RB AS Carb - Out of the Box Report

Questions and Answers about the best carb and Head mods available for the KDX.
Post Reply
User avatar
Goat
Supporting Member III
Supporting Member III
Posts: 720
Joined: 03:22 pm Oct 22 2019
Country: USA
Location: Clinton, WA

RB AS Carb - Out of the Box Report

Post by Goat »

Holy Guacamole Batman! My KDX can scream like a banshee.
I might have to change my name to 'Green Rocket'.
Thank you all for the great info on this site.

I received my RB AS, last eve. USPS delivers here on Sunday nights!? (very strange this new world).
I plunked it on, bike fired on 2nd kick. After a little warm up and 1st gear perimeter check in the woods, it went out for a spin on the open road.
Hitting 60 in the pitch black at 9pm on a wet road is probably not the most intellectually appropriate thing to do, but man did it feel good.
Lucky for me I use only the finest in safety gear: Carhart hickory shirt, combat boots, Tusk one-size fits all street legal kit, $25 universal headlight, & the always reliable DOT knobbies. What could possibly go wrong?

The out of the box set up more than fixed what I was hoping it would.
I now have hella top end, that is better than I deserve.
Putting 190lbs on a 200, seemed like a stretch even for a bike with KDX-rep.
Even after 3 months of reading old posts + some pretty good luck keeping with the KTMs in the tight stuff, I still had guarded expectations of what this 'beginner' bike should be able to do on the top end when stet up right.
Wheel lifted in 3 gears..... 3rd was really more of a small boost than a lift. But, I am impressed.

I agree with whoever made comparison description:
RB carb feels kinda like a staggered 2bbl with 2ndary opening after the slide goes past the divider plate.
It seems to absolutely scream below and above the '2ndary line'.
First impression: All you have to do to go like bat out of hell with almost instant throttle response, is pick a gear that doesn't sit on the transition point.
But never having had one of these stock, maybe that is how the OEM carbs feel also. I am not sure I would know the difference between 2T hit and divider plate transition.

My 200 came with very nice but all stock 35mm AS, (MJ-160, PJ-48) that did great things on bottom but would not rev out well, I had to wick wicking it to work it up. Felt like I had to use the throttle to add air rather than gas. The old posts here had convinced I'd need to try an RB at some point, even if I got this one to work well. So, instead of working through the jetting on stock AS, I took a short cut and purchased from Ron so I could spend carb time fine tuning on his, rather than maybe have to do it twice.

I think the extra $125 ($387 was my total) you pay for RB carb seems like quite good deal to get the bore & mod's + baseline jetting that works. Too bad I now have a perfectly good carb I don't need... oh well.

So far, so good....I highly recommend the RB AS.
Next rides, I will work on fine tuning and learning the airscrew tendencies then go hunt the SSS.
Great Stuff! He still has fast TAT.
I am a happy RB customer and will probably have a very nice unmolested 35mm AS for sale soon.
Goat
95 KDX200
22 KX250
User avatar
Molly's 70
Platinum Member
Platinum Member
Posts: 563
Joined: 04:29 pm Jun 18 2017
Country: USA
Location: Wichita, Kansas USA

Re: RB AS Carb - Out of the Box Report

Post by Molly's 70 »

Did you have him do the squish band on your head?
If you lend someone $20, and never see that person again, it was probably worth it.
User avatar
Goat
Supporting Member III
Supporting Member III
Posts: 720
Joined: 03:22 pm Oct 22 2019
Country: USA
Location: Clinton, WA

Re: RB AS Carb - Out of the Box Report

Post by Goat »

No. I just bought the RB Carb. I do not know if any head work has been done by prev owners.
Goat
95 KDX200
22 KX250
User avatar
doakley
Gold Member
Gold Member
Posts: 1241
Joined: 02:58 pm Mar 10 2016
Country:

Re: RB AS Carb - Out of the Box Report

Post by doakley »

Really good to hear. I haven’t installed my RB OEM style yet as the bike has been stripped for suspension service, bearing replacements, new practical, etc. “Between seasons” stuff waiting for next yrs racing!
User avatar
Goat
Supporting Member III
Supporting Member III
Posts: 720
Joined: 03:22 pm Oct 22 2019
Country: USA
Location: Clinton, WA

Re: RB AS Carb - Out of the Box Report

Post by Goat »

That sure looks like a sweet ride! Good luck with carb and another podium race season.
I’d be really curious in your RB comparison to a well-tuned OEM carb.
My swap was kinda cheating, since the jetting in my original AS carb had never been tuned well.

I am also one of the proud Kawi 175 Enduro Clan (1975 version). I was so proud of that green machine I could bust.
After learning to ride on the yellow Kawi 100, and getting my *** handed to me by my elder cousins on their SL250s, it was nice to keep up, sort of. I never came anywhere close to catching up in riding skill before they aged out from hanging around with me.
Please give my best to brothers at Cherry Pt, if you are near the coast.
Goat
95 KDX200
22 KX250
Post Reply