My RKT 858 experience

[winter brew]

So the bottom end failed on a relatively high mileage engine after doing a top end BB which doesn't appear to be related to the failure?? But before the crank failed it ran strong. ??
What am I missing here....rebuild the bottom end, put it back together and run 'er. ???

 

[pura vida]

...I refuse to get dragged into ANY sort of thread decline and public forum BS.. (please see my earlier post).

really kelsey?? since when? should we go dig up some of your other posts in other threads? maybe you don't intend to come off so harsh, but you do, and on a regular basis.

again, i didn't first read this thread as an attack on you in anyway. actually it was the opposite, talking about the impressive initial impressions and the potential this motor showed. i don't think anyone said or indicated there was a massive engine failure, simply a significant loss of power which led to further investigation.

pv

 

[Seabass152]

So the bottom end failed on a relatively high mileage engine after doing a top end BB which doesn't appear to be related to the failure?? But before the crank failed it ran strong. ??
What am I missing here....rebuild the bottom end, put it back together and run 'er. ???

Well, just that Kelsey's neighbor saw Bigfoot, the rule of 10's when telling a story, don't ask a relevent question about this motor unless you want to be scolded and that the internet forums are pure evil and full of lies. Unless of course you are using these forums to sell a new aftermarket product to us that claims to fix all our problems. In a nut shell.

 

[RKT]

really kelsey?? since when? should we go dig up some of your other posts in other threads? maybe you don't intend to come off so harsh, but you do, and on a regular basis.

again, i didn't first read this thread as an attack on you in anyway. actually it was the opposite, talking about the impressive initial impressions and the potential this motor showed. i don't think anyone said or indicated there was a massive engine failure, simply a significant loss of power which led to further investigation.

pv

PV... If I come off harsh, then that is unfortunate. because it is never my intent.. Kinda te nature of text vs. voice communication..

Not sure what you mean by "digging up" other posts of mine.. While I can not remember all of my posts from the last year or so, I TRY and really try to keep ALL my responses 100% factual and direct to the point.. So, if that is a definition of "harsh" then I guess I am guilty.. But IMO, keeping things factual and on topic doe snot equal harsh.. I am a VERY lousy typer... Very lousy.. so, I keep thing short and to the point... No hidden meanings or subliminal writings.. just short, to the point, responses, largely based on my very lousy typing abilities.. So, please do not think it is related to any other than my lack of typing skills...

as for who sated it was a massive failure.. I looked back, because I did not remember exactly what was said or WHO said it(and this is not going to help me any) but it turns out the word massive was not used.. my apologies.. Ya see I am guilty of improvising just like everybody else.. the word "completely wasted" and "incredibly bad" was used.. and here is where I REALLY wish this wasn't the case.. but it was posted by you. LOL...

i saw both the cylinders and pistons. luckily i'm uninformed enough i don't have the ability to know or relate proprietary piston or porting design...

but i've built, blown up, and rebuilt plenty of motors and these pistons and cylinders looked incredibly bad. completely wasted. and they felt just as bad as they looked. i've seized motors before that looked better than these cylinders and pistons looked. my first comment was, "good lord, those look worse than pistons out of a bad cfi-4 800 motor".

there was clearly a motor issue. what that issue/s was i'll let those with more expertise and experience than me to figure out. it's a bummer b/c it showed some tremendous potential at first and was quite impressive. but later on, after watching it have its *** handed to it by stock sleds, it was clear something wasn't copacetic. and the pictures clearly show that...

hopefully kelsey (sp?) gets it worked out. could be a really nice setup.

pv

PV, I really am not trying to come off as harsh and I am not pointng fingers since I really did not look back to see who typed the response.I just remembered it and summarized it..

Hopefully no hard feelings??

In all honesty, when you type as poorly as I do, it is hard to get things across and conveyed in their true light

 

[RKT]

Well, just that Kelsey's neighbor saw Bigfoot, the rule of 10's when telling a story, don't ask a relevent question about this motor unless you want to be scolded and that the internet forums are pure evil and full of lies. Unless of course you are using these forums to sell a new aftermarket product to us that claims to fix all our problems. In a nut shell.

LMAO... Good one!

