PrayN4snow's Stage build/tuning the AXYS RMK 800

CO Powder · Oct 17, 2015

What is the reasoning for fitting a durability kit to a supposedly much improved engine?

So far it is just a pipe/can modification, stock engine still?

drjcat · Oct 24, 2015

Hooray for you,

Well written and very informative IMHO. I am interested in your findings with your stages on the new Axys as I myself did similar build on a 2013 pro rmk. I installed a MTNTEK piston fix kit,Starting Line pipe and Silencer,Mapped controller,Power Addiction Head,ZBros 36" Front Arms,Front Fox Shocks, Ice Age Promotion arm,MDS Clutching,3" Track,7 tooth drivers, All in stages like yourself and I must say that I am honestly very pleased with the "real world" results with what I have done.It is far and away better and quicker than any stocker I have been up against. Im holding off on the new Axys until 2017 as my pro has never had so much as a hiccup and never let me down once so I will be looking for similiar mods for my new Axys next year. Myself like you and many other 50+ year old modders just love to tinker, Sometimes successful and sometimes.. Well lol.Good luck ! I will be very interested in your findings.

Bikeman Performance Plus · Oct 26, 2015

Great thread Prayn4snow! We are excited for this build as we believe our products for the Axys are some of our best work yet. Robert came to me like any other customer asking about product information... then we started chatting about the forums and doing a build where he could document and be here for the dyno stages, then give real world experiences. We thought it would be a great idea as it's hard for us to be on the forums as often as we'd like. I'm a consumer just as much as the rest of you and I know the results coming from someone like Prayn4snow mean a lot more than what the companies claim.

Right now we are just waiting for some cooler weather so the dyno shows more accurate winter like conditions.

CO Powder said:
What is the reasoning for fitting a durability kit to a supposedly much improved engine?

So far it is just a pipe/can modification, stock engine still?

Much improved might be a little far fetched. Improved, yes... but still not where it should be. They still have the same short pistons and after just 400 miles on our short track last year we already saw significant wear on the intake side of the piston like on the old motors. This motor has a lightweight crank, different porting (almost identical to our porting for the 800CFI), and pistons with oil retention grooves in them. Of course the addition of an electronic oil pump does help things if you are the rider most of us here are. For those cruising trails and not in the throttle all day, the oil mixture is very lean. Up top they are at 35:1 which is not bad at all especially when running a good synthetic.

More of the story.... engine life will be improved, but you will still see a loss of compression earlier than on many of the competitions motors. No motor is exactly the same, so just keep an eye on your static compression(as you should with any 2 stroke).

The durability kit however is a performance upgrade even on a brand new stock motor. It provides a better angle for the reed cage to enter the bottom end, and adds much needed crank case volume. This results in +5hp on the Axys platform plus provides an even better top end. The durability kit also allows this motor to rev higher. So in our stage 3 kit with the bully dog, we can run the motor at 8400-8500 and they simply scream.

-Mike

Prayn4snow · Nov 19, 2015

Back to the Build! Im sorry Ive been off of Snowest for a while, sometimes life gets in the way of pleasure. We have also been waiting for cool weather to start the dyno runs for more accurate results. Im hoping these stages will be done soon. Thanks for the patience. Here is the break in video, its pretty neat how the system can vary that load and rpm for a better break in. Once broke in, we will do a base line dyno then each stage. Ill post things as I can. Thanks.

Prayn4snow · Nov 19, 2015

Ok, like I said, I'm not the best with computers. I can't get the video to load. I also asked them to come up with a lite weight battery box to replace the steel factory one. They did an excellent job on this and it fits the extremely lite weight battery they carry! Ill get the exact weight savings but it should be around another 10 pound savings!! Pretty soon we will have to add weight just to keep it from floating off lol.

trdehmer · Nov 19, 2015

I do like that battery........I just hope it works in the severe cold! My last lithium left me stranded!

Prayn4snow · Nov 20, 2015

trdehmer said:
I do like that battery........I just hope it works in the severe cold! My last lithium left me stranded!

