Idling & Riding / Choking

[exilestudios]

In order to ride my KDX I've had to choke it otherwise it bogs out when I get on the gas. However, in order to have it sit and idle I have to have the choke off. This confuses me and I'm just wondering if something is wrong or is it okay to just run it this way. I'm thinking either my carb needs adjusted a particular way or it's just the fact that I'm up on a mountain with a high altitude and it's been kind of chilly out. I was thinking if it's something to do with the temperature wouldn't it be fine after the bike is warmed up? If so then this cant be the case because it was still doing the same after riding for a while. I don't know, but I thought I would get some opinions from you guys. Thanks.

[diymirage]

i would start by tearing the carb apart and giving it a good cleaning
what you are describing is not normal and could be caused be a blocked jet or passage

your altitude should only affect a bike which has been properly jetted for a different altitude
(if you jet a bike at sea level and take it up there the altidude will affect it but if you take your neighbours bike and jet it properly it should be fine for where you are)

the cold could affect it a little but i dont think it would cause as much issues as youre describing


like i said, give her a good cleaning and see what type of jets you have in there right now
then see if there is any improvement and if there is go through the steps of properly jetting here

[exilestudios]

i would start by tearing the carb apart and giving it a good cleaning
what you are describing is not normal and could be caused be a blocked jet or passage

your altitude should only affect a bike which has been properly jetted for a different altitude
(if you jet a bike at sea level and take it up there the altidude will affect it but if you take your neighbours bike and jet it properly it should be fine for where you are)

the cold could affect it a little but i dont think it would cause as much issues as youre describing


like i said, give her a good cleaning and see what type of jets you have in there right now
then see if there is any improvement and if there is go through the steps of properly jetting here

Well, I cleaned the carb when I first got it, because I think the float was stuck or something. It would just drain the gas before I did so. Though I'll try cleaning it again and maybe a little more thoroughly. However, in the mean time will it do much harm with me riding it the way I am? I'm kind of addicted to riding it. :P

[bufftester]

The idle circuit is separate, and apparently working fine if it idles no problem. Likely you have a blocked main or a blocked passage, pulling the choke just dumps more fuel aft of the slide. Bogging means lean, sputtering is rich. Start here and make sure you have clean filter, good plug, new gas. As far as damaging your bike, running overly lean can lead to seizing the piston, not a fun or cheap experience. I'd recommend getting it straightened out first.
Jetting Guide:
http://kdxrider.net/forums/viewtopic.php?f=105&t=1156

[exilestudios]

The idle circuit is separate, and apparently working fine if it idles no problem. Likely you have a blocked main or a blocked passage, pulling the choke just dumps more fuel aft of the slide. Bogging means lean, sputtering is rich. Start here and make sure you have clean filter, good plug, new gas. As far as damaging your bike, running overly lean can lead to seizing the piston, not a fun or cheap experience. I'd recommend getting it straightened out first.
Jetting Guide:
http://kdxrider.net/forums/viewtopic.php?f=105&t=1156

Thank you very much. I will do so.

[exilestudios]

Well I've been fiddling with it the past couple days. Today it's a bit nicer outside, so I was just out messing with it some more.

The day before yesterday I pulled my carb and tore it apart spraying everything out with carb cleaner. I put it back on the bike and hadn't had much more luck.

Yesterday, I pulled it back off and decided to venture into territory I hadn't messed with before and pulled the pilot jet and the main jet. The main jet was fine could see clear through it perfectly fine, but the pilot jet was practically impossible to see through and some of the holes had crust in them on the bottom of it. I got a really really fine needle small enough to just slip through the holes without reaming them out any and cleared all holes in it. I put it all back together and put it back on my bike. It still acts the same.

I've tried adjusting the air screw and idle screw in countless ways. With the idle screw adjusted to a low idle before the bike cuts off and the air screw turned all the way in it runs without the choke on, but still acts like it's going to bog when I'm in 2nd gear or higher and start to hit a slight hill.

Correct me if I'm wrong, but based on my researching I did yesterday I need a bigger pilot jet, determined by the need to have the air screw in less than 3/4 turn. Does this sound right to anyone else? If so I guess I'll be investing in a jet kit.

