Pro Rmk big bores?

[RKT]

Which/whose kits are you comparing?

Scott,

Not going to name drop withthis thread.. But if it is running an aftermarket cylinder, then the walls are THINNER.. not thicker... Measurements do not lie... Check it out.. you'll see..

Why would one assume that the aftermarket cylinder had thicker skirts?

 

[Scott]

Gotcha, thanks Kelsey.

 

[suitcase]

If you are taking the stock 800 cylinders and boring them out the the 858, How does this make them thicker, than a new cast?

 

[suitcase]

When you get a Carl's 900 your two new cylinders will be the same thickness as a stock motor!

 

[gunnerthesnowman]

Above.. The 900 kit actually has THINNER cylinder walls and skirts than the 858 Kit..
Just wanted to clear that up... Lots of misconceptions on what the aftermarket cylinders actually change in terms of thickness and strength and cooling.....

If you are taking the stock 800 cylinders and boring them out the the 858, How does this make them thicker, than a new cast?

From what I read here , it is saying that if you are running a kit with aftermarket jugs , the cylinder walls and skirts are thinner then the stock Pro ( 2012 ) or (2013) Cylinder wall / skirts after you bore them out to 858cc , that not hard to understand .

Is it true

 

[suitcase]

When you get a Carl's 900 your two new cylinders will be the same thickness as a stock motor!

Carls 900 Cyclinders are the same thickness as stock..12, 13, the skirts are thicker than the 12, they are more like the 13,,,

 

[RKT]

Carls 900 Cyclinders are the same as stock..12 13, the skirts are thicker than the 12, they are more like the 13,,, just got off the phone with the man..

I am not here to argue or put down anybody's kits... But, with all due respect, you are mistaken and I am just trying to clear up and apparent misconception that you are having..

Think about it,,, Your piston has grown considerably, YET, your engine cases are still the same size (outer dimension).. So, where is all this "room" coming from? Besides I have seen it first hand.. But, again, I just prefer to leave it at rest rather than start a debate..

You can not magically add material in the case..an dyou can only remove so much before you run into issues. and the 800 cases are VERY small..

In fact, grab a base gasket... add the piston dimension difference to the gasket, then see what you have left. You'll get the idea from doing that...

Anybody got any pics of there engine and the cylinders?

 

[suitcase]

[



My case is not the same as stock, it is ported to not only fit the larger cylinders, but to allow for the skirts to stay as close to stock thickness as possible.

For example if you have a 10mm block, and bore a 4mm hole into it you have 6mm's of meat left.
If you start with a 14mm block, and bore a 6mm hole into it you have 8mm's of meat left.

With new cast cylinders you can have thicker walls in the cylinder, also allowing you to have a thicker skirt after making room in the case.

When Boring out stock cylinders, you are making things thinner than stock no matter how you look at it.

Im not saying your kits don't work, but from what I have seen with boring stock 800 cylinders, you can run into brakage in the exaust ports because of the lack of material there after boring.
Its not my choice when it comes to my motor.

Im sure you have a good kit its just not for me, and what I ask out of a motor.
Your kit has a good Rep. Im sure you will continue to do so. Maybe one day I will have the pleasure of running into a RK Tec motor, so I can see for myself.

Thank you for your input..

 

[RKT]

[



My case is not the same as stock, it is ported to not only fit the larger cylinders, but to allow for the skirts to stay as close to stock thickness as possible.

For example if you have a 10mm block, and bore a 4mm hole into it you have 6mm's of meat left.
If you start with a 14mm block, and bore a 6mm hole into it you have 8mm's of meat left.

With new cast cylinders you can have thicker walls in the cylinder, also allowing you to have a thicker skirt after making room in the case.

When Boring out stock cylinders, you are making things thinner than stock no matter how you look at it.

Im not saying your kits don't work, but from what I have seen with boring stock 800 cylinders, you can run into brakage in the exaust ports because of the lack of material there after boring.
Its not my choice when it comes to my motor.