This battery has 336 cold cranking amps's so it should work great on our two-stroke Sleds. This is more than the factory lead acid battery. For the price per pound this is the cheapest weight-loss you can make on the sled if you have electric start or the battery because you have the interactive display.

Ive now tested the battery in January and it was working fine all day at 8-12 degrees outside all day. Plus I have the pull rope back up unlike the 4 strokes.

Top · Nov 20, 2015

Prayn4snow said:
This battery has 336 cold cranking amps's so it should work great on our two-stroke Sleds. This is more than the factory lead acid battery. For the price per pound this is the cheapest weight-loss you can make on the sled if you have electric start or the battery because you have the interactive display.

If that is a WPS battery they do work "okay" in cold weather. I have one on my KTM 300.

turboless terry · Nov 20, 2015

trdehmer said:
I do like that battery........I just hope it works in the severe cold! My last lithium left me stranded!

It is a no Brainer on the axys. It can't leave you stranded because you have a pull rope. Even if you have to pull start it one time in the morning you will be good the rest of the day. I ordered a kit for me and my wife.

sledheader · Nov 20, 2015

Why is it a big deal to pull a rope these days? Especially with fuel injection. Max 3 pulls on a cold start...really? Not judging, just don't get why you would want the extra weight to avoid one pull starts.

turboless terry · Nov 20, 2015

I have cranky shoulders from doing Concrete for 25 years. If you worked a day with my shoulders you wouldn't even question it. The other thing is if you figured how many times you start and stop every ride I believe it will make a slight difference at the end of the day. A buddy and I were both stuck. We rolled them over and it was a huge struggle to get back on your sled. I just hit the es on mine. He had to really struggle because of the awkward angle with his sled on a steep side Hill and facing down hill and on its side. You had to be on the sled to start it because the snow was so deep or you were up to almost your chest. I bet I watched him struggle for almost a minute. Which do you think burned more energy? That fiasco or riding a sled around all day with, I'm guessing, 8 to 10 more pounds since I ordered the bikeman kit. A normal start and stop doesn't take much but the es was priceless in that situation. We get in that situation a lot when it is deep. I don't know how the axys is but the pro always started on the last 8 inches of the rope. That motion disagrees with my shoulders. The etecs only take like a half pull. That isn't as bad.

Prayn4snow · Nov 20, 2015

This was a very exciting day for sure! The stock dyno was 157 hp. I will post up a graph once I get home on my computer. We dyno'ed each stage and recorded the horsepower and torque we are done with stage III and everything is very impressive. With the stage III we averaged 177 hp and we hit a peek of 180 hp a couple times! It looks like Polaris has a homerun this year with the axis 800 HO. They did leave some power on the table but I think it was on purpose because they have to keep everything withIn specs because of emissions requirements.

Prayn4snow · Nov 20, 2015

Bikeman performance parts really bring out the hidden horsepower and torque in this motor. It doesn't look like it was easy for them to do because they went through a lot of research and development for each stage. Nothing was left unchecked if they thought they could improve on it they tried different variations until they were happy with the results. I am impressed with how hard it pulls from 7500 up to the peak ( The peak depends on which stage you have). Again I will post up some graphs of each stage once I am home.

Prayn4snow · Nov 21, 2015

Here is some more pics of this weeks dyno time. I can't get my scanner to work for the dyno sheets. I may have to wait until Monday and see if their shop can post them.
1st pic is the motor hooked to the dyno. (directly to crank shaft)
2nd is the new lite weight battery box bolted in.
3rd is getting ready to bolt BMP billet "low alt" head on.
4th is dif between stock head with there spark plug bung sticking way into the dome compared to BMP smooth dome.
5th is close up of stock dome after break in and stock dyno pulls.

Davajn · Nov 22, 2015

Prayn4snow said:
Here is some more pics of this weeks dyno time. I can't get my scanner to work for the dyno sheets. I may have to wait until Monday and see if their shop can post them.
1st pic is the motor hooked to the dyno. (directly to crank shaft)
2nd is the new lite weight battery box bolted in.
3rd is getting ready to bolt BMP billet "low alt" head on.
4th is dif between stock head with there spark plug bung sticking way into the dome compared to BMP smooth dome.
5th is close up of stock dome after break in and stock dyno pulls.

