Polaris RMK 600 - 727 SLP Kit opinions

[Eyelasers]

Hey all,
Looking at the 727 kit for an option in my 07 RMK 600 155. I mainly boondock when I ride, not a lot of high marking and hill climbing, but do it when I need to get from point a to b. I have to say I do not much care about getting the high mark anymore but like to play around and ride hard. I am looking at using this as my primary sled for the 2010 season. I have heard good things about it and would like to hear from the guys that have them or have ridden them.

Thanks for any info.



Anyone have a 727 kit or engine laying around??? Any other 600 HO big bore kit laying around??? Email me at ddecker820@yahoo.com

 

[pura vida]

from what you are describing the 727 would be perfect for you. i have had a 660, 727, and now a 797. each one is faster and noticeably more powerful then the previous. the only issue with the 727 is it uses wisco pistons which you have to be careful to not cold seize. i did it and was surprised how easy it happened. as long as it is always up to temp before you rail on it you should be good. for reliability you can't beat the 660 since it uses stock 700 pistons (from the big block). but as stated, the 727 does have more power. it would be an awesome sled and you would be really happy with it. but... if it were me and i was going to do it again, for the money i would go to the 797 (which does not use wiscos) or if i wanted/needed to stay cheaper i would get a 660 or 685, both of which are significantly less then the 727. i would propably go with the 685 since i've never had one but it is hard to beat the 660 for best value. anyway, more than you were asking but just my experience. enjoy whatever you do.

pv

 

[mountainhorse]

I think that one of the big things that many people overlook is the gyroscopic/initertia effects that the longer strokes have.

In an exact same sled... for example a 155" Polaris RAW RMK.... In a 600, 700 & 800cc powerplant... the 600 will feel much more "nimble" and be able to be thrown around more easily.

This is not because of weight of the sled, but because of mass of the rotating assembly... At 8300 rpm... the difference in stroke and mass of the pistons/rods/crank affect the sled more than you would think.

Heck... even in the 2010 800 Cat with everything else identical to the 2009... you can feel the 4 lb lighter crank in the way she tracks off camber.

Is the 787 a 64mm stroke and 88.5mm piston?

Is this the same piston as used in the 860 kits?

Is this a cast or forged piston?

Does Carl's offer the 787 to the public and what is the cost of the kit?

 

[donbrown]

I think that one of the big things that many people overlook is the gyroscopic/initertia effects that the longer strokes have.

This is not because of weight of the sled, but because of mass of the rotating assembly... At 8300 rpm... the difference in stroke and mass of the pistons/rods/crank affect the sled more than you would think.

Heck... even in the 2010 800 Cat with everything else identical to the 2009... you can feel the 4 lb lighter crank in the way she tracks off camber.

QUOTE]

This is so true.

This is why a balanced clutch is so important.

Also ... the rotational mass goes up as RPM increases and when the sled is shifted this changes and the rotation will "push" back.

The kinetic energy stored in a rotating flywheel is


E = frac{1}{2} I omega^2

where I is the moment of inertia of the mass about the center of rotation and omega (omega) is the angular velocity in radian units. A flywheel is more effective when its inertia is larger, as when its mass is located farther from the center of rotation either due to a more massive rim or due to a larger diameter. Note the similarity of the above formula to the kinetic energy formula E = mv2/2, where linear velocity v is comparable to the rotational velocity, and the mass is comparable to the rotational inertia

 

[mountainhorse]

Uh... yeh.... what he said...

 

[donbrown]

Uh... yeh.... what he said...

Okay go spin a top and hold it top to bottom and rotate it and you will feel the rotational mass conteract your movement.

 

[mountainhorse]

Just playin with ya Don... I dont think I've thought that much since College. LOL

Good alalogy on the top

 

[poorider]

Okay go spin a top and hold it top to bottom and rotate it and you will feel the rotational mass conteract your movement.

that sentence right there sums it up perfectly!

 

[rmk727]

probably can't tell that I have a 727 by my handle but I do, it's an awsome set up, lowend power is such fun, you ride exactly like I do . All my buds that ride d8's and xp 8s comment on the throttle response, Also I could even get more from it by jetting but I'm to lazy to. I've rode it in SD,Black Hills (4to 5000 ft) also in Big Horns (10000) Togwotee 8-11 snowys and Walden Col where we were way up there, had to back off to 3/4 throttle other than that I never changed a thing, it ran with the best of them, you will love it, SLP's clutching sucks thou, I have a good set if you want

 

[polaris dude]

how much does the 727 cost?

