Reviving a 93 KDX200

[sthoward]

Hi KDX'ers, I'm new on this forum and new to KDX's as well. I just picked up a non-running 93 KDX200 and I'm trying to get it to fire.

Previous owner said it had a top end done within the last year. It died one day, they got it running again after a lot of kicking, and then 5-10 minutes later it died again and they couldn't re-start it after that. It's been sitting about 4 months since then.

It has compression, and there is a spark although it's a little weak. Not sure if this is a problem or not.

I cleaned out the main and pilot jets. Anything else I need to check in the carb?

There is a small chip on the corner of one reed, would this be enough to stop it from running?

Any other suggestions?

[Keystone]

I have some stock 1993 KDX200 reeds in excellent shape (I'm using boysen). I don't think that's your problem, but if you want them message me your address and I'll shoot them out.

[bultaco4ever]

I doubt that little chip would cause hard starting. I too am restoring a '93. As for hard starting...mine has been reluctant to kick start also. Bump starting is not a problem. There are so many things to check that I'm just one by one, checking things that are common sense. Get yourself an owners manual. You'll be doing yourself a big favor.

Pop the head and cylinder off. Don't take the PO's word for it that the top end is new. Check the rings for wear. And piston clearance. Check the KIPS valves...a common failure point.

Make a note of what size your jets are, and your needle, and your needle clip position. Start adjusting carb settings and make notes if it improves or gets worse. I bought 'new' jets...a bunch of them different sizes for tuning. Manual will show how to set the float height...do it.

Try an Iridium spark plug....NGK BR9EIX

How's your air cleaner?

Mine is going back together this week after a KIPS valve replacement job and new reeds. My reeds looked worse than yours. I'll let you know if this all helped.

[bultaco4ever]

Dear all members....I need some help with terminology. Sthoward's photo shows the brass reed cage over the petals. My bike doesn't have that. What is it called and is it necessary? I don't see it in the parts availability schematic drawing. (sthoward...can you show a bigger photo of the entire reed block with the petals on?)

[sthoward]

Here are a couple more pictures.

[6 Riders]

Dear all members....I need some help with terminology. Sthoward's photo shows the brass reed cage over the petals. My bike doesn't have that. What is it called and is it necessary? I don't see it in the parts availability schematic drawing. (sthoward...can you show a bigger photo of the entire reed block with the petals on?)

Those are reed stops....Doesn't look like you can buy them separate. If you only have two pedals on each reed, then it's aftermarket. If not, you are probably looking at buying an AM reed cage.

[bultaco4ever]

Did all 'E' models come with reed stops?

[ohgood]

Hi KDX'ers, I'm new on this forum and new to KDX's as well. I just picked up a non-running 93 KDX200 and I'm trying to get it to fire.

Previous owner said it had a top end done within the last year. It died one day, they got it running again after a lot of kicking, and then 5-10 minted later it died again and they couldn't re-start it after that. It's been sitting about 4 months since then.

It has compression, and there is a spark although it's a little weak. Not sure if this is a problem or not.

I cleaned out the main and pilot jets. Anything else I need to check in the carb?

There is a small chip on the corner of one reed, would this be enough to stop it from running?

Any other suggestions?

I would check the stator (pull the cover, rotor, and inspect) and make sure the flywheel key is not sheared.

those reeds are fine, and would not prevent starting. mine started with one reed laying in the reed cage, but ran poorly.

I have a brand new set I tried to give away a while back that you're welcome to, just pay shipping or send me something cool from the first ride you have FUN on.

[ohgood]

also, if you don't have good airflow or of the silencer, it will never run. make sure there is no blockage from the air box all the way through to the arrestor.

spark should be FAT and BLUE anything else is unacceptable.

[sthoward]

also, if you don't have good airflow or of the silencer, it will never run. make sure there is no blockage from the air box all the way through to the arrestor.

spark should be FAT and BLUE anything else is unacceptable.

Thanks, great info. I wondered about the spark, she's BLUE but she sure ain't FAT!

Is this more likely caused by a bad stator? Or CDI?

[sthoward]

I would check the stator (pull the cover, rotor, and inspect) and make sure the flywheel key is not sheared.

those reeds are fine, and would not prevent starting. mine started with one reed laying in the reed cage, but ran poorly.

I have a brand new set I tried to give away a while back that you're welcome to, just pay shipping or send me something cool from the first ride you have FUN on.

Stator and woodruff key look good. Stator resistance is within tolerance. I can't seem to buzz out the CDI with my multimeter, I only get open circuit where the manual shows resistance ranges.

Cleaning the carb and air filter next.

[ohgood]

I would check the stator (pull the cover, rotor, and inspect) and make sure the flywheel key is not sheared.

those reeds are fine, and would not prevent starting. mine started with one reed laying in the reed cage, but ran poorly.

I have a brand new set I tried to give away a while back that you're welcome to, just pay shipping or send me something cool from the first ride you have FUN on.

Stator and woodruff key look good. Stator resistance is within tolerance. I can't seem to buzz out the CDI with my multimeter, I only get open circuit where the manual shows resistance ranges.

Cleaning the carb and air filter next.

remember the CDI being something i could not meter out myself. i don't recall if it's because it's not energized while checking, or what.. jaguar likely knows the answer. he's the guru of gurus.

you're getting a blue spark, so let's assume that is working fine since the key is not sheared.

don't dip the carb in cleaner, there is an o-ring seal under the jet block (the thing the jets screw into) that will be destroyed if you dip it, and you'll have to order that gasket from jetsrus before reliable running will happen.

how's the compression ?

