RB mod curious

Questions and Answers about the best carb and Head mods available for the KDX.
User avatar
sped66
Supporting Member
Posts: 427
Joined: 11:29 am Oct 09 2010
Country: USA
Location: Near Winston-Salem, NC

RB mod curious

Post by sped66 »

Hi fellas... first post. (Lurker till now. I recognize some of you from TT.)

I used to have a '91 KDX250 & I didn't care for the bike as a whole, but loved the motor. I now have an '00 KDX220R & love the bike as a whole, but not so keen on the motor. Will the RB mods make this 216cc engine more 250-like? And I mean luggable/punchy to the n'th degree like my '91 was.

Relevant pre-existing goodies:
Gnarly pipe (How to tell if it's desert or woods?)
New FMF Turbinecore 2 - per Me
Reeds - yet to check model & make but appear to be brand new from the outside... (I know that likely doesn't count)
Fresh Wiseco - per PO with receipts
Jets - dunno yet, but cranks easily, runs well, no spooge

After two rides, ton o' fun bike with the throttle applied... but seriously bummed about no low end grunt. This thing couldn't pull a fart out of a greasy cat's a$$ at low rpm. Stall-city without clutch work when I hit the nitty-gritty. The KDX250 could climb a tree at darn near idle.

I'm able to spend the dough for RB if it'll give me back the lugness. Would it?

Image Image
In the stable: '00 KDX220R, '02 XR250R
Gone but not forgotten: '80 XR80, '87 XR200R, '94 KDX250, '01 YZ426F, '86 XR220R
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

That is not typical for a 220... something is up with your setup.

RB adds lowend and topend both.... but more low than high. Get the head done at the same time.
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
User avatar
sped66
Supporting Member
Posts: 427
Joined: 11:29 am Oct 09 2010
Country: USA
Location: Near Winston-Salem, NC

Post by sped66 »

>|<>QBB<
Indawoods wrote:That is not typical for a 220... something is up with your setup.
Maybe I expect way too much? I have a couple of buddies with KTM 2-strokes. I'll let them check it out & see what they say.
I'll likely have RB fix me up this winter regardless. Thanks for the reply.
Last edited by sped66 on 09:43 am Nov 11 2010, edited 1 time in total.
In the stable: '00 KDX220R, '02 XR250R
Gone but not forgotten: '80 XR80, '87 XR200R, '94 KDX250, '01 YZ426F, '86 XR220R
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

Wrong folks to check out your 220... IMO. :mrgreen:
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
User avatar
doctord23
Supporting Member
Posts: 323
Joined: 01:29 pm Jul 28 2009
Country: USA
Location: NorCal

Post by doctord23 »

Take off the pipe and the right side KIPS shaft cover, look in the cylinder and make sure the kips valves open when the KIPS shaft is turned clockwise and spring back to closed when the shaft is released. I had a KIPS stuck open and had the same lack of low end.
It is also possible that the valves were not re-installed correctly when the piston was done. The manual has an error in it that could cause you to swap the sub-valves to the wrong sides.
Last thing would be the jetting.

Oh and yes the RB mods help throughout the RPM range.
User avatar
Mr. Wibbens
KDXRider.net
KDXRider.net
Posts: 4884
Joined: 02:57 am Nov 07 2004
Country:
Location: Playing in the Poison Oak
Contact:

Post by Mr. Wibbens »

That poor fugger that went riding with us this summer had a 220 with the kips out of time. Thing had no bottom end at all
Warning! This member tends to use sarcasm as a regular form of communication. If a post seems offensive, before you panic and fly off the handle, re-read the post and imagine it being said with a sideways grin.
((Bike Profile))
((Pics))
FIVE OUT OF FOUR PEOPLE DONUT UNDERSTAND FRACTIONS
User avatar
sped66
Supporting Member
Posts: 427
Joined: 11:29 am Oct 09 2010
Country: USA
Location: Near Winston-Salem, NC

Post by sped66 »

>|<>QBB<
doctord23 wrote:Take off the pipe and the right side KIPS shaft cover, look in the cylinder and make sure the kips valves open when the KIPS shaft is turned clockwise and spring back to closed when the shaft is released. I had a KIPS stuck open and had the same lack of low end.
Thanks for the info. I hope to check this out tomorrow.
doctord23 wrote:It is also possible that the valves were not re-installed correctly when the piston was done.
Ugh.... I really hope this is not the case.
In the stable: '00 KDX220R, '02 XR250R
Gone but not forgotten: '80 XR80, '87 XR200R, '94 KDX250, '01 YZ426F, '86 XR220R
User avatar
sped66
Supporting Member
Posts: 427
Joined: 11:29 am Oct 09 2010
Country: USA
Location: Near Winston-Salem, NC

Post by sped66 »

I apologize in advance to the admin if this morphs into a troubleshooting thread. My feelings won't be bruised if the topic should move.

Made a very short vid in the hopes that you fellas might watch it and say "that's pretty much normal.... you ain't riding it right" OR "something is amiss, check stuff as suggested." I don't mind tinkering if I have to, but I'd rather ride than wrench.

