Big Problem? Please help

gymrat86 · Jan 4, 2006

hey guys, today I took my 2003 KDX out trailriding and noticed that it acted like it was misfiring and there wasnt much power in 1st and 2nd and some of 3rd gear. when i got home i decided to check the spark plug. to my surprise after i pulled it out, it was completly black with some oily gunk/sluge on it. What do I need to do to get my bike running back like normal I just bought this bike used 1 week ago and now it is doing this. I hope this doesnt mean that I need to change my top end. Please help me out with this problem. Also when the engine is running what is it supposed to sound like? Mine kinda sounds like a knocking noise. I really hope this is not a major problem and hope that it is only my spark plug. let me know as soon as possible.

-Paul Graham

lepper · Jan 4, 2006

Sounds like it needs jetted.

Aaronkdx · Jan 4, 2006

the knocking is normal I heard the same thing with mine

lepper · Jan 4, 2006

It's more like a rattle... or should be....

gymrat86 · Jan 4, 2006

Big Problem

Yep thats the sound. Now what is going on with my power, I checked the compression on the engine and it is 90. Is this good or normal. I hope so . let me know
-paul

the trail rider · Jan 4, 2006

90 is about a 6:1 compression ratio. it should be anywhere with the kips closed 9:3 to 1 138-140 when kips is open 7.9: 1 on the 200 and 7.2:1 on the 220. around 110 on the 220 and around 120 on the 200

robl · Jan 4, 2006

As far as how it's running, you’re WAY too rich. Jetting may seem like science fiction, but once you understand it, it's not that bad. Do yourself a huge favor by reading the Carb Tuning page under the Engine heading on KDX Tech Tips. You may need to read it a couple of times, like me. If it’s jetted too rich, it can’t burn all the fuel/oil the carb’s dumping in there. The extra fuel is left everywhere (in the combustion chamber, crank case, pipe, silencer, all over your rear tire, swing arm, the rider behind you, ect)

For the most part though, there are three components to jetting. Pilot jet and air screw (throttle not open very far), needle and clip (throttle opened up a bit, like 1/2 - 3/4), and main jet ( throttle 3/4 to wide open). You're probably rich everywhere. I found that replacing both jets on the bottom of the carb with 1 size smaller, and moving the needle clip up 1 position on the needle should improve how your bike runs if it's gooping up like that. You will need to fine tune from there. Do some reading about it. The jets are marked with their size right on it.

The rattle is probably the KIPS valve. Mine is pretty noticeable.

As far as the compression goes, you might call a KAW. service shop and ask them what kind of compression you should read. If you want to know about your top end FOR SURE, take it apart and check the ring-end gap. Sorry, but that’s the only good way.

Again, probably one of the most important things about these bikes is jetting. If it's wrong, it will run like absolute crap and make you madder than a hornet. Once it's jetted correctly for where are when you are running it, it will run beautifully! It's a Jeckle and Hide thing really.

Rob

gymrat86 · Jan 4, 2006

Ok, I dont understand what KIPS is. All i did to measure compresion was take out the spark plug and put a meter up to it and then gave it a few kicks and 3 times it read 90. Is that good? I didnt understand any of what "the trail rider" said. Please explain it to me more I am new to this sport. Also I have a chance to buy a new stock carborator for cheap and was wondering if that would save me from all the hassel. One more thing, If I take off the cylinder head to the bike, will i mess up the gasket around it, If so where do I get another. Do you think I need to do a top end also. I have never had a dirt bike before and dont know much about them. Please help me.

robl · Jan 4, 2006

The KIPS is a power valve mechanism designed to provide good power down low (engine speed) as well as up high. Again, there is a tech article on the KIPS system on the Tech Tips web page on Canadian Dave's site. the trail rider is suggesting that your compression is to low. I'm afraid I don't know what you should be reading. How old is your KDX? If it hasn't had much use, you're probably fine. Is it a 220? Has the top end ever been done? If it's a 220, the stock piston will very likely break eventually. A common problem with the 220. Not a problem with the 200. Don't worry though, the top end is REALLY not a big deal on a 2 stroke. Very easy if you're comfortable with a wrench.

