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Questions and Answers about the best carb and Head mods available for the KDX.
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canyncarvr
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Post by canyncarvr »

A btw..but there isn't (that I know of) a bonafide reason for this adjustment's existence.

It does seem to be a matter of synergy between the slow and other carb circuits. Because it's not the 'norm' regarding the slow speed circuit, because it's outside the bounds of what is generally considered 'correct' tuning, it is likely scoffed at.

..but only by those that don't have an RB modified carb..and if they DO have one, they haven't taken the time to TUNE the thing!

I've found it to be more 'fuel screw' like than 'air screw' like. When the temp drops during a day's ride and my bike's performance noticeably changes (drops), I turn my air screw out an indicator-width or so..and I'm right back 'on' the SSS.

'Normally', cooler temps would see the air screw going IN..not OUT.

Thus..it's like a fuel screw on a 4-stroke carb.

Can't say as I care as to the explanation and/or whys and wherefores of the whole thing. I know it's there. That has been vetted by other riders..again, both 200/220 riders.

Kind'a like using toluene. I know it works. Anyone that wants to snicker about it..thinking that use of toluene is just hooey is more'n welcome to think whatever they like.

Don't care about that, either! :wink:

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Post by Jeb »

Hey Crazybrit, I have a 220 and my setup is very much like yours including the Wiseco - I can state that the change was UNMISTAKABLE. It'll take a little time, but I'd check the install on those reeds just to make sure. If that turns out OK you might consider pulling the head off and noting the direction the arrow on the piston crown is pointing - should be pointing toward the exhaust.

I know those seem like obvious things but something's up. My experience: even if the carb A/S needs a bit of adjusting you should STILL note an obvious change.
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Post by crazybrit »

>|<>QBB<
Jeb wrote:Hey Crazybrit, I have a 220 and my setup is very much like yours including the Wiseco - I can state that the change was UNMISTAKABLE. It'll take a little time, but I'd check the install on those reeds just to make sure. If that turns out OK you might consider pulling the head off and noting the direction the arrow on the piston crown is pointing - should be pointing toward the exhaust.

I know those seem like obvious things but something's up. My experience: even if the carb A/S needs a bit of adjusting you should STILL note an obvious change.
I put the piston in the correct way ;-) I must acknowledge the amazing amount of help Ron gave me. I was a bit nervous about the whole thing but it was actually easy and the help and advice he gave me was very reassuring.

I read a post by CC saying that the manual was wrong wrt the subport valves, that gave me a heart attack for a second but my manual must have been reprinted (9th ed may 20 2005) as it matches his description. Taking the cover off, I can see the left KIPS side gear rotate and the rpms rise, not sure if this means it's all working ~shrug~

I guess finding someone local with the same bike would be interesting, riding Friday with a guy with a 200, stock I believe. I'll be curious to compare against this. Not sure how valid that will be. Otherwise I might just have to finally meet that Carver dude. ~Ack~

I'll check the reeds. Pretty sure I installed them correctly. I noted the point about making sure they were flush/flat, else flipping over. They seemed flush. Is there anything else to check? I used the metal plates supplied in the kit removing the stock ones.

Unmistakable it was not. Alas
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Post by canyncarvr »

Ron is a great source of information AND help.

Well..don't take that has him wanting to be a personal tuner for everyone. :neutral: I'm not saying what he does/doesn't want (I have no clue..and I wouldn't speak for him or anyone else anyway)..I'm saying if I was him, I sure wouldn't wanna be the Encyclopedia Britannica all the time.

I digress...

There was a time there was a supplement in the front pages of the manual (like mine has) that corrected the earlier printed KIPS error. CDave's site used to list the error correction (checked..still there). I asked a Kawi rep about it..he told me they weren't going to bother with reprinting the manual..figured the supplemental correction to be fine. I have no way of knowing how old your manual is. That you just bought it don't mean nuthin'. 'NOS' very much applies.

The Boyesens are very straightforward install-wise. It would be hard to mess them up.

I vote for erased memory banks!