[youtube][/youtube]
In the stable: '00 KDX220R, '02 XR250R
Gone but not forgotten: '80 XR80, '87 XR200R, '94 KDX250, '01 YZ426F, '86 XR220R
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

Yeah... something is wrong... that should have been easy...
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
User avatar
Mr. Wibbens
KDXRider.net
KDXRider.net
Posts: 4884
Joined: 02:57 am Nov 07 2004
Country:
Location: Playing in the Poison Oak
Contact:

Post by Mr. Wibbens »

Yup sumpthin is wrong
Warning! This member tends to use sarcasm as a regular form of communication. If a post seems offensive, before you panic and fly off the handle, re-read the post and imagine it being said with a sideways grin.
((Bike Profile))
((Pics))
FIVE OUT OF FOUR PEOPLE DONUT UNDERSTAND FRACTIONS
User avatar
ihatefalling
Supporting Member
Posts: 410
Joined: 09:30 am Jul 20 2008
Country:

Post by ihatefalling »

+1......my 220 crawls like a champ......sorry I dont know what could be wrong
2005 KDX 220
R&B Carb Mod
R&B Head Mod
Fork Swap - 99 KX125 Valved for B woods plush
FMF Gnarley
Airbox Mod
Tagged
User avatar
fuzzy
KDXRider.net
KDXRider.net
Posts: 3437
Joined: 01:29 pm Jun 18 2003
Country:
Location: Fredneck, MD

Post by fuzzy »

Sounds like your KIPS are open maybe....along what wibby said. Also check condition of reeds.
'91 KDX 200 Project $300 KDX
'95 KDX 200 Project $600 KDX
'94 WR 250 Always a project
KDX220rser
Member
Posts: 169
Joined: 07:56 am May 08 2008
Country: USA
Location: Louisiana

Post by KDX220rser »

yeah something way wrong... make sure when you put your Piston in you didnt mess up the Kips. I did at first with mine, i turned the little nobs like a DA...
09 KTM 250 XC-W
2005 KX-DX Hybrid
03 Ozark (under construction)
1978 Honda NC50 (under construction)
User avatar
Mr. Wibbens
KDXRider.net
KDXRider.net
Posts: 4884
Joined: 02:57 am Nov 07 2004
Country:
Location: Playing in the Poison Oak
Contact:

Post by Mr. Wibbens »

Go look at the video at Youtube and see who made a comment :wink:
Warning! This member tends to use sarcasm as a regular form of communication. If a post seems offensive, before you panic and fly off the handle, re-read the post and imagine it being said with a sideways grin.
((Bike Profile))
((Pics))
FIVE OUT OF FOUR PEOPLE DONUT UNDERSTAND FRACTIONS
User avatar
Julien D
KDXRider.net
KDXRider.net
Posts: 5858
Joined: 07:53 pm Nov 07 2008
Country: USA
Contact:

Post by Julien D »

haha, awesome.



I agree with carvr. Looks like somethings up. I'm betting power valves.
Image
User avatar
sped66
Supporting Member
Posts: 427
Joined: 11:29 am Oct 09 2010
Country: USA
Location: Near Winston-Salem, NC

Post by sped66 »

Ok I'm about to go check into this. If I have a valve that's "stuck open" is this just a matter of somehow freeing it? What's the procedure in this case?

Since the top end was done recently I'm betting the mechanic just got the valves in wrong. In this case, would it hurt the bike to ride it? I mean, I already have twice. :mad:
In the stable: '00 KDX220R, '02 XR250R
Gone but not forgotten: '80 XR80, '87 XR200R, '94 KDX250, '01 YZ426F, '86 XR220R
User avatar
kdxmaniac
Supporting Member
Posts: 595
Joined: 09:01 pm May 24 2010
Country:

Post by kdxmaniac »

it souldnt hurt anything.............the easy way to free the valve is take the cover off{left side} and turn the valve with the nut..........see if it moves freely.........if it dont, work the nut back and forth, not hard, but gently, and see if it start to free up............mine was stuck shut when i got it. i just done as i described, and spay a little wd-40 on the valve, and got it to working. now i can open the valve with the nut, and let go, and it will shut on its own..........

oh.......when mine was stuck CLOSED.........it run the opposite from yours.......had bottom end, but it would fall on its face when it hit the pipe.
my bikes
-------------
96 ktm 300
96 XR400R
07 hayabusa
77 kz 1000
85 goldwing 1200
02 BIG DOG PITBULL

gone but not forgotten
96 kdx 200
98 ktm 380 "because it dang near killed me!"
97 ktm 360
96 ktm 250
93 wr 250
94 dr 350s
93 kx 250
07 gsxr 1000
99 bandit 1200
User avatar
sped66
Supporting Member
Posts: 427
Joined: 11:29 am Oct 09 2010
Country: USA
Location: Near Winston-Salem, NC

Post by sped66 »

Thanks. I just came from inspecting the bike & I can turn the valve thingy with my fingers. A little stiffly at first but now pretty easily after working it a bit. I can see something in the exhaust port that has a "flapping" type motion when I twist the valve. I'm not exactly sure what closed or open is supposed to look like though. When I twist, the "flapper" goes up allowing me to see more of the piston. It drops towards the ground when I release. Is this correct or backwards??

Please forgive my ignorance. I'm only used to working on Honda XRs & have yet to pick up a manual for the KDX. :oops:
In the stable: '00 KDX220R, '02 XR250R
Gone but not forgotten: '80 XR80, '87 XR200R, '94 KDX250, '01 YZ426F, '86 XR220R
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

That is correct...

Just get the online manual at the top of the page.... so much easier.
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
User avatar
sped66
Supporting Member
Posts: 427
Joined: 11:29 am Oct 09 2010
Country: USA
Location: Near Winston-Salem, NC

Post by sped66 »

>|<>QBB<
Indawoods wrote:That is correct....
Thank God. And thanks for the quick reply! I'm off to inspect the reeds & carb now.
Indawoods wrote:Just get the online manual at the top of the page.... so much easier.
Sorry, didn't see that till you mentioned it. Will do!!
Thanks again.
In the stable: '00 KDX220R, '02 XR250R
Gone but not forgotten: '80 XR80, '87 XR200R, '94 KDX250, '01 YZ426F, '86 XR220R
Post Reply