the trail rider · Jan 4, 2006

kips is the kawasaki integrated power valve system. it keeps your valves closed before 6000 rpms, the closed valves keep the compression higher. in turn before the valves open you have more compression and more low end on the bike. at 6000 rpms the valves open and give you more midrange and top end. in turn your compression lowers as the cylinder increases rpms and the valves open. a point in the compression scale is 15psi. when you said 90 you were referring to the psi. 90 psi is equal to about 6:1 compression. lets say compression say that a ratio of 5:1 means the motor is compressing 5 times the amount of air and fuel into the cylinder than normal pressure on earth.as our earth is 1:1 or 15 psi. 6:1 referrs to 6 times the normal pressure on earth. so when i say 7.2 to one you times that by 15 and you have psi. i approximated those numbers and they should be close or dead on. hope this helps. o by the way you may have to much blow by on your piston rings. this is why you have a low or to low of a number on your compression gauge. and/or your kips valves are open.

the trail rider · Jan 4, 2006

yes do what robl is saying if you have a 220 do your top end with a new wiseco piston kit about $115 bucks

Slowcarp · Jan 4, 2006

I'm not sure how much difference it will make but i have always been told the compression should be checked with the throttle held wide open. I would check the compression again, put in a new spark plug, do some wide open runs and check the plug color. As others have said it sounds too rich.

ridejunky · Jan 4, 2006

From what you described, it sounds as if your sub port exhaust valves(part of KIPS) may be stuck in the high rpm position, this can be caused by a rich carb and must be rectified. If you pull your
exhaust, and pull the cover from the left side of the cylinder that says KIPS, you can shine a flashlight in the exhaust port and you should be able to see the light in the reservoir of the cover you just removed. If you can't, you need to clean the KIPS. Read the article robl mentioned and look at the top end pictorial, this should help familiarize yourself with how it all works.

GS · Jan 5, 2006

Paul,
Step 1: put in a new plug
Step 2: ride it again
Question: did you use the choke to get it running and remember to then move the choke to the off position? You wouldn't be the first to forget that. I prefer to use the choke only as long as is absolutely necessary to keep it running.
Fuel / oil ratio OK? Reasonably fresh?
Compression may or may not be low, but it shouldn't miss just because of that.
Let us know how the plug works, OK?
Greg

gymrat86 · Jan 5, 2006

the trail rider said:
o by the way you may have to much blow by on your piston rings. this is why you have a low or to low of a number on your compression gauge. and/or your kips valves are open.

What do I need to do to get a higher compression. I just bought the bike used a week ago and it is a 2003 KDX 200. I want to know if I need to do a top end on it and if I should buy a new OEM carborater all together to avoid jetting. Please help.

gymrat86 · Jan 5, 2006

GS said:
Paul,
Step 1: put in a new plug
Step 2: ride it again
Question: did you use the choke to get it running and remember to then move the choke to the off position? You wouldn't be the first to forget that. I prefer to use the choke only as long as is absolutely necessary to keep it running.
Fuel / oil ratio OK? Reasonably fresh?
Compression may or may not be low, but it shouldn't miss just because of that.
Let us know how the plug works, OK?
Greg

Thanks for the advice. When I get home from work today I will try all of these. I am also going to take off the KIPS cover and check and she if it is clogged or dirty. If I take off the top cover do i need to buy a new gasket? If so where at. Also I do not want to do a top end now at all possible. I am 19 and starting college on monday. Please help me out.

lepper · Jan 5, 2006

2 strokes and jetting are a fact of life. Buying a new carb is not going to get you around that.

Besides.... $20 worth of brass beats a $300 carb anyway you look at it......

GS · Jan 5, 2006

You've bought a fine bike...not too expensive to maintain at all. You MUST get a service manual. Look on that bidding place on the net. It will save you lottsa money and worry. These bikes are pretty tough...if all the fluids are kept in good shape and serviceed properly. The 200 has no reported piston issues unless ity is simply worn right out or somehow abused

Green Hornet · Jan 5, 2006

the trail rider said:
kips is the kawasaki integrated power valve system. it keeps your valves closed before 6000 rpms, the closed valves keep the compression higher. in turn before the valves open you have more compression and more low end on the bike. at 6000 rpms the valves open and give you more midrange and top end. in turn your compression lowers as the cylinder increases rpms and the valves open. a point in the compression scale is 15psi. when you said 90 you were referring to the psi. 90 psi is equal to about 6:1 compression. lets say compression say that a ratio of 5:1 means the motor is compressing 5 times the amount of air and fuel into the cylinder than normal pressure on earth.as our earth is 1:1 or 15 psi. 6:1 referrs to 6 times the normal pressure on earth. so when i say 7.2 to one you times that by 15 and you have psi. i approximated those numbers and they should be close or dead on. hope this helps. o by the way you may have to much blow by on your piston rings. this is why you have a low or to low of a number on your compression gauge. and/or your kips valves are open.