:shock:

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Post by Jeb »

Admittedly my suggestions were sorta' shots in the dark - and BTW I didn't intend on sounding indignant, insulting, or anything like that because the comments were simple things (and I had nothing better to offer and felt like I should try) - but it's a bit baffling that a big gain wouldn't be noticed after the changes.

I've been impressed enough with the results that the temptation for even more overwhelmed me, so I bid and won another head on Ebay and have sent it to Ron for some "you need race gas" work. I'm thrilled with the anticipation; 'got my first "mix" set to go already.

Memory banks? 'Mine are pretty much shot but I still remember the smile I felt break over my face when I scooted down the driveway for the first time with the mods. So . . . what were we talking about?
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Post by crazybrit »

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Jeb wrote:BTW I didn't intend on sounding indignant, insulting, or anything like that because the comments were simple things (and I had nothing better to offer and felt like I should try) -
Sorry if I came over as in any way irritated, your comments were appreciated and perfectly fine. You have no idea what I've done.

I've lost track of the #times I've figured a problem by someone going back to the basics and helping me out.

I need to find the post where the guy had the blocked exhaust. I recall it was a few months ago as I read it and then was in Ron's shop and he mentioned it to me too. Couldn't find it searching.

How possible is this (stock silencer). I was thinking if it was restricted, it might not impact stock performance but could limit the improvements post all the mods. Or is this crazy talk?

I'll check the reed installation to be sure, what are the things that people mess up here?

Tony
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Post by crazybrit »

>|<>QBB<
canyncarvr wrote: The Boyesens are very straightforward install-wise. It would be hard to mess them up.

I vote for erased memory banks!
I checked the silencer (w/ compressed air, it's not blocked). Rechecked everything else. I checked the KIPS gears, I can see it move at raised rpms under the left side cover. My manual refers to the RIGHT side as having the o-ring and groove, I believe this is correct and therefore I put the KIPS together correctly.

Rode 50 miles at Browns Camp (1500-2100 feet elevation).

I learnt several things:

1) I'm too clueless for the RB Carb. I should have just put an FMF pipe on and rejetted. I'd read all about this killer mod but I'd never touched the jetting on the old bike, it just worked. Noones fault but mine.

2) Carb: needs attention. Either the float level is wrong or the valve is sticking, or the pilot is wrong. The bike would constantly stall whenever (going down hill) I'd slow down. This was frustrating. Adjusting the air screw made no difference to this.

I upped the idle speed, it still would stall, If I was close to a flat, I'd just coast. Then use wide-open-throttle to kick it into life (usually wouldn't start any other way). It would get going and settle into a fast idle (too high as I'd raised the idle speed).

Probably gained 800' during the ride and the idle speed would vary widely with elevation.

4) I tried doing what Ron suggested and start by _just_ looking for the sweet spot in neutral via blipping the throttle, making 1/16th adjustments from his start point, I couldn't tell any difference. If I screwed it all the way, I could and the idle speed would drop, but it didn't seem sensitive to small adjustments. Need to play more.

5) I hit reserve, or I think I did. Going up a steep hill but the motor starting racing like crazy which is the opposite of what I expected. Almost topped out in rpms but with no throttle. I killed it. Couldn't start it. Switched to reserve and jump started it down the hill at which point it seemed ok again.

6) I should look at gearing. Stock 13/47 currently. I'd never liked 1st gear, even in the stock configuration. Too abrupt in 1st. Friend rode it yesterday and felt same way, very hard to be up on the pegs in 1st as the power delivery was so abrupt. Easier to control sitting or just off the seat. 2nd and 3rd are much smoother and power is more controllable even though there is more power in those gears.

Tops out way early in 1st. Another guy had a 200 with a 240 kit, 14 tooth front sprocket I think (couldn't see a marking on the rear -- he's going to check for me) and his would rev out way way higher in 1st and the power was more controllable.

Mine feels like it's either bogging at the top of 1st gear, or totally gearing limited.

7) When we got back to camp, I used a stick to measure gas levels. I was 1 3/4" lower than the KDX200 with the 240 kit and he was riding much harder than I was.

