Rk Tek 858 Kit

[Octane]

I have a 11 Pro with a little over 2000km and i can tell shes tired.
So the solution in my mind is either the drop in kit ( 800$) or the 858 kit (2100$)
Does anyone here have experience with either? I'll also be adding an slp pipe/can and pcv combo to which ever set up i end up going with?

Just looking for some input before i tear it down!

Thanks
Octane

 

[cdnemsguy]

Well not in a Poo, but I just put the drop in kit (13.5:1) in my 800R XP. It has Boyesen reeds, DJ clutch kits and can. This was all done prior so after I put the drop in kit in her, I am very impressed and can feel the difference. Seems the extra power makes the other add ons work better. Sounds snappy, pulls great and no jetting or timing required. I shy away from the 860 BB kit not only because of the extra $, but i want to drive her without constantly checking its not burning up, leaning out, temp too hot etc. I am very happy with the kit for my XP anyways. I can now just ride and feel confident that the XP wont leave me stranded.

 

[Rhodesie]

I installed Kelsey's drop in kit (13.5:1) in my 12 and have put 94 miles on it so far. The first 50 miles on the first day i rode i was just playin and breaking it in. The second day i rode it like i normally would. Way less vibration, and pulls 8350 rpm and it holds it. 7000', 2.5 ce track with 64g weights. This thing pulls like a train. No fuel controller, 91 octane, stock exhaust. I never saw the det light once and never gave me a any indication that it was not happy. It just flat worked and worked well. Stock cylinder pressure was 118 psi, after warm up and cool down with drop in kit cyl pressure was 134psi, cold after 94 miles was 138 psi. Next year when i but a new one with the Fuji crank is when i am going with Rk's big bore. I have installed a couple sets of direct replacement pistons for friends and they have way less vibration and more pep also. Just installed another drop in kit for a bud today in his 12. There is just way less shake without the stock pistons. Call him and talk to him. You won't be disappointed.

 

[96sherm]

I'm curious as to why you think its "tired" with 2000kms on it? I have 3400 on my '11 Assault RMK and swapping with my buddy's '12 RMK Assault with around 1000kms, it doesn't feel any different. For some reason, his will rev to 8200 if he holds it, mine stops at 7800...

FWIW, I'd stick with the stock displacement, like other have already said, reliability is the key.

 

[+SLEDWRECKS+]

Same here, have 3400 km on my 11 and installed a PAR 13.1 head this fall, and cylinders & pistons looked real good (even with the spray). Going to get this RK piston kit and put it on the shelf cause it will be needed.
If your only pulling 7800 - have you checked your primary - could be wornout bushings and/or weights (if you haven't already looked of course)

 

[96sherm]

It crossed my mind to check the clutching. I know my belt is set riding pretty high. With the mountain weights (factory) I can pull 8050-8100 on the flatland, but with the flatland weights (factory 68?g) it was only 7750-7800. I'll have to look at the bushings.

 

[Chrisco]

PMS also makes a piston kit for the pro as well $650.00 we keep them in stock. It will also do the same as the rkt kit.

 

[Rhodesie]

PMS also makes a piston kit for the pro as well $650.00 we keep them in stock. It will also do the same as the rkt kit.

The pms kits i installed were replacement pistons and spacer and that would be comparable to Kelsey's direct replacement kit. The rkt big bore and drop in kits come with the head and choice of cr domes also.

 

[Dazzler]

PMS also makes a piston kit for the pro as well $650.00 we keep them in stock. It will also do the same as the rkt kit.

Chris, is the PMS kit forged or cast pistons? also is this the kit with taller pistons, spacer under the cylinders and I would use my existing head on the 2011?

 

[Chrisco]

Chris, is the PMS kit forged or cast pistons? also is this the kit with taller pistons, spacer under the cylinders and I would use my existing head on the 2011?

Yes it is, and yes forged.

 

[RK Tek]

PMS also makes a piston kit for the pro as well $650.00 we keep them in stock. It will also do the same as the rkt kit.

With all due respect, the PMS kit and the 858 kit are very different.. same comparing the PMS kit with our Drop In kit.. they could not be more different..

The 858 kit is an OVER-BORE.. Meaning, the cylinders have been bored, ported, and replated..It also comes with our Patented combustion Chamber design in either the Cheater ot Billet version.. The PMS kit has NONE of the beforementioned components.. VERY different in design and performance (especially)

The Drop In Kit is something that RK Tek pioneered with the Ski Doo Engines back in 2001 ( 12 years ago) We carried this technology over to the Polaris and the Cat as well.. It is a proven kit being used by many of the top riders (Including VOHK and his Possee) that really does deliver the performance and addresses an internal piston issue as well.. This kit works exceptional on the turbo as well as, the N/A engines..

Again, not even remotely similar to ANY other kit on the market, especially, the PMS kit..

Hope this clears up a few misconceptions...

 

[Tyson.H]

With all due respect, the PMS kit and the 858 kit are very different.. same comparing the PMS kit with our Drop In kit.. they could not be more different..