:yeehaw:

robl · Jan 5, 2006

gymrat86 said:
...and if I should buy a new OEM carborater all together to avoid jetting. Please help.

Don't buy a new carb. I'd suggest you start with the simple / cheap stuff first before you dive into the expensive stuff that will probably not help you. You're just going to have to start trying things.

Let's look at what you originally described. You said it's low on power, feels like it's "missing" and has a bunch of goo on the plug. This means there is more fuel in the cylinder than the engine can burn and it's starting to foul the plug. You didn't leave the choke on, did you? Someone suggested replacing the plug, which will be a good starting point. (assuming the choke wasn't left on). But if you stop there it will foul again. You need to fix the source of the problem.

Possibility number 1 - your air filter is completely clogged. This will create a rich condition. Clean and re-oil your filter. You should do this anyway.

Possibility number 2 - your carb is jetted way too rich. You need to lean up your jetting. This is not hard. Really. Just get in and try it. If you want your 2 stroke to run properly, you must do this. 2 strokes are much more sensitive to altitude, humidity and temperature than 4 strokes and require different jetting for different times of year, parts of the country or altitudes. It's very easy. Just get in there and play with it.

Here are some hints that should get you started with jetting:
1. Remove the tank and seat so you can see things better.

2. Loosen the clamps on the engine and airbox side of the carb.

3. Rotate the carb in its boots so that the top is facing you.

4. Remove the metal cap on the top of the carb. (like taking the lid off a jar) and pull the slide assembly out.
a. There is a 6mm nut on top of the needle. You will need to remove it and disconnect the throtle cable to access the needle clip. Moving the clip higher will make it run leaner. You should only move it 1 position at a time.

4. Rotate the carb in the boots so that the bottom is facing you.

5. Remove the bottom cover (4 small screws)

6. The main jet is the larger one in the center. Once removed, the size is stamped on it.

7. The pilot jet is the smaller one to the side of the main. It also has its size stamped on it.

It's been my experience that adjusting the jets down 1 size, and moving the clip up 1 position will make the bike run quite a bit better. You might give that a try. The stock jetting is almost always too rich.

8. Replace the bottom cover, the slide, tighten things up and reinstall the tank and seat.

Go riding and see what happens.

robl · Jan 5, 2006

Here's another good read:
http://www.motocross.com/motoprof/moto/mcycle/carb101/carb101.html

gymrat86 · Jan 5, 2006

robl said:
Don't buy a new carb. I'd suggest you start with the simple / cheap stuff first before you dive into the expensive stuff that will probably not help you. You're just going to have to start trying things.

Let's look at what you originally described. You said it's low on power, feels like it's "missing" and has a bunch of goo on the plug. This means there is more fuel in the cylinder than the engine can burn and it's starting to foul the plug. You didn't leave the choke on, did you? Someone suggested replacing the plug, which will be a good starting point. (assuming the choke wasn't left on). But if you stop there it will foul again. You need to fix the source of the problem.

Possibility number 1 - your air filter is completely clogged. This will create a rich condition. Clean and re-oil your filter. You should do this anyway.

Possibility number 2 - your carb is jetted way too rich. You need to lean up your jetting. This is not hard. Really. Just get in and try it. If you want your 2 stroke to run properly, you must do this. 2 strokes are much more sensitive to altitude, humidity and temperature than 4 strokes and require different jetting for different times of year, parts of the country or altitudes. It's very easy. Just get in there and play with it.

Here are some hints that should get you started with jetting:
1. Remove the tank and seat so you can see things better.

