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Well now that our forest has reopened ive got several rides in on my 02 220 With fredette head and carb mods rev pipe. i seem to be now in a place in either or low or top end power. The bike had way more torque with the stock 33 carb which by the law of averages on the single track here we really need as I dont ride on top end on the roots as it loads the suspension too much. Ive been experimenting with the reeds and like I have read The boyesen fiberglass reeds are actually more responsive than to pro reeds you can see this when you look at them as the boyesen carbon fiber reeds are actually stiffer than the fiberglass reeds, there coming right back out. The bike runs great jetting at 42 pilot 1173 in the 2nd and 155 main just 1 clip makes a huge difference she will go great as long as you ride as aggressive as you can keeping momentum and clutching alot. I would like some of my lower mid range back that i lost with the carb bore.im even contemplating going back to a 33mm as I never really rode the bike at all with the stock carb. How does the fredette porting work is all around horse power? or only top end horse power? All in all I really dont need anymore top end horsepower im happy there for around here Im looking for a little more 250 type power. If anyone has a fredette ported 220 i would really like to hear what it is like! Have fun and ride safe!

I'm not a fan of Jeff's carb mod as it is more about making the 220 more like the 200 (ie; more top end power at the expense of low). Curious why you didn't go with an RB carb? Anyway, what pipe do you have on it, stock, desert, or woods?

Well i am a big fan of Jeff as he has all answers about the KDX and so far suspension. and head are working very good, I guess I dont have alot of experience with heavily modded carbs as this is the smallest CC bike Ive really ever liked and wanted to make it work, We are mostly single track here and the short wheel base is nice in the tight stuff and im impressed with it at high speeds not extremely twitchy or scetchy like you would think out of a 125 frame. I wonder if RB could finish what Jeff started Is there really that much difference? I looked for a power now but i guess there not available anymore. How much more torque can i expect with an RB modded carb is it better all the way around. I have the Gnarly Desert pipe on it and like it even though i never rode the bike in the woods with the stock carburator just riding it around the parking lot I remember it was quite torqey in the low end even with this pipe on it. I really did lose a considerable amount of torque but gained horsepower Are both possible out of this bike?

Ok, you and I have somewhat of the same setup on our 220's. My bike lugs like crazy. Check out some of my vids where I'm on the KDX. With the RB carb you don't lose torque but gain up top. The Power Now inserts couldn't even begin to compare to RB's divider setup. RB precision machines the carb for the divider and it precisely matches up with the slide. His divider keeps low throttle opening velocities higher which keeps the torque up even though he bores the carb out which increases top end. The best of both worlds so to speak. The other mods he does are proprietary so I don't know what all he does other than it just flat out works.

I'm going to second that about the RB modded carb. I don't believe I've lost any low end, feels like I actually gained a bit, but the top and middle are definitely improved. I would be surprised if he would work on a carb that's already been modified by anyone else. What he is selling today are new PWK carbs that have been modified. RB carb and head combo is probably the best engine mod I've done.

Thanks for the great info I called Jeff and I am going forward with porting, and probably will do the rb carb also If you are wondering why I am putting all this money in a KDX instead of buying a full blown 250 is im very short and I can at least touch a little with out cutting the seat or lowering the suspension Ive owned the ktm 200 but i like the KDX better in many ways, this is a very low hour bike so I will get years out of it
once i get it right. Thanks for the information on the Rb carb. Oh and something funny right out Of Jeff,s mouth is he never used race gas he said he always used pump gas! Can you believe at the highest level of racing he used pump gas? I found that hilarious! Ill post in a couple of weeks when I get it back together how different it is. What he claims is not just a little more power but considerably more all over that is what im looking for and maybe adding a tooth on the countershaft if it will pull it. The closer to a 250 the better. The price of porting is 180.00 not bad at all for the biggest performance boost there is for the KDX. Thanks again!