Plug seems oil wet to me indicating I'm running too rich. Stalling would seem to be pilot, not sure if the main is whats causing it to bog out in 1st or if it's gearing. It's a lot better in 2nd and 3rd but maybe I'm just not reaching the equivalent point.
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Post by 2001kdx »

Your poor KDX :cry:
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Post by Wazowski »

So....how'd it go at Brown's camp??

Did you get rained on?

Going there next weekend, Saturday..trying out new MT16 rear 952 front.

Waz
Last edited by Wazowski on 10:44 am Aug 21 2007, edited 1 time in total.
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Post by Wazowski »

>|<>QBB<
Wazowski wrote:So....how'd it go at Brown's camp??

Did you get rained on?

Going there next weekend, Saturday..trying out new MT16 rear 952 front.

Waz
Nevermind...I read your report above. I didn't realize this went to two pages already!

Yousa tinkin maybe shuda mod'd the stock carby?

Waz
Last edited by Wazowski on 10:45 am Aug 21 2007, edited 1 time in total.
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Post by xagentman »

crazybrit

You are going to have to LEAN that bike. The combo of the FMF and the RB carb required me to drop the needle by one notch (as in, move the E clip up one setting) before i was able to get my bike to run correctly. If you have not tried that I would start there.. I was having similar problems with my bike just after the mod as well. Making the adjustment to the needle changed my world. you WILL notice when its right. Worst case, I live in Portland and would be more than willing to contact you and compare notes on the bikes. that might give you a baseline.

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Post by crazybrit »

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xagentman wrote:crazybrit

You are going to have to LEAN that bike. The combo of the FMF and the RB carb required me to drop the needle by one notch (as in, move the E clip up one setting) before i was able to get my bike to run correctly. If you have not tried that I would start there.. I was having similar problems with my bike just after the mod as well. Making the adjustment to the needle changed my world. you WILL notice when its right. Worst case, I live in Portland and would be more than willing to contact you and compare notes on the bikes. that might give you a baseline.

-Agent
Hey, thanks for this. I live 5 miles from Ron's place and he jetted the carb for riding here. He wants to look at the carb again, but I'll mention what you said.

Thanks for the offer, I appreciate it. I'm new to 2 strokes, so I really appreciate the advice, Thanks!!
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Post by KarlP »

Hey crazy-
I'm the guy with the blocked OEM silencer. Ron helped me out with that.
When I got the carb and head I put them on and the bike would not run worth a durn. I ended up with a 140 main just to get it to go.
I called Ron and between us we realized my stock silencer must be plugged up. I put on another one I had and the bike just RIPS.
Now, to be fair, I don't how long that silencer had been plugging up, certainly for years. The bike maybe would have RIPPED without Rons changes but with a clear silencer, but I don't think so. I remeber when I first got it and fixed the jetting I was thinking that the bike was kind of wimpy. It was, and is, compared to some. However, right now it is the best running two stroke I've ever owned. It's not a 250 MX'er, but it is equivalent to a 200 KTM or GasGas motor wise, maybe better if you like a little grunt.
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Post by xagentman »

Any news on this? did you get it resolved crazy?
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Post by crazybrit »

>|<>QBB<
xagentman wrote:Any news on this? did you get it resolved crazy?
Not looked at it. Was down in the State Of Jefferson last week on my KTM.

Maybe I'll take a look at it this weekend.
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Post by crazybrit »

So I took the bike out to East Fork Rock (central oregon) this weekend. My first time there. The bike ran pretty well. I was happy :grin:

I've been super busy and havn't ridden since the above. Tried three times to get back out to Browns Camp but work/life always got in the way.

Concluded it was running too rich before at Browns, only change I made was to follow xagentman's advice (who lives near me) and moved the clip up one position to #2 to lean it out a bit.

Elevation of EFR is 4400-6400' whereas Browns Camp is 1500-1800'. Odd as this would tend to richen things, of course it was cooler which will lean things out too. Clearly too many variables apples/oranges.