Also, I don't know if this has been shared here or not, but I've found it to be very useful and informative about the carb's workings. http://www.e-dirt.co.za/site/forum_posts.asp?TID=37772

[bufftester]

Does sound like you need to go up a size on the pilot jet to get started. I guess we weren't very clear about cleaning the carb. You want to disassemble it completely, slide out, jets out, vent tubes off, float and needle valve removed. Then take the carb cleaner with the little tube and blow out every single hole you can find. regardless of where you shoot carb cleaner in, it should come out some other hole (thats how you'll know if you have a blocked passage. Dont forget to clean the top of the slide where the cable connects too, lots of gunk can build up there. Once that is done reassemble and then start with the jetting guide. It's a PITA, but worth it once she's running like a top.

[exilestudios]

Does sound like you need to go up a size on the pilot jet to get started. I guess we weren't very clear about cleaning the carb. You want to disassemble it completely, slide out, jets out, vent tubes off, float and needle valve removed. Then take the carb cleaner with the little tube and blow out every single hole you can find. regardless of where you shoot carb cleaner in, it should come out some other hole (thats how you'll know if you have a blocked passage. Dont forget to clean the top of the slide where the cable connects too, lots of gunk can build up there. Once that is done reassemble and then start with the jetting guide. It's a PITA, but worth it once she's running like a top.

Alright. Thanks a lot guys!

[rbates9]

What do you have for jets right now? I would start with a size up like you said and see what that does. Also when starting to jet it doesn't hurt to start with new jets just so you know that the po didn't open the jets up and you will know they are clean and the correct size. If you have to travel to get new jets I would get a new one and a size up and down from what you think you will need. It is a pain to get started on the jetting and have to stop because you don't have the right size jets. And when it warms up you may have to go down a size with the jets to keep it running right. Temperature can play a huge role in jetting so if this would be your normal off season and your riding season will be much warmer you may want to get close now and then fine tune when the whether comes around.

[exilestudios]

What do you have for jets right now? I would start with a size up like you said and see what that does. Also when starting to jet it doesn't hurt to start with new jets just so you know that the po didn't open the jets up and you will know they are clean and the correct size. If you have to travel to get new jets I would get a new one and a size up and down from what you think you will need. It is a pain to get started on the jetting and have to stop because you don't have the right size jets. And when it warms up you may have to go down a size with the jets to keep it running right. Temperature can play a huge role in jetting so if this would be your normal off season and your riding season will be much warmer you may want to get close now and then fine tune when the whether comes around.

I'm not sure what jets are in it right now, but I'll take a closer look when I pull the carb again. I was considering ordering a jet kit from this eBay seller when I get the money. This is my off season, but thankfully the warm seasons are starting to roll in. I took my KDX down the dirt road today to the river and it seems to run well, all but the bogging I've mentioned. It seems to be fine when going through the gears hitting the rpm for each gear, but like taking off from being at a stand still or being in a too high of gear when going up a hill and dropping speed it starts to bog. Though for it to even run this decent I had to have the air screw all the way in, so the jetting definitely needs changed. It's hard to resist the urge of wanting to ride it, but I also don't want to mess up the new piston I recently put it in. Though, I'm not riding it too awful much, I still want to get it taken care of. I would also like to get some opinions about that jet kit eBay listing and if you guys think it'll be what I need or should I be looking else where. They say to note the year and model and such when purchasing it, so they can customize the kit to the bike.

[rbates9]

I am going to say that the ebay carb kit would be a waste of money. They talk about putting in larger jets and the KDX comes too rich to start with. I can't speak for everyone but I would guess that about 90% or more of the people on here are using smaller then stock jetting. So the kit would be heading in the wrong direction. And anyone that gives jetting advise from a distance should be taken as advise and nothing more. You could do the same things to two of the same bikes and they would both be a little different.

Jets tend to run between $3-$5 so the $50 that you will spend on the kit could go toward a lot of jets.