 

[AKSNOWRIDER]

Kelsey, the motor does have a skirt loading issue..been proven time and again(both piston and cylinder skirts breaking)..now in most motors would this be an issue..most likely not..but due to a pretty thin cylinder, piston design, case deck height and what I think is the most important issue...low oil into this motor stock(especially when you consider the injectors spray oil less fuel right at the intake piston), they combine to cause skirt issues...while its design rod ratio is considered long..if it was made longer..it would take the loads off both the piston and skirts...and most likely improve breathing which should add HP...so yes, long rod combo does seem like a true fix..can just a piston fix these issues? maybe..but tightening the bore with the coolant system on this motor is risky..and there is a good chance a person could squeak a piston.. and over time there is no telling if a tighter bore alleviates enough loading to stop it from breaking the cylinder skirt..carls kit from what info I have gathered fixes both issues with piston and cylinders(cylinders do have a thicker sleeve then stock...)..anyway..those are my concerns with a piston "kit" weather stock bore or big bore vrs a connecting rod"kit" ...and why I am more looking toward a BB vrs a turbo...

 

[hyperduc]

I too thought that it was rather cute that the guy selling a fix it kit would be the first one to dismiss any potential issues with his kit as unfounded rubbish and speculation from liars.

 

[pura vida]

it wasn't unfortunate that i was the one that posted the cylinders and pistons were wasted, they were, they are. now, i, in no way have the motor building experience that you or many others do on this forum but i do know when i see and feel cylinders that need replated and pistons that need replaced.

i will definitely agree with you on the difficulty of accurately presenting tone and intention on the internet vs. over the phone, or even better yet, in person.

pv

 

[RKT]

Kelsey, the motor does have a skirt loading issue..been proven time and again(both piston and cylinder skirts breaking)..now in most motors would this be an issue..most likely not..but due to a pretty thin cylinder, piston design, case deck height and what I think is the most important issue...low oil into this motor stock(especially when you consider the injectors spray oil less fuel right at the intake piston), they combine to cause skirt issues...while its design rod ratio is considered long..if it was made longer..it would take the loads off both the piston and skirts...and most likely improve breathing which should add HP...so yes, long rod combo does seem like a true fix..can just a piston fix these issues? maybe..but tightening the bore with the coolant system on this motor is risky..and there is a good chance a person could squeak a piston.. and over time there is no telling if a tighter bore alleviates enough loading to stop it from breaking the cylinder skirt..carls kit from what info I have gathered fixes both issues with piston and cylinders(cylinders do have a thicker sleeve then stock...)..anyway..those are my concerns with a piston "kit" weather stock bore or big bore vrs a connecting rod"kit" ...and why I am more looking toward a BB vrs a turbo...

AK, no doubt a longer rod will lessen side load... but lessening the side load and stating that there is a side load issue are 2 different things and ,it appears, that they have been lumped into the same "problem area"..

Just because something can be improved up (rod ratio)does not mean that the current set up is problematic or flawed.. agreed? so to state that there is a side load problem is questionable..

The Cat has a lesser rod/ratio (same bore and stroke and a heavier piston)) yet has no skirt or piston failures as a result.. so, this would make a good case for the rod ratio being fine.. agreed?

You MAY rspond with " Yes, but the cat cylinder skirt walls are thicker" which would be correct.. so, does this mean that Cat does have a rod/ratio problem and the thicker skirts are masking it?
OR does it mean that there is no rod ratio concern and that the issues are piston and cylinder related (Polaris) and NOT a result of the rod ratio?

If the latter is the case, then the problem is NOT rod/ratio but piston and cylinder related.. I can fix the piston issue (and do) but the cylinder issue would require case and cylinder modifications which, I feel, is out of the feasible price range and work for the consumer.

So, what are your thoughts on the above??

I will also mention that BRP has even a lesser rod ratio then Polaris or Cat and they never break skirts either..and that the 858 with thinner skirt walls, has not broken a skirt on the piston or the cylinder.

Thoughts?

 

[AKSNOWRIDER]

Kelsey, pretty hard to compare the cfi motor with either of the other brands..just a totally differnt design.but with that said..yes the suzuki motor has same this, same that..but..it doesnt have an issue with cylinder loading..we both agree on that...why? easy..tighter piston clearence..and thicker cylinder sleeve....if you punch a cat out to the same wall thickness of the poo and build a piston at what polaris calls for specs are you sure it would last 5000 miles with out dropping either a piston or cylinder skirt?I bet it would..same as the poo is..so yes..I agree the poo rod length is ok for the bore & stroke of the motor.. if you can tighten piston clearence to stop the skirt loading without scuffing pistons due to heat closing up clearences...then yes the stock rod ratio works..now to do it right with out changing rod length..i think you need both a new piston and thicker cylinder liner..thats to build a bullet proof motor...with that said...prove to me your piston/cylinder clearences solve the issues for good..and I will move your kit to the head of my list..but without a written guarentee against failure thats gonna be a hard sale from what I see...

