Tom L

Member
Dec 18, 2004
143
0
I just got my carb back from RB Designs. It's been too cold and snowy here for me to put it in and try it.

Can anybody tell me what to expect from this RB Carb mod on an '03 KDX220??? Alot more top end I hope. I have removed the airbox lid and put on an FMF Rev pipe and carbon fiber reeds. Just doing that helped the top end alot. Will the rb mod do much more??? I'll be sure to let you all know my feelings on it once it warms up a bit in PA!!!

Thanks for all your comments!!!
 

davidg

Member
Apr 30, 2002
193
0
You can expect more power, everywhere. I had the torque pipe, DF II reeds and air box mod on my 220. The carb a got from Ron was the best mod I did. Now I did get the modifed air styker carb from him. :laugh:
 

Tom L

Member
Dec 18, 2004
143
0
Thanks for the reply Davidg!!! Now I'm REALLY EXCITED!!! With the rev pipe I should have massive top end and lotsa that good 220 low end also!!! WOOHOO!!! :yeehaw:
 

Fred T

Mi. Trail Riders
LIFETIME SPONSOR
Mar 23, 2001
5,272
2
Not too much more off bottom really, but a much better midrange hit and pulls a bit more from there out if jetted correctly. (Ron ususlly sends it out pretty close) The 220 port timing restricts over rev so it will never really rev out with out Fredette porting done. You will notice the pull but don't expect a real big change. It helps though.
 

canyncarvr

~SPONSOR~
Oct 14, 1999
4,005
0
re: '..I should have massive top end..'

In a word...No.

That's with the understanding that the word 'massive' means something.

A repeat of what's already been said....just agreeing with Fred.
 

1tontj

Member
Mar 19, 2004
328
0
So, this mod isnot that big of a deal?
When I put the gnarly rev pipe on my 220 it made a huge difference. RB mod, not that big of a difference?

Was going to send my carb to RB, but this post makes me want to reconsider.

Thanks,
Phil
 

RTL

~SPONSOR~
Nov 13, 2001
328
0
I totally agree with the comments from Fred and CC. I think you may be missing the point they are making.

The RB mod on the 220 will deliver the benefits as stated on Ron's website. Massive topend, nope.

I would definately have the RB carb mod as one of my top mods as it does exactly what Ron states it will do! :)

Just my 02.
 

KDX200Kev

Member
Sep 22, 2003
161
0
The RB mod IMO is a must do. Even for my KDX 200 it made power all over the band. I would think it would be more significant for a KDX 220 because the OEM carb being only 33 mm. Check RB web page. As I recall he recommends head work for the KDX 220 to help it rev out.
 

JGrossijr

Member
Dec 29, 2004
36
0
I recently went for the RB dsigns carb mod. Already had the pipe, air box mod, & Boyesen reeds. The bike is much smoother and more responsive, particularly from part throttle. It actually is very smooth cruising fire roads at part throttle. A big improvement coming out of a corner from low rpm. A mild improvement in the over rev. Overall, a very good value after the other basics are covered.
 

idahotrails

Member
Oct 19, 2003
2
0
I have the RB Carb mod (on my 2003 KDX 220) and had RB do the head mod on the squish band at the same time. What I got was two things. First, immediate low rpm boost. My bike pulls harder at 1/8 throttle than my son's KDX (not modified) does at 1/4 throttle. (Of course my son says, "Why are you at 1/8 throttle, Dad? Get going--you're too slow." Second, smoothness is the word for what I got. My bike pulls smoothly from low rpm to high rpm. No sputters, no gaps in power, and really no hit. Just smooth strong pull. I did have a "woods" pipe at that time I first did this mod and was dissappointed that I got no new high rev power and no new top end speed. The carb mod/head mod didn't seem to effect high rpm at all. So I picked up a used Desert Rev pipe on **** and, whoaa, the desert pipe seemed to give it about 1500 more rpms at the top and about 8mph faster top speed than the woods pipe. It also added a bit of a hit, but not much. Overall the desert pipe, carb bored to 36mm, and head mod make the KDX into a different bike. Much stronger and yet more rideable. I ride high mountain switch backs so this makes me quite happy.
 

Zerotact

~SPONSOR~
Dec 10, 2002
1,001
0
Waiting to get my parts back from fredette, I sent my whole top end off, jug, head, carb, etc.... and when he was done he didn't have anything left to advise me on making more power. We'll see how she runs on my KDX220 with PC pipe.
 

canyncarvr

~SPONSOR~
Oct 14, 1999
4,005
0
Zero: You didn't ask...but some advice anyway? Pin FRP down on what gets done to your head. No, I don't know what he does for a 220, I DO know what he does for a 200...and it's basically nothing.

1ton: If you can read through much of any info on this board and come to the conclusion that an RB modified carb isn't that big a deal..well, I wonder how reaching such a conclusion, or even having such a question is possible! You are welcome to your opinion, of course. IF your conclusion is 'No big deal,' then your opinion is not only different from everyone (I think) else's, but..well, wrong!

Doesn't mean you're not welcome to it, though! ;)
 

Tom L

Member
Dec 18, 2004
143
0
Hey guys!!!! I put my rb-modded carb today and tried it out. It finally got up to 50F today, so I couldn't resist. I'm definitely glad I spent the $165. At first I was getting massive hesitation from idle to full throttle. It would almost stall out when I wacked the throttle from idle. But after getting it warmed up good and turning the air screw in to 1/2 turn out (Ron set it at 7/8 turn out), 99% of the hesitaion was gone. I figure once it warms up to 60Faround here, it'll be perfect. Throttle response is lightning fast now!!!! It definitely has more power everywhere, with a stronger upper-mid hit!!! More fun factor for sure!!! Now I just have to get a new tire so I can hook up!!!
 

canyncarvr

~SPONSOR~
Oct 14, 1999
4,005
0
Try your air screw @ 2.5 out. Adjust by no more than 1/16 (20º or so) on either side of that. Let each adjustment run for a bit before trying another. Look for perfect off-idle response and an increased pull in 3rd gear from1/8 to 1/2 throttle.

re: head done
You'll like it. It would be nice to do such things one at a time. You won't know which change is having what effect.

But you will like it!
 

Tom L

Member
Dec 18, 2004
143
0
Thanks CC!!! I'll have to do some sperimentin' with the air screw. I just turned it in to get rid of the hesitation as I thought that was the only thing you can do to cure it. I'll try it at 2.5 to see what happens. I figure when I do the top end next winter, I'll send Ron the head for additional boost!!!
 

canyncarvr

~SPONSOR~
Oct 14, 1999
4,005
0
Click HERE for a bit more info.

It's touchy out that far. It also has a large impact on how the bike runs. With one'a RBs knurled screws it's easy to adjust. You will find yourself making those 'easy' adjustments maybe several times a ride to compensate for temp and el. changes.

Since the above link was written, a few more riders have found that SSS (is that Second Sweet Spot?). There have also been a number of riders that didn't spend much time looking for it, yanked the AS around 1/4 turn at a time...came to the conclusion there was no such thing.

Oh well! ;)

Find it. It's worth it.
 

ABS13

Member
Apr 15, 2004
16
0
I see most of you guys are 200 pilots. Does the "SSS" exist the same for the 220? Seems like the RB mod would make both bikes behave pretty much the same - correct?
 

Top Bottom