Two Stroke Head

Thought I would share our experience with the RK-Tek head. 

We've used other aftermarket heads in the past. Used S3 on both our trials bikes and RR's. Never been that impressed with them  on ether style of bikes and had a few issue. 

Also used the high compression heads from Beta USA. These are milled down stock heads. They do give the bikes a little boost and is what we had been running just to get a little more out of the bikes. 

So now we've had the RK-TEK head on the bike for a few weeks and are really impressed! First thing I like is the heads are tailored to you. Type of riding, elevation and gas type used. We actually got two. One for Ty's practice bike that gets used for everything from MX, GP, trail riding, Extreme riding to being ridden like a trials bike. Since this bike gets ridden so much we set it up for pump gas. The other head will go on his dedicated Endurocross race bike and will be run on race gas.

So far only the practice bike head has been installed. Race bike hasn't been built yet. Ty is super happy with the power it has helped get out of his 2018 300. He likes a strong smooth power band because he feels like he can push that much harder and keep the bike hooked up. Sometimes it's hard to balance that with making a two stroke fast. The RK-TEK head helps in both those areas and if anything he feels the bike revs out a little further and cleaner. 

Can't wait to try the other head on the race bike. Should really help with the log jumps etc. that are right out of corners. That's been the biggest concern going back to a two stroke for EX. imageproxy.php?img=&key=b3312acf975e3c54

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Edited by ccullins

Very interesting design that on the RK. Would it be possible to order one head with 2 domes?

Also Chris what was your concerns with the S3 head? I am running one now on my 2017 and it certainly helped with pipe bang and jetting (before catastrophe arrived anyway...). RK-Tek looks a more advanced design and may work better but I haven't found any particular flaw on the S3.

The magic and patent I believe is in the knurled surface texture.  It would be interesting to duplicate that on your current head, with no other changes other than to correct volume for material removed, and see what happens.

5 hours ago, dirtbird said:

Very interesting design that on the RK. Would it be possible to order one head with 2 domes?

Also Chris what was your concerns with the S3 head? I am running one now on my 2017 and it certainly helped with pipe bang and jetting (before catastrophe arrived anyway...). RK-Tek looks a more advanced design and may work better but I haven't found any particular flaw on the S3.

Should have clarified, the issues with the S3 heads was when using them on Sherco trials bikes. That was back when they first started producing them. Didn't have any reliability issues when trying it on the RR, just didn't find much of a benefit so figured why bother. Got more out of head from Beta USA. 

I gotta ask what is pipe bang? I hadn't heard that term before. 

59 minutes ago, GP said:

The magic and patent I believe is in the knurled surface texture.  It would be interesting to duplicate that on your current head, with no other changes other than to correct volume for material removed, and see what happens.

You can send in your existing head and they will do it. I think it's $150.

My 250RR head is already done by RBD for pump gas at sea level and works quite well.  Funny, when I got the head to do my 250 conversion the compression was really high, too high for pump gas, so maybe it was one of the high comp Beta heads.   $150 is better than $325 if like me you don't need multiple domes for elevation changes, and the Beta head has plenty of cooling as well.  Maybe next time.

Thank you for the review! I've thought about sending them my stock head to work their magic. This may have pushed me over the edge.

On 3/13/2018 at 7:03 AM, GP said:

The magic and patent I believe is in the knurled surface texture.  It would be interesting to duplicate that on your current head, with no other changes other than to correct volume for material removed, and see what happens.

Appears to be a variation of the Singh groove principle.

Edited by widebear
6 minutes ago, widebear said:

Appears to be a variation of the Singh groove theory.

Not a variation of Singh at all. Totally different concept.  Singh has a patent.. if it were remotely close, the RK Tek Patent would not have been issued

 

3 hours ago, HERA said:

Not a variation of Singh at all. Totally different concept.  Singh has a patent.. if it were remotely close, the RK Tek Patent would not have been issued

 

 :Totally different concept:.Would you please elaborate on that point since you seem to be in the know?

 

I just dug this up as a reference to my original statement.They appear somewhat different but the concept appears to be similar in some respects.

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQQDs9Vc7SO5Otgzq04wOovf0mRN_Bvk9gmYD5kGKt3HCA-54np

Edited by widebear
On 3/12/2018 at 0:22 PM, ccullins said:

Thought I would share our experience with the RK-Tek head. 

We've used other aftermarket heads in the past. Used S3 on both our trials bikes and RR's. Never been that impressed with them  on ether style of bikes and had a few issue. 

Also used the high compression heads from Beta USA. These are milled down stock heads. They do give the bikes a little boost and is what we had been running just to get a little more out of the bikes. 

So now we've had the RK-TEK head on the bike for a few weeks and are really impressed! First thing I like is the heads are tailored to you. Type of riding, elevation and gas type used. We actually got two. One for Ty's practice bike that gets used for everything from MX, GP, trail riding, Extreme riding to being ridden like a trials bike. Since this bike gets ridden so much we set it up for pump gas. The other head will go on his dedicated Endurocross race bike and will be run on race gas.