See what you have in the carb now and post it up. We may be able to give you a nudge in the right direction but only you can find out what your bike needs where you ride.

[exilestudios]

I am going to say that the ebay carb kit would be a waste of money. They talk about putting in larger jets and the KDX comes too rich to start with. I can't speak for everyone but I would guess that about 90% or more of the people on here are using smaller then stock jetting. So the kit would be heading in the wrong direction. And anyone that gives jetting advise from a distance should be taken as advise and nothing more. You could do the same things to two of the same bikes and they would both be a little different.

Jets tend to run between $3-$5 so the $50 that you will spend on the kit could go toward a lot of jets.

See what you have in the carb now and post it up. We may be able to give you a nudge in the right direction but only you can find out what your bike needs where you ride.

After what I discovered today, I'm beginning to think there's nothing wrong with my carb after all...

Since I've gotten my bike back outside to ride I've had some slight trouble with the clutch. Even though I put an entirely new one in it. The clutch lever has spun too far around on me twice, but if I don't have it adjusted how I adjusted it then it didn't seem to engage all the way. Well...when I first took it out to test run, even with the clutch pulled it seemed to drag. After a while this seemed to work itself in, but I was still suspicious about it.

Yesterday was when the clutch lever spun around on me for the second time. Today I drained her down and took the clutch cover off again to put the clutch lever back to the way it should be. Out of curiosity I decided to pull the whole clutch out again. What I found made me face palm like 20 times and made me feel like a jackass. The back of the clutch basket had been rubbing against the washers that are holding the big ass bearing in there. Apparently I had missed one spacer when putting my clutch back on. This makes sense as to why it was acting like it was dragging with the clutch engaged when I first took it out to test run after working on it. I am also thinking this might be why it seemed to bog so badly when taking off and when the rpm was dropping in a higher gear. Everything in relation to this still seems to be fine though and should be in working order. However, this is just the start of my concerns though.

I found a piece of metal laying in there below where the clutch would be sitting. There's nothing in that side that it looks like it came off of. I am hoping it's maybe a piece of metal from when the previous owner had ragged the hell out of it and the tranny happened to spit it up or something. Though it worries the hell out of me and I'm thinking maybe someone here could help identify what it might have snapped off of. Below is some pictures of the piece of metal I found. May I note again, there's nothing on the clutch side that looks damage or that looks like this may have came off of it. The only damage done is some slight grinding down on the washers, which hold the bearing in, but I spun those around so the grinded side is opposite of the side that is actually holding the bearing in.

Hopefully someone can help enlighten me, as to what this piece snapped off of and how concerned I should be. I would really hate to have to tear anything more back down. The gears shifted smoothly when I was riding it, so I don't think its anything down in there. I just don't know . It'll be parked for now though. We have some snowy weather blowing in, so I'm not too heart broke about parking it for now because I wouldn't be out riding anyways. Though I am still worried about where that piece came from and what it might affect if I were to put the clutch back in and just ride on.

[exilestudios]

Hm...I'm thinking it might have snapped off of the lever-comp. Though I am not 100% sure. Looking at the picture of the lever-comp and the smooth edges of this piece of metal, it seems it might be a chunk out of it. However, I would still like someone else's opinion.

[rbates9]

The pictures didn't come out that clear nut if you remove the right side cover you will be able to see the governor lever and see what shape it is in. But if you really think that the piece is from the lever and the lever in the bike is good then you will need to look for the rest of the old one. Or you could go with the hope for the best route. I would probably look for it if it were me.

[exilestudios]

The pictures didn't come out that clear nut if you remove the right side cover you will be able to see the governor lever and see what shape it is in. But if you really think that the piece is from the lever and the lever in the bike is good then you will need to look for the rest of the old one. Or you could go with the hope for the best route. I would probably look for it if it were me.

Yeah, I'll probably end up looking, but the worst part is that gasket for the right side cover costs more than that little lever. And I recently replaced it and sealed it up good sadly. The clutch cover I only sealed up one side of the gasket because I suspected I would probably end up having to pull it back off again, but the whole side cover's gasket I sealed up both sides of it. Also it was hard to really get a clear pic of the piece because of how small it is and if backed away to where it was clear it was too small in the pic to really see it. Thanks for the responses you've been a great help. Also, could the washer/spacer being missing from behind the clutch basket and it rubbing be what was causing the bogging or do you think it is actually the pilot jet in the carb?