 

[ruffryder]

Kelsey, pretty hard to compare the cfi motor with either of the other brands..just a totally differnt design.but with that said..yes the suzuki motor has same this, same that..but..it doesnt have an issue with cylinder loading..we both agree on that...why? easy..tighter piston clearence..and thicker cylinder sleeve....if you punch a cat out to the same wall thickness of the poo and build a piston at what polaris calls for specs are you sure it would last 5000 miles with out dropping either a piston or cylinder skirt?I bet it would..same as the poo is..so yes..I agree the poo rod length is ok for the bore & stroke of the motor.. if you can tighten piston clearence to stop the skirt loading without scuffing pistons due to heat closing up clearences...then yes the stock rod ratio works..now to do it right with out changing rod length..i think you need both a new piston and thicker cylinder liner..thats to build a bullet proof motor...with that said...prove to me your piston/cylinder clearences solve the issues for good..and I will move your kit to the head of my list..but without a written guarentee against failure thats gonna be a hard sale from what I see...

Sorry man, but this is pretty hard to read.. paragraphs would help..

 

[AKSNOWRIDER]

sorry ruffy..will do better...

 

[knifedge]

it wasn't unfortunate that i was the one that posted the cylinders and pistons were wasted, they were, they are. now, i, in no way have the motor building experience that you or many others do on this forum but i do know when i see and feel cylinders that need replated and pistons that need replaced.

i will definitely agree with you on the difficulty of accurately presenting tone and intention on the internet vs. over the phone, or even better yet, in person.

pv

--Can I have those "wasted cylinders" --Please?

 

[RKT]

Kelsey, pretty hard to compare the cfi motor with either of the other brands..just a totally differnt design.but with that said..yes the suzuki motor has same this, same that..but..it doesnt have an issue with cylinder loading..we both agree on that...why? easy..tighter piston clearence..and thicker cylinder sleeve....if you punch a cat out to the same wall thickness of the poo and build a piston at what polaris calls for specs are you sure it would last 5000 miles with out dropping either a piston or cylinder skirt?I bet it would..same as the poo is..so yes..I agree the poo rod length is ok for the bore & stroke of the motor.. if you can tighten piston clearence to stop the skirt loading without scuffing pistons due to heat closing up clearences...then yes the stock rod ratio works..now to do it right with out changing rod length..i think you need both a new piston and thicker cylinder liner..thats to build a bullet proof motor...with that said...prove to me your piston/cylinder clearences solve the issues for good..and I will move your kit to the head of my list..but without a written guarentee against failure thats gonna be a hard sale from what I see...

AK, thanks for the response.. So, the rod ratio is fine (we agree) there are piston and cylinder design issues and only 1 is easily and affordably adressed. I am glad we can agree on this..

As for the "hard sale" contrary to popular belief, I am not trying to sell you anything... Not sure where that came from?? Just in here discussing things...Not being snide.. just saying..

My shop has been around longer than most and has proven to supply reliable products that actually do what they are suppose to.. I pride myself on delivering proven set ups that work (like the drop in kit and patened head, for example )

We always test EVERY product for a year before release to the public.. I feel this to be a mandatory procedure (wish other shops would do the same). Only after the products have been thoroughly tested by us (and usually other testers) do we offer them to the public..

We figure if we can not destroy it in 1 full season of trying (usually 3000 mountain miles) then others will have the same success.

This method and has treated us well over the decades and hopefully will continue to do so... It would be nice to have the luxury of 3 years of solid testing but we all know that would be counter productive.

Others made a killin' developing Dragon products, we chose to pull out because the issues were not fixable in our opinion.. We have sold a few drop in kits to Dragon owners ONLY AFTER I gave them the "spill" that the engine's issues are still not fully addressed..

We purposely pulled out of the Dragon market because we felt that there were just too many issues assciated with that engine. so we made a business decision to not offer anything for that. This should speak volumes as to how the ethics are within RK Tek.. (If we can not really fix it, we will not put out a product for it claiming a fix)

I do appreciate your inputs and civility..

Good luck with whatever mods you do..

Kelsey

 

[knifedge]

--OEM engines and the 858 do not have cylinder sleeves. When the cylinders are
bored out and plated, the cylinder skirts get even thinner than stock. Cylinder skirt
thickness is apparently not the issue.

