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Why don't you contact Kelsey at RK tech and ask him. As for the Cudney, I run his head with stock jetting except for 20 pilot jets a .010 shim on the jet needles and a Holtzman Tempa Flow on 91 octane gas.
 

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Discussion Starter · #3 ·
Well I just picked up this head (RKT) for a good deal and I thought somone may know. I have many other things done to the sled so as far as jetting goes i think Im close with the Cudney. To ask RKT about jetting my sled would probably put me back to sqare one and I would work from there. Realy what I was looking for I guess is, does the RKT tend to run richer or leaner? I suppose the change in compression would make a difference but would just the head make a diff.
 

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Well I just picked up this head (RKT) for a good deal and I thought somone may know. I have many other things done to the sled so as far as jetting goes i think Im close with the Cudney. To ask RKT about jetting my sled would probably put me back to sqare one and I would work from there. Realy what I was looking for I guess is, does the RKT tend to run richer or leaner? I suppose the change in compression would make a difference but would just the head make a diff.[/b]
I guess a better question here would be "do I need to add fuel for more cooling" as all thing being equal jetting should stay the same unless engine displacement is increased. Keeping in mind that the same vacuum signal to the carb's venturi exists so F/A ratio is un altered. The cooling effects of a richer mixture offsets mild detonation but costs in Brake Specific Fuel Consumption IE pocket book. Unless you have added twin pipes or a reduced back pressure muffler which would directly affect flow through this pump, jetting remains the same. One thing I have read about some RKT products are that they are not friendly with after market mufflers.
 

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Discussion Starter · #5 ·
I have heard the same about the pipe not working as well on some RKT products and yes I have a BMP pipe. I think it has to do with the tight squish band they use but not sure. When I compare the two you can see this. Also the domes on the RKT are beveled or noched and the Cudney are smooth on the back side. Maby this is cooling the head more. When I look at the instructions for RKT is says it will probably need smaller mains. Cudneys says nothing about jetting. I guess I will have to try it and see. It would be nice to be able to throw on another head when I go to places I know I cant get 91-93 octane.
 

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If I were you, I'd carry a little octane boost for those times. I've spent a lot of money and made some enemies having octane checked after my Friends have had unexplainable burn downs in remote locations. When tanking at blend pumps, wait for someone to fill up on 91 or 94 before you take on fuel because there's 1/22 gallon of last choice in the hose, more so if there's an in-line spin on filter. Watch out for ethanol blends too. I've run Bill's head on 87 octane taking it easy on trips from the Abitibi Canyon without any drama.
 

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Discussion Starter · #7 ·
Sounds good, I have heard the same from others about Bills head. Maby Ill tune it in and leave it. What kind of octane booster do most use? I have used some cheep stuff in the past but I allways wondered if it was doing anything.
 

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I have had good results (no burn downs) using NOS Octane Booster but the lion's share are pretty much the same. They claim to bring octane up to 7 to 10 points and add Nitro Methane MMT (oxygenation additive) and some "mystery chemicals" which are refined paint thinners. Just be sure to pre mix the booster in a jerry can before topping up your tank with it and be sure to use the entire fuel charge because the stuff drops out of chemical suspension after a few warm cold spells. It's heavier than gasoline so it will occupy the bottom of your fuel reservoir after long periods of time.
 

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I have had good results (no burn downs) using NOS Octane Booster but the lion's share are pretty much the same. They claim to bring octane up to 7 to 10 points and add Nitro Methane MMT (oxygenation additive) and some "mystery chemicals" which are refined paint thinners. Just be sure to pre mix the booster in a jerry can before topping up your tank with it and be sure to use the entire fuel charge because the stuff drops out of chemical suspension after a few warm cold spells. It's heavier than gasoline so it will occupy the bottom of your fuel reservoir after long periods of time.[/b]
I have used the NOS race formula too. I also use some stuff by Lucas Oil. Cost about the same and they have the same claims as the NOS booster.

BTW, I run the RK Tek head on my 800 with no problems. It didnt like the aftermarket pipes but works ok with an aftermarket can. I now run my stock pipe and stock can. The sled rips!!!
 

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Discussion Starter · #11 ·
Seems like not to many people like the pipe but I dont know why. Dynotech had a 800 with the BMP pipe and it made 151hp with no losses, same sled made 139 stock. The same sled they put a head on and trail ported then it made 163hp. I hope this is true cause that is the same setup I have. I cant wait to try it! Besides how could I take this pipe off now , it looks so dam nice in there!
 

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