Make sure to report back on whether you like the porting or not. Good luck!

thanks I sure will Im sure it will take a few weeks with shipping and all, I did read one report online a guy posted he dyno'd his fredette ported 220 and he got 40 hospower on his, Jeff claims more power all over And it just is my luck that 40 horsepower is the exact number I like around here but it must have a broad powerband. I will post back in a few weeks

Any results on the JF porting job yet?

Yes I have been riding it a few times but it is awful hot here in Texas ill be riding more soon But so far it is awsome! Even the best riders on 450s cannot pull me in the fastest stuff we have here and they are always shaking off fore arm pump after a hard ride and i have none, It didnt hurt the stock low end power at all but gave it more mid range and will sing to the moon now on top end extending the power band a mile wide. It will suck the fuel down when on the pipe chasing the 450s i get 30 miles to the tank but thats not much worse than before the porting honestly.As with all of Jeffs mods they are always super high bang for the buck I highly recommend it its a total win win it still has all of its KDX manners when riding slow but now when you ask it to go you have to ride it like a 250, Its got to be in the 40 horse range on top now but is still very manageable and has great cornering speed.

You're getting me excited lol im currently waiting for him to send my cylinder back. Did you do any of thr RB mods as well, or just the porting?

Jeff did all my work Rb is just too expensive for me I can do the same things cheaper the good ol fashion way Ive never been blessed with enormous amounts of money you might check out my post " heres some help for poor low end performance" as a good boost to Jeffs carb boring
I now have a total of 150 in my carburetor and a total of 340 in my whole engine carburetor included Enormous bang for the buck, and i can no longer find any fault with it. The best way to explain the port work is its now a KX 220 with a heavy flywheel smooth as always but way more powerful. Dont be fooled by what seems to be little changes there as we are not paying by the pound of metal removed we are paying for exact science and that is what Jeff gives you. I hope you have had the head milled, bigger carb, pipe and silencer as all these are needed to get the full benifit from porting I make you a promise you will not be disapointed in any way It really is impressive and it will easily keep up with the 10 thousand bikes i know im doing it Smile

I gotcha. Well glad to hear the good feedback. Porting is definitely a science, not just hogging out metal with no regard for flow dynamics, i definitely get that. I'm eager to see where the material was removed.

Just can't wait to get mine back together and rip on her. Getting my RB modded head back today (man that was quick), already have a 34mm Lectron, rev pipe, silencer, and V3 reed cage on it... should pull pretty good, not sure if I can do much else to it now

As for the carb and head mods, RB Designs is superior to FRP.
RB Designs for carb and head. FRP for everything else.

I've always been curious about Eric Gorr vs FRP porting and how it changes the characteristics of the bike and power gain/loss.

I use Jeff on my KDX because he is the most successful rider that the KDX has ever seen at the highest level there is and he knows every millimetre of it. I asked Jeff if he could do my YZ but he said he sticks to what he knows best and i respect him for that he's not just after my money he is high quality KDX work. Eric Gorr just ported my YZ 250 not for more power just to take the hit out of it Eric has been around for decades and has ported over 50 thousand cylinders in his career, Both are top notch again it didnt look like he did too much but he did exactly what he said he would and the hit is gone.I only use tuners that test and or support AA pro-factory riders that way i get the benefit of the best work that money can buy and in both cases they were cheaper than any local guy that do not test with any AA pro's at all. My Kdx screams now it is impressive and it gets alot of comments "Thats a KDX" but the very Biggest wows come when I say the whole motor Carb, cylinder and head were 340 dollars they just cant believe that My YZ cylinder and head and return shipping and 1 power valve was 220 dollars I know alot of people are afraid of porting because they think it will only be a high rpm only screamer but in reality thats not true at all every bike i have ever ported has had a better and way wider powerband than stock. Not worse at all. Its those other guys that ruin your cylinders not the big names, Sure by trial and error they have messed up a few when trying to find perfection but you will never see those cylinders the big guys can afford to do that

Unfortunately Ron Black has retired ,, I feel dam fortunate to have had him do a few things for me