[rbates9]

1. You shouldn't really need to use a sealer on the gaskets. Just make sure everything is clean when going back together. Many people even use grease on one side of the gasket so when they need to remove it down the road they have a better chance of reusing the gasket.

2. I would take a real good look at the clutch assembly when you put it back together. A lot of times the parts break down pictures will help more then the manual will. Not that you don't need the manual.

3. It may be best to get one issue sorted out before you jump to the next. Good find on the clutch problem. When you get that back together then see what it does. It may have been the clutch causing the problems, or you may have had a few problems. Just stick with it and you'll get it figured out.

When you get the bike back together and ready to go you will know if the jetting needs work. Most likely it will but you will have to see.

[exilestudios]

1. You shouldn't really need to use a sealer on the gaskets. Just make sure everything is clean when going back together. Many people even use grease on one side of the gasket so when they need to remove it down the road they have a better chance of reusing the gasket.

2. I would take a real good look at the clutch assembly when you put it back together. A lot of times the parts break down pictures will help more then the manual will. Not that you don't need the manual.

3. It may be best to get one issue sorted out before you jump to the next. Good find on the clutch problem. When you get that back together then see what it does. It may have been the clutch causing the problems, or you may have had a few problems. Just stick with it and you'll get it figured out.

When you get the bike back together and ready to go you will know if the jetting needs work. Most likely it will but you will have to see.

I got the side cover pulled off today. It was that little piece that snapped. I'm not quite sure where that piece went. I have the piece that I pulled out that was laying on the bottom and the piece that was screwed to the rod, but that little rod that is part of the whole piece is MIA. Hmm. I'm almost thinking this piece might have been broke from when I first got the bike off craigs list. I don't recall ever seeing the little rod on this piece when I took off the side cover for the first time this winter, but I also didn't pay particular attention to it. I think it was just flat and it happened to just snap off the rest of the way...I can hope at least...would suck to have that piece lost down in the motor some where. Another possibility is that this was broken when I got it and it happened to spit this piece up that I found, rather than it breaking off more recently. Anyways, I'm glad I at least figured out what it was and it's an easy fix and cheap to replace. I am however concerned where that little rod from the piece might have gone, but we can be hopeful I guess...

[bufftester]

yeah, if it were me I'd probably end up looking for the remaining pieces, that small rod could wreak havoc if not located or accounted for. IME going the hope for the best route always lands me stuck in the middle of nowhere I'm assuming you never really got a chance to ride the bike hard and get up in the RPMs to bring the KIPS into play, otherwise you might have found this sooner. Of course, this doesn't really help with the original issue, but thats part of the fun of used vehicles...uncovering the breadth of abuse they've survived through already

[rbates9]

I would keep looking for the rest of the broken part. At very least you should go fishing with a magnet in the transmission for the rest of the pieces.

[canyncarvr]

Did I miss someone saying why that part broke?

It is most likely the result of taking the top segment gear off (LH threads!) the governor rod without supporting the shaft of the rod. It is a common mistake. The resulting pieces have grenaded motors before. By 'grenaded' I mean busted cases.

Bog:

In order to ride my KDX I've had to choke it otherwise it bogs out when I get on the gas.

Did I miss someone asking what '..get on the gas' means?

IF it means a quick flick to WOT from a slow pace (walking+), that is also a common error in tuning related to pilot jet size or AS adjustment, and I'll bet'cha MOST KDXs do it.

NOTHWITHSTANDING a number of other things that will cause similar problems.

Like...if the pilot jet had gunk in it, would you not expect the pilot mixure passages (air and fuel) to be gunked up, too? Carb spray won't likely take care of that. The carb body will need a good soaking and cleaning (bring on the piano/guitar string).


Good luck! Your bike has more than one problem. Keep after 'em..you'll get it up to snuff.