So far only the practice bike head has been installed. Race bike hasn't been built yet. Ty is super happy with the power it has helped get out of his 2018 300. He likes a strong smooth power band because he feels like he can push that much harder and keep the bike hooked up. Sometimes it's hard to balance that with making a two stroke fast. The RK-TEK head helps in both those areas and if anything he feels the bike revs out a little further and cleaner. 

Can't wait to try the other head on the race bike. Should really help with the log jumps etc. that are right out of corners. That's been the biggest concern going back to a two stroke for EX. imageproxy.php?img=&key=b3312acf975e3c54

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Im interested in your practice bike pump gas experience. Thanks for sharing. I appreciate honest real world posts that you have a long nice history of sharing. I look forward to the race gas report!!!!

Funny I went from sort of interested and just wanted to learn about this head :ride:for a far future possible purchase to now which head should I get and what color.

Edited by hawaiidirtrider

If you send you're stock head to RK, do they do that faceted cut to the bowl or just trim it to raise the compression?

Aw man. I totally would have went with blue (over black) had I known it was an option. 

3 hours ago, randysoo said:

If you send you're stock head to RK, do they do that faceted cut to the bowl or just trim it to raise the compression?

I don't know for certain, but I believe they put all of those groves in it.

21 hours ago, hawaiidirtrider said:

 

Im interested in your practice bike pump gas experience. Thanks for sharing. I appreciate honest real world posts that you have a long nice history of sharing. I look forward to the race gas report!!!!

Funny I went from sort of interested and just wanted to learn about this head :ride:for a far future possible purchase to now which head should I get and what color.

Next week should Know how the other head does. Race bike in the build process!

 

I'm no motor expert or claim to know what makes one thing work over another. However the reason these work is more than just the grooves. Don't know if it really shows in the pictures, but the whole combustion chamber is a completely different shape. 

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On 3/12/2018 at 0:22 PM, ccullins said:

Thought I would share our experience with the RK-Tek head. 

We've used other aftermarket heads in the past. Used S3 on both our trials bikes and RR's. Never been that impressed with them  on ether style of bikes and had a few issue. 

Also used the high compression heads from Beta USA. These are milled down stock heads. They do give the bikes a little boost and is what we had been running just to get a little more out of the bikes. 

So now we've had the RK-TEK head on the bike for a few weeks and are really impressed! First thing I like is the heads are tailored to you. Type of riding, elevation and gas type used. We actually got two. One for Ty's practice bike that gets used for everything from MX, GP, trail riding, Extreme riding to being ridden like a trials bike. Since this bike gets ridden so much we set it up for pump gas. The other head will go on his dedicated Endurocross race bike and will be run on race gas.

So far only the practice bike head has been installed. Race bike hasn't been built yet. Ty is super happy with the power it has helped get out of his 2018 300. He likes a strong smooth power band because he feels like he can push that much harder and keep the bike hooked up. Sometimes it's hard to balance that with making a two stroke fast. The RK-TEK head helps in both those areas and if anything he feels the bike revs out a little further and cleaner. 

Can't wait to try the other head on the race bike. Should really help with the log jumps etc. that are right out of corners. That's been the biggest concern going back to a two stroke for EX. imageproxy.php?img=&key=b3312acf975e3c54

IMG_3220.JPG

IMG_3221.JPG

IMG_3223.JPG

IMG_3224.JPG

IMG_3191.JPG

IMG_3222.JPG

Funny I would think that the log jumps coming out of the corners would be better with the 2 stroke..So the 4 stroke seems better in those situations? No matter your description makes the bike work better throughout and even on top.  Smooth planted feel sounds like exactly what I want. Your practice pump gas dome is set up for sea level??? How you describe what the practice bike is used for sounds exactly like what I like. Thanks again for the detailed explanations.

The 'modify the OEM head' route looks much more attractive to me since I won't have to deal with extra customs fees. 

Probably will do it in the close future.. 

42 minutes ago, dirtbird said:

The 'modify the OEM head' route looks much more attractive to me since I won't have to deal with extra customs fees. 

Probably will do it in the close future.. 

Ive been focusing on the whole complete head to possibly get. I figure the overall volume of coolant is better for one thing but I guess I should talk to the RK owner to learn from the source about what you get for your money from a cut head and the whole head. . I’ll be talking about what kind of dome for local terrain and riding anyway. So far it’s just been internet info. There’s been some that have the head and all have seemingly given rave reviews of the RK head. .. and of course all the bullshitters that don’t know anything but diss the head without trying. Im also wondering about the choice of color for the head too. Im going back and forth on metal color or black or maybe red? Idk. 

This shiz looks hot. 20180318_193918.jpg

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