KDXRIDER.NET

Hey all i know this has probably been asked time and time again but im having a bit of a problem with my 99 KDX200 carboning the plug up. I amcurrently running:
Iridium Plug
FMF gnarly pipe and fmf shorty muffler
V force reeds
Bored and jetted carby
upped compression
k&n filter
airbox mod

Now it sorta wasnt doing it before but now is. i run a 40:1 ratio of motul 800 factory (may be too rich i think) but i do heaps of different style riding, from street putting around to open flats full throttle racing.

Basically just wondering how to stop this mass carbon buildup with the different riding styles. (slow off band street use to full band all the time)

Thanks for your help in advance people.

Neesmo31

First... get rid of the iridium plug and use a NGK BR8ES. Next would ditch the K&N filter for a good foam element. And lastly, jet it!

It sounds like you went out looking for the most expensive parts, but that does not translate to good performance on the KDX.

Thanks for that. Yeah its been jetted. Yeah thats just how i bought it. ive only had it for bout 4 weeeks. I also have just bought a hiflofiltro foam element for it as i think they offer better filtration than the k and n.

Anyone can "jet" a carb but that doesn't mean its going to be ideal. If you post up the jetting that you currently have in the carb (main, pilot, slide and needle) and what your temp and elevation are we can tell you if the jetting is in the ballpark.

The person i bought it off used to be a motorcycle mechanic for years up here and when i picked it up off him the plug was a nice coffee colour.

i might tear it down next week for a good clean and grease and a serice and ill check those carby specs for you. also we live on the beach so i think elevation would be nil.

thanks again for you help.

Today after a ride it doesnt sound as "tingy" as it used to be if that makes any sence. It used to ting ting ting pretty noticeably before and it sounds a bit dull now. Another thing is that the kips used to kick in pretty noticeably as well but seems to almost fade over from low end to top now. I think all the kips might be carboned up as well.

Another question is how to remove carbon deposits form the expansion chamber - ive heard you heat it red hot and then dowse it in water and they deposits crack off. am i correct??

Any help to this carboning issue is much appreciated.

Thanks again all.

It sounds like your silencer may need to be repacked...that would affect the sound and power loss you're experiencing.

Re: upped compression

What does that mean?

Your head could be machined/cut in such a way it will never work the way it's supposed to.

What was done to it? The term (upped compression) doesn't mean anything by itself...and anyone that describes their machine work only as having 'upped compression' would be a matter of concern.

A 'dull' exhuast note..sounding like it's down inside the pipe is a sign of a too-rich setup.

And, what's a 'bored and jetted' carby? This came from RB? If you posted that info someplace else...I didn't go looking for it.


For the sake of clarity, don't mix up premix and air/fuel terms:

' i run a 40:1 ratio of motul 800 factory (may be too rich i think)'

I presume the 'too rich' of that is a reference to the premix ratio..but the term 'too rich' generally applies to air/fuel.

Repacked the muffler today with stainless wool, souds a bit better, and to answer your questions i think he machined the head slightly and the carby was actually bored out, had it off today and cleaned it out but forgot to get the needle specs. took if for a good thrash today and it has seemed to clean itslef up a bit, plug is a nice brown coolour. i tihnk it was because i ran the foam element air filter back and forth to work last week and it gummed up, but k&n back on and a good thrash and it seems to have recified the probloem.

Steel wool for packing! Oh my!

There are about eleventy-dozen things off a good bit about a number of things you mentioned, but if it has all worked out to suit you, that's good!

I used to use steel wool for starting campfires with my hot spark kit. That wasn't stainless though. Does the stainless make it not able to smoulder? If not, I would think steel wool saturated with oily spooge would be just the combo to make repacking chores a thing of the past!

Mostly because of the jail time resulting from littering the center of a burnt out forest with the remains of a KDX.

Neesmo31 wrote:The person i bought it off used to be a motorcycle mechanic for years

Which basically means diddle

Steel wool used for packing is supposedly a good bit LESS fine than your basic cleaning/polishing 4-0 stuff..still, it'll burn. Less in a 2T due to the oil and lower exhaust temps...but it'll burn. Some aftermarket exhaust pieces come with SS wool packing, I've read.


Re: '...burnt out forest...'

This part, '..fmf shorty muffler ..' would seem to make it clear that's not a concern.

In the world of bored carbs (I wonder what was done to the jet-block as a result of that?), and 'shaved' heads (squish anyone?) it's all good!

huh, never heard of that. thanks for the info.

Which part? SS wool for packing?

There's a few threads on TT about it..ADV, too.

yeah, I never heard of steel wool in a silencer. I'll go stick my head back in the dirt.

Well, move over!! I hadn't, either. Sounds like a great way to start a fire to me!

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Hey! There's worms down here!!!!

Yeah its no where near as dense as the fiberglass packing that i pulled out of it, another plus for the satinless is that it can be degreased and cleaned to a certain extent. Its not how you would think of steel wool, its very very fine wire that is sparse (if you can understand that lol)

On a lighter note the bike seems to be running really well now. gave it an absolute hiding last weekend and its seemed to clear itself out a bit, i think i may have over oiled the filter the first time and i was just putting back and forth to work which clagged it up. But a tank full of throttle seemed to clear it out and the plug is showing a nice brown colour now with no carbon deposits.

Also the reply about the jet block, it protrudes just out of the main barrel in the standard location.

Im not trying to tell anyone about my bike and how good it is with these mods, just trying to understand the 2 stroke side of things and get some information from you guys to try and help me understand it all. I appreciate the help to everyone - so dont flame me!!! lol first time KDX (or 2 stroke for that matter) rider!

Thanks all for your help.

Re: 'Also the reply about the jet block, it protrudes just out of the main barrel in the standard location. '

I wasn't asking for a description of what it looke like. My point was that to bore a carb, the jetblock has to be removed. Fine...except that when you put it back IN...well, it ain't gonn'a fit the same, is it!

I understand what the SS stuff is you're talking about. Used to be there were dishwashing 'pads' made of it..kin'da like a Tuffy made out of SS flat wire.

Good to hear your bike runs to suit you! That's always a good thing.