,,,WOW got almot 2500 miles now,, oops shouldnt of said that!!! Nock on wood! If it brakes Il put it in the trailer and ride the snow donky!
come to think of it ,I think Ill just ride the donky!
come to think of it ,I think Ill just ride the donky!Murph I hear a LOT of guys saying that their rings are flaking. Almost universal when there are other problems. With the excessive blow like you have does that cook the oil and cause more wear? Are the aftermarket rings better? Would just a set of really good rings fix anything on a new or undamaged engine? Pistons are cheap but rings are really cheap.
A
assault11
Well-known member
I didn't measure them. I sold the whole motor. Just dropped Carl's 900 in, heading out to break it in tomorrow
Matt, normally if you see flaking on the rings..its moisture(snow/water) coming thru the intake...very common on sleds....we used to see it on our mudders if they injested very much.....wheres the flaking?(predominately intake side?)...
Mike, I agree with you on snow ingestion being a likely culprit but I think there is more going on with the ring flaking issue. I've pulled apart a fair amount of Dragon motors and only a few of the Pro's but the ring flaking is way more predominant in the CFI-2.
Unless the manufacturer changed on the rings, then it's the same ring(s) that were used in the CFI-4. It makes me wonder about the fueling (2 injector) as well. It will be interesting to see if the ring issue goes away with aftermarket piston kits.
I think we can all agree that the airbox sealing aspect of the Pro is way better than the Dragon, unless there is something I am missing.
Remember siliconing headlights to hoods?
Very true Dave, but I think the Pro is pulling moisture thru the prefilters(just some obeservations from mine when I first got it out in deep snow that I havent seen again since adding a flowrite to the upper airbox), and it may well be a fuel/heat related issue causing it as well....(although I would think it would be more spread out on the rings instead of just the intake/boost ports...
That is very hard to come by & when it does appear on the forums from time to time, it's easily missed!
MTNTK FIX KIT FOR THE 08-10 DRAGON 11-12 Pro FIX KIT
We have sold over 3000 of MTNTK's Fix kit in the US and in Canada for MTNTK. Ron at High mark Rentals in West Yellowstone Montana put them in all his rentals and has put on over 2500 to 3500 miles on Polaris 800 CFI motors since the install of the MTNTK's Fix kit, Before the install of the FIX KIT they were having major burn down issues with the Motors going down every weekend, and he was out the income of the rental and the rebuild, after the install of the Fix kit Ron has said he actually made money of the last few years.
Hope this info helps
We have sold over 3000 of MTNTK's Fix kit in the US and in Canada for MTNTK. Ron at High mark Rentals in West Yellowstone Montana put them in all his rentals and has put on over 2500 to 3500 miles on Polaris 800 CFI motors since the install of the MTNTK's Fix kit, Before the install of the FIX KIT they were having major burn down issues with the Motors going down every weekend, and he was out the income of the rental and the rebuild, after the install of the Fix kit Ron has said he actually made money of the last few years.
Hope this info helps
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I know Ron very well! He did install these kits in his rentals. He started to put them in the dragons. They ran much better and sounded 100% better. Last winter he installed these kits in everyone of the 2012 pros that went down. He has 4000-5000 miles on these kits with NO problems. Very good product
That funny we've bought 2 pros from Ron and he never mentioned anything about a mtntk's kit. said the pros have given him no problems. Are you talking pro cfi2 or dragon cfi4?
Murph, I'm afraid you may not get much of the hard data you're really looking for. Many of the 800 CFI-2's have been under warranty up until now so going aftermarket really hasn't been necessary. The 2011's which is the first year of the CFI-2 motor, just ended with their 2nd year of engine warranty. There aren't very many people that have decided to void their warranties and go with aftermarket kits. I do know of 2 because I voided their's for them.
I don't need to recommend the product I use as you asked for that not to happen, but I can tell you the difference between this product and stock has been phenominal. And it's because of this, I've felt no need to tear it back down for measurements. I've removed Y-pipe and Exhaust valaves a few times while running this kit and everything looks perfect. The other kits (same kit) I've installed have been the same.
Prior to going aftermarket in the Dragon motor, I was probably one of the last people to believe that there was an issue with the 800 CFI. I was drinking the Polaris cool-aid thinking that the issues were everything but the internals. But after cracking a cylinder skirt with 350 miles while running a turned up oiler and extra oil in the tank, (24:1)
fuel controller for better tuning, religiously warming up motor everytime, Air tight sealed airbox and intake system, I realized it is more luck of the draw and how close (or not) the tolerances were at manufacturing.
My '12 Pro is getting this same kit after 300 miles. The side loading on the pistons is fixed with a shim and redsigned piston which does address THE issue in this motor. And it really is amazing when you HEAR how much quieter the motor is after said kit is installed not to mention the extra performance.
As I side note, I ran into Ron at High Mark in a motel parking lot last summer and everything that is stated in this thread is exactly what he said to me when we were discussing the 800 CFI 2 and 4.
I don't need to recommend the product I use as you asked for that not to happen, but I can tell you the difference between this product and stock has been phenominal. And it's because of this, I've felt no need to tear it back down for measurements. I've removed Y-pipe and Exhaust valaves a few times while running this kit and everything looks perfect. The other kits (same kit) I've installed have been the same.
Prior to going aftermarket in the Dragon motor, I was probably one of the last people to believe that there was an issue with the 800 CFI. I was drinking the Polaris cool-aid thinking that the issues were everything but the internals. But after cracking a cylinder skirt with 350 miles while running a turned up oiler and extra oil in the tank, (24:1)
fuel controller for better tuning, religiously warming up motor everytime, Air tight sealed airbox and intake system, I realized it is more luck of the draw and how close (or not) the tolerances were at manufacturing.