Nice thread Prayn4snow. You actually got me a little curious about the bmp stages so i might have to contact them

You are doing a can ontop of the stage3 kit? If so does it add anything to the hp/trq and is it the bigger can you went with?
Have you heard their velocity can compared to a stock? Does the soundlvl stay somewhat near stock?

Prayn4snow · Nov 22, 2015

Davajn said:
Nice thread Prayn4snow. You actually got me a little curious about the bmp stages so i might have to contact them

You are doing a can ontop of the stage3 kit? If so does it add anything to the hp/trq and is it the bigger can you went with?
Have you heard their velocity can compared to a stock? Does the soundlvl stay somewhat near stock?

Yes, Im running the larger can. It is close to stock sound at idle and mid range, however it is louder wide open but not much. Sounds nice, with a throaty sound. Lots of people heard it running at Haydays with the pipe and this can. I don't care for loud cans, but the small one they have does sound really good Im just to old I guess lol. Im sure it will appeal to some depending on where you live and it is a larger weight savings. They have a sound DB meter, but we didn't get it outside away from the buildings and off the concrete. Id like to have some snow on the ground to know exactly how loud it is. I might buy one myself from Amazon because Im back home now. It did pick up some HP by it self, but the bigger gains were with the pipe and of course even more with the next stages.

Prayn4snow · Nov 22, 2015

some more pics
1st is the new BMP lite weight battery box on the scale at 0.55lbs Part #: BMP-AXYSBATTBOX
2nd is stock battery box at 1.75lbs and its steel that holds the heat a long time if your going to change out a quick drive belt. You have to sit and let it cool awhile. The BMP aluminum one dissipates the heat and I would think should help belt life as well?
3rd is the BMP lite weight battery from WPS. it has a power meter on top and is 360CCA which is more than the stock battery and only weighs 2.35lbs!!! This is the cheapest weight savings on your sled.
4th is the battery and BMP lite box at 2.9lbs. Part #: BMP-AXYSBATTKIT
5th is the stock battery and box at 14.90 lbs thats as much as my bowling ball! The stock battery is a 270CCA.

Prayn4snow · Nov 22, 2015

Still more pics
1st is the stock pistons after running the break in and stock dyno pulls. They are better than last years, however they were already showing some ware on the lower oil groves.
2nd is the stock motor torn down for inspection and to add the BMP durability kit with new pistons, rings, gaskets, base plate and longer cylinder bolts.
3rd is what I would recommend using to get the power valves off without using some unapproved forum words.
4th is the new polaris exhaust valves that they say never need to be cleaned. This is using fresh 91 non eth premium and Polaris VES Gold oil for break in and stock dyno pulls.
5th is better pic of stock Axys exhaust valves after just break in.
6th is a kicked in the gut feel of having your brand new sled that hasn't seen snow torn apart to see what makes it tick

If your as strange as me, your ok with making a FrankenAxys ! Now Im just "PrayN4snow"!!

Prayn4snow · Nov 22, 2015

More pics of install.
1st is stage 1 with BMP Pipe and Can
2nd is Can and lite weight battery box close up
3rd is getting ready for stage 2
4th stock head removed ready for BMP head
5th is stock head on bench next to BMP Billet head and low alt domes
6th close up of stock head after just break in with fresh 91 non ethanol premium and VES oil.
7th close up of BMP head with low alt domes
8th top of BMP head
9th BMP Pipe, Can and Billet head installed

Scott · Nov 23, 2015

sledheader said:
Why is it a big deal to pull a rope these days?

It's not...if you have healthy shoulders.

I've been a REALLY healthy and injury free person my whole life. I kick azz.

The last couple of seasons, I've developed an impingement in the front of my right shoulder and by the end of the day I am almost riding out left-handed.
It's a torn bicep tendon or something like that. It hurts like a mofo.
Pulling the rope? HAHA, that's a fun one. I'd rather leave my sled running some days.

Some days, I can't do push-ups without some pretty sharp pain in the right shoulder.

Electric start? Yeah, I'll take one.

PrayN4snow's Stage build/tuning the AXYS RMK 800

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