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RKTek 858 is LEGIT!

how robust is the 858 kit, i ride average 5500k to 8000k. some of it can hit low 5000k high 8500-8700. will it make big difference if its set for elevations 5500 to 8000k

any help is much appreciated
 
Are you guys having to adjust the bd boxes much or have they been consistent? I want to get these things tuned once then ride to July if I please and really don't like pressing buttons after the initial tune. Also does the new bd box adjust for elevation changes? And are you guys not hitting the rev limiter at 8500 or does the bd box lift it?
Thanks
 
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Awesome post Jeremy! I've been waiting on mine from Vohk and will hopefully have it soon. Pretty excited to hear they are ripping this hard compared to the Carls price tag.
 
Are you guys having to adjust the bd boxes much or have they been consistent? I want to get these things tuned once then ride to July if I please and really don't like pressing buttons after the initial tune. Also does the new bd box adjust for elevation changes? And are you guys not hitting the rev limiter at 8500 or does the bd box lift it?
Thanks

just depends on how anal you want to be with it as far as the tune. the numbers that we have ran the past 2 rides 90% of people could run and never know or wonder what if i did this or changed that. they run great but there is almost always room for improvement. as far as altitude the bd box adds a percentage based fuel curve on top of the stock ecu's map, the stock map in the ecu compensates for elevation and the box adds the same curve in theory. however with major changes in elevation like 2000 feet to 10000 feet it seems like the numbers change a little. i believe the box eliminates the rev limiter, or lifts it. i've seen 8500 on my gauge and haven't hit the rev limiter yet
 
Are you guys having to adjust the bd boxes much or have they been consistent? I want to get these things tuned once then ride to July if I please and really don't like pressing buttons after the initial tune. Also does the new bd box adjust for elevation changes? And are you guys not hitting the rev limiter at 8500 or does the bd box lift it?
Thanks

TJ, I know you're not exactly in the back yard anymore after moving down south the other day, but Bparks has the same setup, and if you came up here I'm sure he'd let you ride it, and he's a dealer for Kelsey, so I'm sure he could get you a deal on a kit & help get it set up. Talking to him, he sounded like he hadn't had to mess with the box at all, and me not being a Pooboy he's got nothing to sell me on it.
 
Kaleb, I'd been talking with Bill about it quite a bit recently. Seems like he's pretty happy with it. If I'm up that way before I decide id definitely meet up with him. If you ride with him I'd be curious to see what you think of it too. I know its not a turbo but I think it would fit my riding style well.
 
nuggetau, Merlin, others: Check out the words of Erik Woog, aka VOHK, in this thread: http://www.snowest.com/forum/showthread.php?t=360405

NB! DISCLAIMER! Don't let me put words in Eriks mouth! This is what it is, nothing more.

Quote:
"I rarely chime in on threads like this, however feel there is a bit more to talk about here. First of all anyone who knows me knows I am a fan of power, period, it matter less who or how it comes as long as there is a ridiculous amount of it. That said, the Carl's build turned out great, the motor pulls with authority right off the bottom and got along well with the GTX 2860 at 11k'. It does however fall a tic short on the big end, which is consistent with what find on the natural aspirated units as well. Its a nice motor, and if it were a 1/3 the cost it would be a home run. The trouble starts and ends with the numbers, at more than double the cost of the RKTek 858 one would expect more, bottom line even the RKTek drop in will out leg the Carl's 900 and its less than $800. Generally budget is an important consideration to most riders considering any level of build, if one were to equate horsepower per dollar the choice is pretty clear... As Austin mention the RKTek 858 turbo with a GTX 2863 at a half pound less boost was MUCH faster than the 900 with only a minor sacrifice in bottom end punch due to the application of the larger turbo. For those wondering, the RKTek motor did not like the 2860 at all, it flows way too much air, we will be testing even larger turbos soon to explore the ceiling on this package. More on that later...Hope this helps to clear things up on this matter."

Yes, this is a turbo application, but you get some serious points in there. People have not complained out loud about Carls 900, on the contrary. It seems they have made a good kit and coupled it with good clutching.