--As RKT stated, not a single skirt has broken on any of his kits with hard use and many miles testing

 

[AKSNOWRIDER]

--OEM engines and the 858 do not have cylinder sleeves. When the cylinders are
bored out and plated, the cylinder skirts get even thinner than stock. Cylinder skirt
thickness is apparently not the issue.

--As RKT stated, not a single skirt has broken on any of his kits with hard use and many miles testing

yeah I know how the cylinders are made, evidently polaris thinks there is an issue since the word is the 13's will have thicker skirts in the cylinders....and for kelseys kits not breaking any..how many kits and how many miles on each kit? I doubt any have gone over 1500 miles and most pro's stock are living to 2000+ already..I would think 2500+ miles would be the least to even start to think about saying they are totally reliable...but thats my opinion....
Let me ask..if you spend 3-4-5-6 grand on a kit to improve performance and reliability , what would be acceptable life before it needs overhauled? Since a broken skirt(either piston or cylinder) pretty much wipes out a cfi motor it could get very spendy very fast..I would expect a "kit" that is advertised to fix the issues and add performance to go at least 5000 miles reliable..with only a ring change for performance reasons at about 2500 miles..

 

[AKSNOWRIDER]

AK, thanks for the response.. So, the rod ratio is fine (we agree) there are piston and cylinder design issues and only 1 is easily and affordably adressed. I am glad we can agree on this..

As for the "hard sale" contrary to popular belief, I am not trying to sell you anything... Not sure where that came from?? Just in here discussing things...Not being snide.. just saying..

My shop has been around longer than most and has proven to supply reliable products that actually do what they are suppose to.. I pride myself on delivering proven set ups that work (like the drop in kit and patened head, for example )

We always test EVERY product for a year before release to the public.. I feel this to be a mandatory procedure (wish other shops would do the same). Only after the products have been thoroughly tested by us (and usually other testers) do we offer them to the public..

We figure if we can not destroy it in 1 full season of trying (usually 3000 mountain miles) then others will have the same success.

This method and has treated us well over the decades and hopefully will continue to do so... It would be nice to have the luxury of 3 years of solid testing but we all know that would be counter productive.

Others made a killin' developing Dragon products, we chose to pull out because the issues were not fixable in our opinion.. We have sold a few drop in kits to Dragon owners ONLY AFTER I gave them the "spill" that the engine's issues are still not fully addressed..

We purposely pulled out of the Dragon market because we felt that there were just too many issues assciated with that engine. so we made a business decision to not offer anything for that. This should speak volumes as to how the ethics are within RK Tek.. (If we can not really fix it, we will not put out a product for it claiming a fix)

I do appreciate your inputs and civility..

Good luck with whatever mods you do..

Kelsey

Kelsey, honest question here..how can you do kits for a pro CFI-2 motor but not for a dragon CFI-4 motor...every part is the same in the long block except for the cylinders which due to polaris changing injector manufacturers resulted in a differnt boss for the injectors to mount to.So if the mechanical issues of the dragon motor made it unfixable to RKT, then it should be the same with the PRO...
As for the rod ratio being fine..yes and no..if you change the piston and cylinder(better material in the piston and thicker material in the cylinders)yes, I think it can be an extremely reliable motor. without doing that, I think its just a matter of time before it takes a skirt off, maybe that limit will climb a 1000 miles beyond what it is stock, but i think it will eventually as long as a thinner cylinder is used..now if you change to a different, thicker cylinder with the new piston, yes I think this rod length will work.

 

[RKT]

Kelsey, honest question here..how can you do kits for a pro CFI-2 motor but not for a dragon CFI-4 motor...every part is the same in the long block except for the cylinders which due to polaris changing injector manufacturers resulted in a differnt boss for the injectors to mount to.So if the mechanical issues of the dragon motor made it unfixable to RKT, then it should be the same with the PRO...
As for the rod ratio being fine..yes and no..if you change the piston and cylinder(better material in the piston and thicker material in the cylinders)yes, I think it can be an extremely reliable motor. without doing that, I think its just a matter of time before it takes a skirt off, maybe that limit will climb a 1000 miles beyond what it is stock, but i think it will eventually as long as a thinner cylinder is used..now if you change to a different, thicker cylinder with the new piston, yes I think this rod length will work.

AK

No problem.. glad to answer.. But I will ask one thing of you.. Please to not add to the "hear say" and speculation by "guessing" at how many kits are out there running and how many miles are on them... I am asking this in the most polite manner possible via typing...