My '12 Pro is getting this same kit after 300 miles. The side loading on the pistons is fixed with a shim and redsigned piston which does address THE issue in this motor. And it really is amazing when you HEAR how much quieter the motor is after said kit is installed not to mention the extra performance.
As I side note, I ran into Ron at High Mark in a motel parking lot last summer and everything that is stated in this thread is exactly what he said to me when we were discussing the 800 CFI 2 and 4.
DD-- I agree with you that a lot of empirical data may not be out there...yet. My hope is that this thread will be like the motor failure thread in the IQ section.
To clarify, I think it is great if CONSUMERS or installers tell us what kit they are running-- I was hoping to avoid mindless cheerleading based on the purchase of a particular kit versus the performance of said kit. Part of the point of this thread is to see exactly how the numerous kits perform with mileage. So that others may make an informed decision on which kit to purchase based on real world results-- not marketing hype. I think it would be helpful if we knew what kits you installed and the extended performance you have witnessed. With the kits you installed with the CFI-4 motors, what is the mileage interval that you have been replacing pistons at? ( kit piston replaced by kit piston?)
All I wish to avoid is the brand bashing of kits that others chose not to buy.
I have done the same as you and checked my stock pistons on all three of our Pros every time I do the valves. So far, no scuffs, no noticeable wear. On my 2500 mile 2011, I finally took off the cylinders and they also look great and the intake side rings look good. I still need to check the bore and the piston measurements and also run a hone through the cylinder to see if any cracks show up but nothing visible so far. Curious if the injector placement is really a problem with the CF1-2 motor or if the cases of flaking rings is something else-- bad supplier, snow injestion, or ???
Thanks for your input.
To clarify, I think it is great if CONSUMERS or installers tell us what kit they are running-- I was hoping to avoid mindless cheerleading based on the purchase of a particular kit versus the performance of said kit. Part of the point of this thread is to see exactly how the numerous kits perform with mileage. So that others may make an informed decision on which kit to purchase based on real world results-- not marketing hype. I think it would be helpful if we knew what kits you installed and the extended performance you have witnessed. With the kits you installed with the CFI-4 motors, what is the mileage interval that you have been replacing pistons at? ( kit piston replaced by kit piston?)
All I wish to avoid is the brand bashing of kits that others chose not to buy.
I have done the same as you and checked my stock pistons on all three of our Pros every time I do the valves. So far, no scuffs, no noticeable wear. On my 2500 mile 2011, I finally took off the cylinders and they also look great and the intake side rings look good. I still need to check the bore and the piston measurements and also run a hone through the cylinder to see if any cracks show up but nothing visible so far. Curious if the injector placement is really a problem with the CF1-2 motor or if the cases of flaking rings is something else-- bad supplier, snow injestion, or ???
Thanks for your input.
So diamonddave. Im curious as to which kit you ran. Can PM me if youd like.
Empirical data:
Sorry for the delay.
2011 ProRMK 155 ES
Ride 6-9000', deep heavy Tahoe snow, avoid trails, 2,500+ HARD miles.
All original motor still running fine, just seemed tired, wanted to freshen up.
At sea level, compression was 110 PSI in both cylinders
2500+ miles, no cylinder scarring, cross hatch still visible. Before and after honing-- no cracks visible
Pulled original stock pistons--measured out at 3.3385" PTO, 3.3388" MAG
Cylinders PTO 3.3465" and round. MAG 3.3465" and round at top and middle
Cylinders PTO 3.3469 and round MAG 3.3470" and round at bottom
Cylinder Taper .0004" PTO .0005" MAG (service limit .002")
New OEM Polaris (gasp!) pistons measured the same at 3.3415"
Original 2500 mile pistons collapsed .003" IF they were the same size as current pistons.
New installed pistons will have piston to wall clearance .005". Polaris manual spec is .004-.0055" (service limit is .009")
As a comparison, pics of SkiBreeze OEM pistons and RKT pistons-- with measurements:
Sorry for the delay.
2011 ProRMK 155 ES
Ride 6-9000', deep heavy Tahoe snow, avoid trails, 2,500+ HARD miles.
All original motor still running fine, just seemed tired, wanted to freshen up.
At sea level, compression was 110 PSI in both cylinders
2500+ miles, no cylinder scarring, cross hatch still visible. Before and after honing-- no cracks visible
Pulled original stock pistons--measured out at 3.3385" PTO, 3.3388" MAG
Cylinders PTO 3.3465" and round. MAG 3.3465" and round at top and middle
Cylinders PTO 3.3469 and round MAG 3.3470" and round at bottom
Cylinder Taper .0004" PTO .0005" MAG (service limit .002")
New OEM Polaris (gasp!) pistons measured the same at 3.3415"
Original 2500 mile pistons collapsed .003" IF they were the same size as current pistons.
New installed pistons will have piston to wall clearance .005". Polaris manual spec is .004-.0055" (service limit is .009")
As a comparison, pics of SkiBreeze OEM pistons and RKT pistons-- with measurements:
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I have been running the Fix Kit's from MTNTK. I contacted another builder 3-4 days ago because I have a person that wants his kit and he never repsonded.
DD- Thanks for the info. Keep the reports and data coming from MTNTK fix kits as the miles rack up (when/if you see some of those sleds again)
Also, thanks for NOT taking the opportunity to bash a non responsive piston kit vendor.