Having researched pro 800 + big-bore myself, I am never the less left with a consensus on a motor that is just physically to small to begin with for big-bores to work (crankcase volume, transfer volume).

Proof is in the pudding and now more and more people tell us they liked Kelseys pudding. Seems he found a way for some cc's and aerodynamics to work together, making a package that works for the pro 800.

Well done Kelsey.



Anyone have a direct comparison with the PAR 910?
 
It will be interesting to see how they hold up after a 1000 miles, the skirts are THIN. How often does he recommend changing pistons? I saw and ran with one of the early 858s and although it pulled really well when new, it had some significant issues after a few rides. Hopefully those have been worked out.

PV
 
PV you must have the same opinion of the carls and par big bores in regard to the cyljnder skirts then as well right? I believe its been said they have thinner skirts than the RKT. And wasn't the kit you speak of a prototype?
 
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cylinder skirts on Carls and PAR Aftermaket cylinders are designed and made so they have thicker skirts than stock bored out.

There is no doubt the RK 858 is a great bang for the buck. The Carls motor has much more built into reliability imo.
 
cylinder skirts on Carls and PAR Aftermaket cylinders are designed and made so they have thicker skirts than stock bored out.

There is no doubt the RK 858 is a great bang for the buck. The Carls motor has much more built into reliability imo.

stock cylinder on left ,par 910 0n right, stock is thicker.

big bore1.JPG
 
PV you must have the same opinion of the carls and par big bores in regard to the cyljnder skirts then as well right? I believe its been said they have thinner skirts than the RKT. And wasn't the kit you speak of a prototype?

tdorval, settle. It was just an honest comment/thought. I will be interested to see how they hold up with how thin the skirts are considering there has been multiple skirt failures on the stock sleds. YES I KNOW RKT SAYS THAT ISN'T AN ISSUE WITH HIS MOTORS. And I hope it isn't. I hope they are as outstanding and reliable as people are claiming them to be. Yes the one I was around was a prototype, although I only remember that being stated after there were issues, but I very well could be wrong on that point. And no I don't have the same opinion of the other big bores as I haven't been around either of them nor was this thread discussing those. So what I'd really like to know now is,

Why are both the drop in and BB "Rev 2" kits now coming with a cylinder shim? Rod angle? Port timing? Case volume? Reliability? B/C all the cool kids are doing it? Other? None of the above?

PV
 
Why are both the drop in and BB "Rev 2" kits now coming with a cylinder shim? Rod angle? Port timing? Case volume? Reliability? B/C all the cool kids are doing it? Other? None of the above?

PV[/QUOTE]

Well if you look for example at mtntk i would say rktek uses it for reliability.. But if not, i find it kinda strange since he was so determined on not to use shim earlier like mtntk and bmp.
 
Please don't tell me to settle. I was only asking to make sure the facts were brought to the table. Bringing up a motor that had issues that was in fact a prototype and not mentioning that to me isn't right, which is why I brought it up. Also, I was actually asking the question about the other big bores, because I have read that they in fact have thinner walls than the 858 and would like someone to actually answer this with measurements not just stating such. I haven't run any of these so I have nothing vested, I would just like to hear some facts about this instead of people simply saying brand x is built more for reliability. Is asking people that say this to explain why they think this and back it up with facts, measurements, or what ever you have aside from simply saying shop x has a good track record too much?
 
I never said a word about the other big bores. And I simply stated my personal observation of a single kit that I never through a leg over. Why is it that this seems to offend you to such a degree?? And why is it you are so hyper sensitive to anything that might remotely be even the slightest perceived criticism of Kelsey's?? (which it wasn't BTW) And sense you brought it up, I think Carl's historic overall quality is pretty hard to argue with. Back to topic...

PV
 
While both carls and brads bb kits may have thin cylinder skirts, the cylinders are no longer stock. They have much larger cooling capacity and more uniform cooling which addresses much of the problem with this engine. The benifits of that far out weigh the thin skirts. I don't believe the skirts to be an issue with the cylinder itself addressed.
 
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