Airlid Removal Only Mod

[_JOE_]

From what I have found in the kdx forums is that there is a definite bog caused by the complete airlid removal especially at sea level where it will run the leanest. Bikes seem to run lean here in Western Washington. The bog is when you are going at very low rpms and then wick the throttle pretty hard. My 1993 KX 250 never does that. I have read that a sharper tapered needle Like a DEK or CEK will make it much better but the bog will not go away until the airlid is reinstalled. Maybe I am too picky but I want the thing to run as close to fuel injected as possible. I think I will put the lid back on and call it good enough for the wife.

I'm with you. I'd rather have a silky smooth delivery than an extra pony or two.

 

[sr5bidder]

"The bog is when you are going at very low rpms and then wick the throttle pretty hard."

its not a four stroke, I usually have to feather the clutch or shift down to bring it up out of the "very low" rpm's to around 3-4k..

 

[meyaya]

I have a 1993 KX250 2 stroke that does not bog.

 

[domino dave]

'92 "E" model ... FMF, Answer silencer, Boysen reeds, 13/49, re-jet,no air lid ... flat out screams ... No bog! Even rolling (wick) from low R's ... not ever. No smooth delivery either ... just the way I like it! It's whatever trips your trigger. Dave

 

[julien_d]

Removing the airbox lid will cause it to be leaner if it's not re-jetted to compensate. Once you have removed the air lid and adjusted the fuel/air mixture to be correct, it should run better all around. Please do NOT expect to pop the airbox lid off and instantly have a better running machine. That's simply not going to happen, unless the jetting just happened to be off in such a way that removing the lid improves the overall tune. That is wholly possible, however unlikely.

That is my general experience on the subject, and I do what works for me. Get the most possible air flowing through the stock setup, and adjust the fuel flow to match it. Great results, every time.

Find a good jetting guide, and play with your jetting!

J.

 

[julien_d]

Removing the airbox lid will cause it to be leaner if it's not re-jetted to compensate. Once you have removed the air lid and adjusted the fuel/air mixture to be correct, it should run better all around. Please do NOT expect to pop the airbox lid off and instantly have a better running machine. That's simply not going to happen, unless the jetting just happened to be off in such a way that removing the lid improves the overall tune. That is wholly possible, however unlikely.

That is my general experience on the subject, and I do what works for me. Get the most possible air flowing through the stock setup, and adjust the fuel flow to match it. Great results, every time, on damn near ANY engine. Of course, leaving the stock setup completely in tact AND jetting it for that setup works perfectly fine too.

Find a good jetting guide, and play with your jetting!

J.

 

[Sandman 2.0]

For what its worth, I cut my lid leaving only enough to hold the electronic gizmo. I actually went down a size from stock jetting (Pilot and main) adjusted fuel screw and it runs great. No bogging, crisp throttle response. I'm about 800 ft above sea level. (2001 KDX200 with stock exhaust and silencer.)

 

[meyaya]

I finally have it running right. Airlid on with snorkel removed. 6 each 9/16'' holes drilled towards rear of airlid. 45 slow jet, 160 main and a CEM needle 2nd leanest position. It would not run right just off idle with a 48 slow jet no matter where the air screw was. Have read numerous reports about the 48 not working with the richer needles. It now may be too quick especially for my wife. I also have very little smoke or spooge. New spark plug looks slightly tan at bottom of insulator after plug chop. I will be adding an FMF gnarly woods pipe and turbine core silencer shortly. Last ride was 75 to 85 degrees. Elevation was 300 to 1800 feet.

Thanks everyone for all your help on airlid modifications and jetting.

Jeff

 

[samiam]

I wish I could find an airbox lid and snorkel. My bike did not have them when I bought it. I live in a very sound sensitive neighborhood and I have to do everything I can to reduce the noise.
Does anybody have one that they do not need or want?

 

[sr5bidder]

get a mountain bike ...I swear to God if they see a smile on your face they're gonna say something!! My lawn mower makes as much noise and my weed wacker but they are perfectly fine with that.... it's the fact that your are having fun that they can't stand I will take the mufflers of all my yard equipment and see if they like that f them

Luckly I don't live in a home owners association type n'hood hah

 

[samiam]

Well, I do not live in a HOA neighborhood, but I did once. It was a private lake. When it froze over, sleds could go 100+ MPH, as soon as I studded up a bike and hit 45, all hell broke loose, they had a meeting, and all motorcycles were banned (I was the *only* one that did this). Just like that. Sleds and ATV's were fine. I stood up to respectfully voice my opposition, and a neighbor threatened to break my knee cap with a baseball bat if I were to ride by him! No kidding!
To make things worse, that particular guy moved the following year, but the rule stuck. I moved shortly thereafter.
My current neighbors are decent folk. I just want to keep it that way.
Sorry for the thread hijack.

 

[glad2ride]

samiam, keep an eye on eBay.