2. Loosen the clamps on the engine and airbox side of the carb.

3. Rotate the carb in its boots so that the top is facing you.

4. Remove the metal cap on the top of the carb. (like taking the lid off a jar) and pull the slide assembly out.
a. There is a 6mm nut on top of the needle. You will need to remove it and disconnect the throtle cable to access the needle clip. Moving the clip higher will make it run leaner. You should only move it 1 position at a time.

4. Rotate the carb in the boots so that the bottom is facing you.

5. Remove the bottom cover (4 small screws)

6. The main jet is the larger one in the center. Once removed, the size is stamped on it.

7. The pilot jet is the smaller one to the side of the main. It also has its size stamped on it.

It's been my experience that adjusting the jets down 1 size, and moving the clip up 1 position will make the bike run quite a bit better. You might give that a try. The stock jetting is almost always too rich.

8. Replace the bottom cover, the slide, tighten things up and reinstall the tank and seat.

Go riding and see what happens.

Sounds simple but once i know the size of the main jet and the pilot jet where do i get another size at. Also today I noticed after I replaced the plug it still acted like it was missing and loss of power. but not as bad as before i replaced it. Also how do I clean out my stock silencer, what do i need to do to clean it. One more thing, if i take the head off the top end will i ruin the gasket, if so where can i get a new one. When i look at the piston how will i know if i need to replace it.

1swarty · Jan 5, 2006

Help

If you have only had it a week, change the gas, clean the carb and put fresh premix in it. Don't try to clean the plug, replace it! If you still have issues look further at that time!
Swarty

robl · Jan 6, 2006

You've cleaned and re-oiled the air filter, right?

You replaced the plug with a new one?

Have you got fresh pre-mix in the tank like 1swarty said?

Did you run it for at least 30 minutes? They will do that when cold, and can take 10 - 20 minutes to completely warm up.

Here's the thing though - With a brand new plug, it should still make power when you really rev it up even if you are running rich.

Once it’s up to operating temperature, turn the choke back on. Does it run even worse? If it doesn’t change anything, you have a carb issue.

You might check the fuel petcock (on / off valve) to make sure it isn't clogged. Pull the fuel line off the carb, point the line into a jar and turn on the fuel valve. It should flow like crazy. (gravity fed)

Next, you might have a problem with the silencer. I have heard of 1 case where an FMF pipe came apart inside and clogged. Made the bike run terrible.

On checking the jetting: Is there a competent Kawasaki dealership near by? If there's a good KDX guy in the service department, he should be able to give you a starting point on jetting for your bike and area. The parts department can tell you all the available jets for the carb and get them for you.

While you’re looking at the carb, you should thoroughly clean it. (all passageways, ect) I just squirted carb cleaner through everything and that did the trick.

If all of the above checks out, then you might look into the electronics. It could be a weak stator. I don't know much when it comes to these pieces.

If the fuel delivery system and electrical, and exhaust all check out fine, then you're doing a top end.

If you get here though, the good news is that you will have a very solid bike you can be confident in.

gymrat86 · Jan 6, 2006

Big Problem

You guys are such a big help. Here is what I have done so far. I have dismantled the carb and took out the main jet and pilot jet and will replaced it with a 155 main jet and 42 pilot jet and also moved the needle clip up one notch. I havent started the bike yet because im waiting for my jets to come in. Also I have ordered a brand new airfilter. What do I need to use to oil it up? Also I cleaned out my sparkarrestor and drained the spooge out of it. I also completly cleaned the carburater with carb cleaner and changed the gas. I am now using Havolines TC-W3 two stroke oil with a 40:1 mix of gas and oil. I also use 10w-40 motor oil in my transmission. I have heard that people use gear oil also such as Gear Saver 80W. Is that better to use than 10w-40? The only fear I have now is starting it cause last night I wanted to look at the piston and when I loosened the bolts "Just a bit" not much at all, coolant seeped out of it and im afraid that some of it might have got in my engine but I dougt it did cause as soon as I saw the seepage i torqued them back. Do i need to rechange the transmission oil. I have a bottle of gear saver 80w and didnt know if that was the right stuff to use. Is it ok to crank it up. Also my compression on my engine when I hooked the meter into the sparkplugg hole was 90 something. is that good? If not what do i need to do? thanks so much for your help, please let me know as soon as possible.
-Paul Graham
2003 Kawasaki KDX 200

Big Problem? Please help

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