WHY add conjecture and guess to posts?? (this is the problem with public forums... there is no facts to support the typing)
I just do not understand this.. If you have hard facts regarding the number of drop in kit and miles on them, .... then post them.. but to mention about products that you have no facts regarding the quantity or mileage is simply not fair to the readers nor to RK Tek.. Sound fair enough? Again, I am ASKING this in a very polite manner.

The facts are that there are several with over 1500 mile son them, one of them winning the Beaver Mounatin Hill climbs a month ago and still going strong today. having said all that, we have torn down some and have found some areas where we need to make improvements and are doing so for next seasons kits (same with the 858)

Also, as for the 2013 cylinders and cases being altered.. I sure hope you are right... But, again, total speculattion at this time . We will know soon enough.. again, I sure hope it is true!!


As to your question.. the Dragon cylinder is very different from the Pro cylinder. It is much more than just the injector bosses.

The skirts are very different, the porting is different, to name a few.. The 4 injector system causes problems that can not easily be addressed..
The pistons were also very different and while we saw a great opportunity to replace the , then single ring piston, with one ours, we simply could not morally get past the other issues present in that power-plant..

It may have been he wrong decision, but it is one I made and stand by..

Hope this answers your questions

 

[AKSNOWRIDER]

I agree on the guessing...and no I dont have any idea how many kits or the miles on them..my above statement was based on the fact that they havent been known to be out there but about a 1/2 season and you had said you figure 3000 miles was a season...with that said..how many actual on the snow kits do you have and actual miles on them(by that 30 % have well over 2000 miles, 30% have 1200 miles and so forth), if you dont mind sharing that is..if not I understand..
I want you to understand kelsey, I could(and most likely will) be grilling the other builders as well before I make up my mind on what I am going to do..its not personal, I as you hinted at earlier in a post..do have engine building experience..and I have built full no holds barred race engines, so yes, I do have a good idea what I think it takes to make one of these run..I am not saying your way wont work, not at all(not enough info to make that judgement yet), I am just trying to ask the questions and get honest answers that will not only help me decide, but allow others that dont know anything about motors learn and understand what the issues and fixes are for this motor, and which kit is the right answer for each persons needs.

 

[RKT]

I agree on the guessing...and no I dont have any idea how many kits or the miles on them..my above statement was based on the fact that they havent been known to be out there but about a 1/2 season and you had said you figure 3000 miles was a season...with that said..how many actual on the snow kits do you have and actual miles on them(by that 30 % have well over 2000 miles, 30% have 1200 miles and so forth), if you dont mind sharing that is..if not I understand..
I want you to understand kelsey, I could(and most likely will) be grilling the other builders as well before I make up my mind on what I am going to do..its not personal, I as you hinted at earlier in a post..do have engine building experience..and I have built full no holds barred race engines, so yes, I do have a good idea what I think it takes to make one of these run..I am not saying your way wont work, not at all(not enough info to make that judgement yet), I am just trying to ask the questions and get honest answers that will not only help me decide, but allow others that dont know anything about motors learn and understand what the issues and fixes are for this motor, and which kit is the right answer for each persons needs.

Ak, ther ei sno way for me to know how many miles every customer puts on any of my kits.. These kits are shipped world-wide. Again.. that information is not known to me.

I can only speak to what I have personally witnessed..

Like I said, I found some areas in the piston kit and Big Bore that warrant a change.
I usually make changes every season on MOST of my products.. Like everything else, the more you look at and the more testing you complete, the better you can improve your products..

This is true with ALL my products and I suspect 2014 Pro kits will differ from the 2013 kits.. Again.. this is the way I develop products and keep making them better..
Staying with the status quo is simply not an option for me... never has been.

Case in point, 2012 was the 1st season that I did not alter the Doo 860 kit and we did the very first EVER 860R kit in Nov 2006--> so, 5 full years of testing and improving until I was satisfied with not changing it anymore. I am sure the Polaris and Cat kits will suffer the same fate.. LOL

When you design your own custom products from scratch and personally develop and test them, you get a very good understanding on how the product is really doing and how improvements can be made.

We design ALL of our pistons 100% from scratch (blank sheet of paper) and have a custom process for having them manufactured. Our combustion chamber design has been issued a patent.. that is how unique it really is... so, we REALLY do approach and develop products on our own ground and , hopefully, we get it right...


Our Test 858 sled (this year) new owner has already been informed that we want to make some changes for next season. We really did not want to even sell the sled....but we were convinced otherwise..