Im sure you have a good kit its just not for me, and what I ask out of a motor.
Your kit has a good Rep. Im sure you will continue to do so. Maybe one day I will have the pleasure of running into a RK Tec motor, so I can see for myself.

Thank you for your input..

Suitecase

Again.. Will ALL due respect, I have seen the cylinders... AND you are forgetting one factor, THE PISTON IS ALSO MUCH LARGER!

So take your same anaolgy and then change you 6mm reference to reflect the LARGER PISTON. With your example, you are NOT accounting for the larger piston diameter.

Again, I really to not want to start a huge debate on this..I am sure the kits are fine kits. I have seen the cylinders and know about thicknesses.. They are what they are, not saying it is a bad thing, just a thing..

Maybe if you get your cylinder off sometime, you can take some measurements and see for yourself

Take care

 

[die hard poo]

Another thing that the new single cylinders with a big bore (either the Carls or PAR kit) that interest me is the much better cooling around the cylinder and more meat around the exhaust valve/port to allow for better cooling there too. Maybe this aids in the big bore reliability too... Just thoughts, not FACTS...

 

[minecat]

RKT is right about the 900 beeing thinner than a stock 2012 800 poo pro, my 900 is . .221 thick a stock 2012 is .234 thick. just measured them both

 

[RKT]

RKT is right about the 900 beeing thinner than a stock 2012 800 poo pro, my 900 is . .221 thick a stock 2012 is .234 thick. just measured them both

Just for reference my 2012 cylinder measures .241"

 

[zr600]

Wow cool videos you have of the proclimb with jaws pipe, and of the 858 bb. How did the 858 pro do against the 900 bdx proclimb? So with the 858 you just throw on the new cylinders, head, pistons, clutching, and a boondocker box with no other mods, or do you recomend any other mods to make the kit work better? No differenct pipe will make more power or intake?

 

[minecat]

Interesting on your measurement Kelsy. I went out and measured my 800 skirts again and the mag side is .234 and the PTO side is .230 nice to see that polaris has concistancy NOT!! curious as to what your 858 skirts measure out to.

 

[suitcase]

Well heck I guess im just to stupid! I think it is great that you can bore a cylinder and still have the thickness incress! I have the 12 and the 13 cylinders in hand, HMMMM!! ?? something is not adding up..
Im just a rider, have no finacial ties to anyone. and I know what I buy when lay the cash down..

Good luck I wish you all the best..

 

[1200psi]

Well heck I guess im just to stupid! I think it is great that you can bore a cylinder and still have the thickness incress! I have the 12 and the 13 cylinders in hand, HMMMM!! ?? something is not adding up..
Im just a rider, have no finacial ties to anyone. and I know what I buy when lay the cash down..

Good luck I wish you all the best..

Suitcase you are not stupid !You are 100 % correct just to clarify Kelsey . PAR or Carls cylinders have a .243 intake skirt thickness. By my math your 2012 has a sleeve diameter of 96.8mm stock inside is 85mm so you have a 11.8 mm /2 gives you .467 /2 is .234 on your STOCK thickness . Now you bore to 88 mm loose 3mm .118/2 .058 Your cylinder with your bb has a sleeve thickness of .176 thou for your sleeve so correct me if I am wrong.


Brad

 

[suitcase]

Now those are numbers that add up..

 

[RKT]

I guess there MAY be some misconception on what is getting measured..

There is the protruding sleeve that hangs below the cylinder base and then there is the actual wall thickness present at the transfer port inner wall.. These two, different, areas can be very different in thickness (just the the OEM's are different in these 2 areas)

So, you can have a very thick or thin lower skirt area but this does not necessarily tell you anything about the inner transfer wall thickness...

 

[live2beel]

Anymore info on these big bores?

 

[suitcase]

Anymore info on these big bores?

http://www.snowestonline.com/forum/showthread.php?p=3257801#post3257801