 

[rmk727]

SLP gets $2900.00 I have a very good used one includes a case w/waterpump seal installed for $1100.00 u need new gaskets but the rest in 100% condition pm me

 

[pura vida]

also i forgot to mention all of my kits were carls kits and that is the only ones i'd go with. (not to say there are not other good kits out but i know what i'm getting with carl's) also, whatever kit you get make sure you get all the extra's, reeds, pipe, bored carbs, etc. it really completes the package and gets the most of the larger bore.

as far as what MH said above i agree but... there is a noticeable difference in torque with the 797 that i feel is more of an advantage than the hindrance of slightly more rotating mass. it's not like it makes the iq chassis hard to ride. it is still one, if not the easiest sled to ride regardless which of the available motor is in it. the majority of the riding i do is very similar to what the OP described but when you get to a bigger hill you can tell/feel the difference. of course this is just my opinion but it would be hard for me to go back to any of the smaller bores. although it is important to state that the 660 and 727 i had was in a mod edge chassis and the 797 is in an iq. so that obviously makes a huge difference in how the sled performs, more than the motor probably. now with all this said, the 727 is still a rippin motor and woud be awesome in the OP's chassis.

pv

 

[Eyelasers]

Who makes the 797 kit? and is that for the 600HO engine or the 700 CFI engine?

Thanks for all the info and the math lesson. Good INFO!!!!

 

[Ozzimandias]

727 below 200ft

I know that this is a little off topic but I am wondering if I can run a 727 kit at 600-2000 ft elevation. I realize SLP says it is only for higher elevations but is it true or has anyone tried it at lower elevations.

 

[Rob1334]

Was wondering the reasoning behind that too.... thought it might be able to run at lower elevation with bigger jets all around...

 

[pura vida]

carl's makes/made the 797. it is designed for the 600 ho. you have to send them your cases and buy a new crank which cost $1400 just for the crank. expensive but wicked. not sure if they are really offering the 797 much any more b/c they have the 860 now and the price is pretty close to the same. although i'm always a fan of more displacement and power i like that the 797 uses a stock pro x piston and NOT a wisco. not an issue running a 727 at low elevation. i've been doing it for a number of years.

pv

 

[rmk727]

First off my 727 is sold thanks for all the pm's next I'm not sure but believe Carl's makes a 660 not a 727, second the SLP kit doesn't need a crank u use the stock one and in order to run it below 3000 you need to be a fuel mixing guru with race gas and all that

 

[pura vida]

First off my 727 is sold thanks for all the pm's next I'm not sure but believe Carl's makes a 660 not a 727, second the SLP kit doesn't need a crank u use the stock one and in order to run it below 3000 you need to be a fuel mixing guru with race gas and all that

no this is wrong. carl's make a 660, 685, 727, 797, 840, and 860. none of the 727's need a new crank, the 797 needs a new crank. and you do not need a fuel mixing guru to to run below 3000 feet. i rarely run above 3000 and never ran anything but premium pump gas. plus we can only get 90, not even 92, up here. zero detonation issues as long as you get good gas that hasn't been sitting in the tank too long. (read: go to a station that has high volume and sells more gas) as far as SLP v. Carl's, well that is up too you. both are good companies with a long history of excellent products. they both use the same pistons and cylinders, i just feel/perfer carl's porting.

pv

 

[donbrown]

What I have been trying to figure out is how people do this on their own.

I have talked to people about taking a 2004 600 RMK engine and replacing the cylinder pistons with a 700 cylinder pistons.

I already have the SLP 660 pipe can on the sled.

So when I go to "order" or talk to someonme about doing this I am told inconsistant information.

Some say the ECU won't support it, some say the squish is wrong, some say the timing is off by a few degrees.

But the guys who have done this say it is a bolt on and go without grinding the case, or doing any machining.

I have been told by several the head for a 600 and 700 are the same.

Who has put a 700 cylinder pistons on the same year?

 

[McFarckle]

local polaris guy said the 727s are bullet proof.and strong performers!
have also heard that when you bore the carbs out on the 07s you have a bad hesitation on bottom end. just what i have heard

rmk727 please respond to pm