RB mod curious

[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?

[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.

[sped66]

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.

[Indawoods]

Wrong folks to check out your 220... IMO.

[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.

[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

[sped66]

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.

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.

[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]

[Indawoods]

Yeah... something is wrong... that should have been easy...

[Mr. Wibbens]

Yup sumpthin is wrong

[ihatefalling]

+1......my 220 crawls like a champ......sorry I dont know what could be wrong

[fuzzy]

Sounds like your KIPS are open maybe....along what wibby said. Also check condition of reeds.

[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...

[Mr. Wibbens]

Go look at the video at Youtube and see who made a comment

[Julien D]

haha, awesome.



I agree with carvr. Looks like somethings up. I'm betting power valves.

[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.

[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.

[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.

[Indawoods]

That is correct...

Just get the online manual at the top of the page.... so much easier.

[sped66]

That is correct....

Thank God. And thanks for the quick reply! I'm off to inspect the reeds & carb now.

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.