The 858 kit is an OVER-BORE.. Meaning, the cylinders have been bored, ported, and replated..It also comes with our Patented combustion Chamber design in either the Cheater ot Billet version.. The PMS kit has NONE of the beforementioned components.. VERY different in design and performance (especially)

The Drop In Kit is something that RK Tek pioneered with the Ski Doo Engines back in 2001 ( 12 years ago) We carried this technology over to the Polaris and the Cat as well.. It is a proven kit being used by many of the top riders (Including VOHK and his Possee) that really does deliver the performance and addresses an internal piston issue as well.. This kit works exceptional on the turbo as well as, the N/A engines..

Again, not even remotely similar to ANY other kit on the market, especially, the PMS kit..

Hope this clears up a few misconceptions...

With all due respect he said piston kit not big bore. I am sure he wasn't comparing the PMS kit with your big bore 858 COME ON. Could you tell me about some technology that you are getting with your drop in kit compared to the others on the market. Must be something pretty sweet for the extra 150 bucks. Tell use about it cause you didn't say much about you drop in kit. Just said its better, that about it, but why and how EXPLAIN THE TECHNOLOGY cause to me the PMS kit and yours are similar and PMS is 150 cheaper.

Please clear up some of theses misconceptions...

Thanks

 

[Chrisco]

Thanks for the tip Kelsey I was talking about the drop in kit but ok. So your drop in kit is above all other drop in kits specialy the PMS kit... Why???? Let me guess your BB is superior to the P\A 910cc also.

 

[Rhodesie]

With all due respect he said piston kit not big bore. I am sure he wasn't comparing the PMS kit with your big bore 858 COME ON. Could you tell me about some technology that you are getting with your drop in kit compared to the others on the market. Must be something pretty sweet for the extra 150 bucks. Tell use about it cause you didn't say much about you drop in kit. Just said its better, that about it, but why and how EXPLAIN THE TECHNOLOGY cause to me the PMS kit and yours are similar and PMS is 150 cheaper.

Please clear up some of theses misconceptions...

Thanks

the pms kit does not come with a head and domes for $650.00. rk's DROP IN KIT does for $800.00. rk's DIRECT REPLACEMENT piston kit does not come with the head and is $375.00. why does the cylinder shim and bolts in the pms kit cost an extra $275.00?

 

[Chrisco]

Tell ya what why dont you put your 858 kit with the pretty blue head in a box for a 2012 and call me in the am for payment 780-963-0080 and ill let you know and everyone else on this forum how it works Igot a block on the bench right now to put it in and we are going to NPP on the 28 to put the 910 on the dyno so why not bring the 858 just makes sence. So If you got stock call me

 

[Chrisco]

The PMS kit is 585 us I guess the bolts spacer and base gasket and dowl pins is the extra cost.

 

[High Velocity]

Game on !! I'll be watching this thread closely now. I've seen a 910 run that was running way, way fat and even so, the 858 has really big shoes to fill. Granted, the 858 is significantly less money. It would be very interesting to see both engines on the same dyno, same day.


Done fishing. Let's go sledding !!

 

[Briand]

I have installed the dropin kit for my 12 800 pro and could not be happier. This kit really preforms well. I have the 13.1 domes for my elevation (2500 ft). and have not rode it yet in the mountains , just at home here. Basically Kelseys drop in kit has lighter and shorter pistons which changes the port timing allowing better airflow and better stock pipe performance. Motor runs way smoother much quicker acceleration and harder midrange and topend pull. For me it has been the best aftermarket addon I have purchased.
Whats really amazing here is that my motor stock ran best at 8150. I added 3 grams of weight to the primary and the motor runs at 8350 rpm. so not only did I add more weight but also gained 200 rpm, very impressive results.

 

[ditch1000]

I have installed the dropin kit for my 12 800 pro and could not be happier. This kit really preforms well. I have the 13.1 domes for my elevation (2500 ft). and have not rode it yet in the mountains , just at home here. Basically Kelseys drop in kit has lighter and shorter pistons which changes the port timing allowing better airflow and better stock pipe performance. Motor runs way smoother much quicker acceleration and harder midrange and topend pull. For me it has been the best aftermarket addon I have purchased.
Whats really amazing here is that my motor stock ran best at 8150. I added 3 grams of weight to the primary and the motor runs at 8350 rpm. so not only did I add more weight but also gained 200 rpm, very impressive results.

What did you install for weights??? I have the exact same setup coming for a 12. I'm thinking of installing Dalton adjustables.

 

[Briand]

What did you install for weights??? I have the exact same setup coming for a 12. I'm thinking of installing Dalton adjustables.

I have the 68 gram MTX weights. Honestly I don't know what I going to run in the mountains. I'm thinking I will try the 10-66, 10-64 at 7000 ft and get the clutching (Secondary) setup to run with the stock weights then fine tune with the MTX. Just don't know yet what will work up high.