Still running a little too rich me thinks and it would still stall out if I went from on the gas to hard braking (avoid other riders/etc) or came to a sudden stop but it was way less frequent than before. Got really bad fuel economy though, hit reserve at 41 :-(

I doubt I'll be back at EFR for a while (man, the guys in Bend are lucky to have that area and Millikan, wow!!!) so I'll have to get the bike dialed in for Browns. Thanks to everyone for all their help, as I said before, I should have got more of a clue with the stock setup before upgrading but hopefully I can learn something here. Thanks to Ron too, sorry if I was the nightmare customer :neutral:
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Post by 80elkster »

Float Level Too High????
From the sounds of the posts above your float level may be set too high which would give you rich conditions and poor mileage.
So here are a couple of sugestions
First pull the carb and set the float level Here is a quote from one of the sites prolific writers, Also check your manual on setting the float level:
>|<>QBB<
canyncarvr wrote:I don't have my manual at work...but .....

A number of things you can find in other threads:

1. The float needle is spring loaded. If you followed the 'old' rule of turning the carby upside down and measuring where the float drops to..that is not right. That method will compress the spring. The correct level is set when the float just touches the pin, but does not compress the pin.

2. Be sure to bend the tang that touches the pin, not the float arms themselves.

3. Be sure the hinge pin is correctly in place when you put the float back on.

4. Take care to not change the float setting when you put the bowl back on. It's not hard to do...bend a float on bowl install I mean.

5. Make sure the carb downstream (reed side) tab is properly indexed to the slot in the carb boot. Having the carb just a tad 'off' will make it pee worse than 'normal'. That said, it IS fairly normal for a KDX to pee. Part of that is a bent/worn out kickstand...if it pees on the stand, that is.

6. Set the float level a tad low..like at least 17mm..maybe 18. You're still in 'spec', but on the low side.

7. You may need to clean the needle seat. That entails a strip of wet-n-dry on a cotton swab used to a burnishing effect on the needle seat.

8. If you can see any mark on the needle where it seals (trys to) to the seat...replace it.


Re: Is there another?

Yes. Set the float mold line parallel to the carb body when the tang (again) just touches the pin.

Re: revs without touching the throttle.

1. You took the carb out to set the level? Check the nylon (white) cable retainer on top of the slide. The tab in the retainer must fit in the slot in the needle holder nut.

2. That being OK, something is either considerably lean or plugged up.

Re: 'and I prefer to learn and do it myself.';

Great!! Have someone else do it and you will likely have to 'repair' it after they have 'fixed' it anyway. If you're going to ride a dirt bike and NOT do your own maintenance..you're in for a world of hurt! LOTS of $$ and LOTS of wasted time hauling to/from the 'shop'..and the aforementioned required repairing on your part.

Good Luck!!

Ask if you need assistance!! Aside for the occasional (VERY seldom actually! :shock: ) smart aleckedness from some on this site, someone here can likely answer most any question you have.

**caveat** SR model 220 (non-US) and early 'E' models too? Well...maybe... just possibly.... :neutral:
Second since you don't know (??) if the silencer has been cleaned and repacked you should head down the the cycle parts store and get some packing and repack your silencer.
Whether this helps or not you will at least know when these two maintanence items have been done. Repacking the silencer is an at least once a year task.
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canyncarvr
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Post by canyncarvr »

There is an answer to this..and you will be happy to find it.

Hope you keep looking. Something isn't right.


I only sped red the preceeding for a refresher..but I don't think this was mentioned: If you take your carb off, look into the boot attached to the cylinder...what do you see?

If you see any flat of the white phenolic air guide..it's in upside down. If there is any question about what you're looking at, stick your finger in there to ensure the egress of the boot matches the intake of the guide.

Or...take the reed cage out, turn it upside down from what it is, see what changes.

Yes, the 'packing' goes on the RH subport actuating rod. RH meaning the rear brake side. Well...front brake, too. I'm talking about brake levers.

The fact that you see the main rod turn by observing the nut under the LH slotted cover doesn't mean the KIPS is timed correctly. I've seen that (the rod moving) referenced a couple of times as having something to do with timing or proper KIPS operation. It doesn't.

If that rod does NOT move, obviously something is amiss. If it DOES move, it does not mean much of anything in regard to KIPS timing.

I'd like a better description of KIPS timing..and a look at the OEM reed block for verification of proper assembly for the purposes of making your bike run as well as it could.

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