Has anyone tried the Group K Big Bore 850 kit on the SXR?

[Bri577]

Has anyone tried the Group K Big bore 850 kit??

How did it go??

 

[GabeH]

I'm running a GroupK sleeper on my SXR with 1 oversize, so it's not the 850 but it's probably close to 800. It has a lot more power than the stock engine set up I was running before. My wife's Sxi Pro is running the Sleeper 800 and that ski was faster than the stock SXR and used less gas. I think Harry Klemm's setups are great for midrange performance with stock reliability. Very happy with our GroupK setups and would highly recommend!

 

[Bri577]

Thanks Gabe,

I'm pretty sold on it. Time to give Harry a call.

Thanks again!

 

[SXRDJ]

I'm currently putting mine altogether. It was definitely more money than I originally intended to spend but wanted to do it right. I did the 80mm nozzle bore as well as the impeller. Haven't fired it up yet but I do like their customer service and they are fairly quick at getting back to me with questions.


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[user_error]

For a stock ski the complete 850 kit works well, especially in conjunction with groupk's port matching and head machining. That said, I would not recommend it for a modded ski with a pipe.

the 850 kit uses nearly all the sleeve material that the oem sleeves can handle. Thinner sleeves are more prone to cracking, however, with a stock ski the RPM's are low enough to keep the piston speed within the range of long temp reliability.
A limited ski or likewise modded ski has a much higher piston speed, high enough that it puts the very thin sleeves of the 850 kit in danger of cracking.

Personally, i run both of my limited sxr's at 84.5mm bore, which is right around 830cc, and have not had a sleeve failure ever, even after HARD running for the last 4 years. I also bored my stock ski to 84.5mm bore and there is definitely a noticeable increase in low end "grunt".

 

[Baja 252]

Our SXR has over 200 hrs on our Group K 850 Kit. Just like the web page says, very linear powerband and lots more power than a stocker.

 

[user_error]

That is awesome, they (groupk) do great work. Did you get the whole shebang with ported intake and head milling, ect?

 

[Scorn800]

The group k kits give more power than stock and have great reliabilty. I have friends with Harrys kits on sxrs. I will say a stock sxr with a dry pipe will piss all over them. It's all what you want.

 

[Baja 252]

That is awesome, they (groupk) do great work. Did you get the whole shebang with ported intake and head milling, ect?

Yes, we have the complete kit with all options including the water exhaust mod. Our goal was stock reliability, smooth powerband and tons of low end power to help launch the heavy SXR off cruiser waves. It has worked out great for us, met our goals 100% and still very rideable for beginner riders. I also agree with what was said above, a modded SXR with a pipe will be faster.

Be sure to check the top pipe exhaust bolts and bracket on the front of the cylinder often, they have a tendency to vibrate loose and if they do the vibration will crack the top pipe. The good news is that pipe isn't ported so a replacement from eBay is easy to get. Also know the stock SXR used more fuel than our modded SJ, now with the kit it uses even more fuel. On a long ride the SXR will be 100% empty and the SJ's still have some fuel left before they switch to reserve.

 

[SXRDJ]

Damn. Well what did you guys run for a break in procedure?? 32:1 mixture and vary rpms?


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[Baja 252]

Yes, I followed his instruction sheet to the letter. Is he doing your carbs?

 

[SXRDJ]

Yup carbs have been bored also. This warm weather has me itching to finish up the project!


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[mybad]

I had a Group K big bore SXR. Brand new ski....unbolted engine....sent it to Group K. Setup exactly like Group K recommended. I didnt care for it. Sounded like a grenade. Vibrated like a mother. Had major concerns that were never resolved. I sold it 3 months later. So no long term durability data. Its the nature of the beast. I wouldnt build another one. Dont get me wrong I love Group K. Had them build me Hammer SJ 701 since. Which will crush that SXR 850

 

[SXRDJ]

Ok. I am beyond lost with this new bilge and cooling system.
Where does the barb fitting at the bottom of the exhaust manifold go?? I know they added one here

. Is it now dual cooling? Stumped lol


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[Baja 252]

Did you add a new 2nd line to the pump? (dual cooling)

 

[Baja 252]

Did Group K add a second fitting to the bottom of your manifold?

 

[Baja 252]

I'm guessing no to both.

 

[SXRDJ]

Correct assumption. There were legit no instructions for any of that.. There was a barb fitting in a plastic bag group k left that said fitting for pump..

The problem is that the ski came with a factory pipe. I removed all of that and the stock setup seems to be much different.

What's confusing me the most is this new fitting they added and I have no idea how to route everything to accommodate the new fitting or where to even add this fitting for the pump.. Meh.


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[Baja 252]

Did they do the water mod to your pipe? Did you get a small bag of water lines, filter and tees?

 

[SXRDJ]

Yea I did


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