[sthoward]

don't dip the carb in cleaner, there is an o-ring seal under the jet block (the thing the jets screw into) that will be destroyed if you dip it, and you'll have to order that gasket from jetsrus before reliable running will happen.

Thanks! I didn't know about the O-ring. I used a spray can of contact cleaner, which is supposed to be safe for plastics and such.

I noticed the air screw was only 1/2 turn out, with a 150 main and 48 pilot jet. (I'm at sea level). Should I put it back together the same way? I was thinking it should be at least 1 turn out.

how's the compression ?

150 PSI on my el cheapo compression tester.

[KDXrider1989]

also, if you don't have good airflow or of the silencer, it will never run. make sure there is no blockage from the air box all the way through to the arrestor.

spark should be FAT and BLUE anything else is unacceptable.

Thanks, great info. I wondered about the spark, she's BLUE but she sure ain't FAT!

Is this more likely caused by a bad stator? Or CDI?

check your contact points, where the coil bolts to the frame, the connectors on the coil, all should be free of rust and clean for good connection. another thing to consider, the spark plug boot literally screws onto the plug wire. over the years it couldve been rocked back and forth to the point of corrosion and being worn out... trim your plug wire about 0.5" and reinstall your boot, see if all this and getting a new plug helps

[KDXrider1989]

don't dip the carb in cleaner, there is an o-ring seal under the jet block (the thing the jets screw into) that will be destroyed if you dip it, and you'll have to order that gasket from jetsrus before reliable running will happen.

Thanks! I didn't know about the O-ring. I used a spray can of contact cleaner, which is supposed to be safe for plastics and such.

I noticed the air screw was only 1/2 turn out, with a 150 main and 48 pilot jet. (I'm at sea level). Should I put it back together the same way? I was thinking it should be at least 1 turn out.

how's the compression ?

150 PSI on my el cheapo compression tester.

sounds about right, Im at sea level as well, Ive got a full exhaust boyesen reed petals aftermarket air filter and the airbox snorkel removed, my pilot is a 48 main is 145 I think and screw is no more than a full turn out last I checked

[sthoward]

sounds about right, Im at sea level as well, Ive got a full exhaust boyesen reed petals aftermarket air filter and the airbox snorkel removed, my pilot is a 48 main is 145 I think and screw is no more than a full turn out last I checked

Thanks for the info. I pulled the air filter, it's a Twinair! Pretty clean too. I cleaned it anyway.

I've never rebuilt an old bike, but I've heard that the jets can degrade over time. Is this true?

Should I try it with the old jets, or just put new ones in?

Any other carb parts I should replace?

Thanks all for the help!

[ohgood]

sounds about right, Im at sea level as well, Ive got a full exhaust boyesen reed petals aftermarket air filter and the airbox snorkel removed, my pilot is a 48 main is 145 I think and screw is no more than a full turn out last I checked

Thanks for the info. I pulled the air filter, it's a Twinair! Pretty clean too. I cleaned it anyway.

I've never rebuilt an old bike, but I've heard that the jets can degrade over time. Is this true?

Should I try it with the old jets, or just put new ones in?

Any other carb parts I should replace?

Thanks all for the help!

old jets are old jets, you never know if they're the right size or not. as far as 'runs' vs 'wont run at all', it would take a hugely wrong jetting proposition to make that happen. like, no holes in them at all, or both the jets missing completely.

even then it would probably still start and run, just very badly.

your compression sounds good, the spark sounds good (you did say it was fat and blue right ?) and fuel delivery may be to blame. drag it up a hill, and then roll down with haste, pop it into second or third gear and dump the clutch. it should crackle to life with choke if the jetting is anywhere near right. i'm assuming the kick starter (operator error) isn't working properly, or you just haven't quite got the knack of THIS engine yet.

while you're brainstorming and checking every nut/connector, here's a funny story:
my bike is a 2 kick wonder, when it's cold. i've let friends ride it to get an idea of what an OLD bike feels like, and just how much fun the kdx power delivery is out on the trail. they didn't have pattern of how to kick it down the first 10-15 times, and i would literally walk up, kick it once and it fire to life. it's the same every time someone gets on it.

KICK KICK KICK KICK
throttttttttle
KICK KICK KICK
nothing.... grrrrr
then i kick it pawow and it's runnning. they look pissed at me and ride off, only to stall it on some creek crossing, hill, or small log....

KICK KICK KIII.
grrrrrr !!!
KICK KICK KICK KICK KICK KICK

me: "stop wearing out my kicker already and KICK it !"

them: kick kick ki... click click cliiiiick KICPAWooooW ! and it's running. it takes about 20 times before they get the knack for it. from then on, one kick and they're off, or a 2 mph push (literally, it starts that slow) and drop into 2nd gear for an easy start.

moral of the story, sometimes you just gotta learn the machines parameters of starting. a 1/8 of a turn of throttle AT THE RIGHT TIME (according to your jetting) might be key. or half a turn. or none.

give it a few more kicks.

:)

[bultaco4ever]

I don't have the knack on my bike yet. (Owned it two mos.) But I can't bump start it like a pro.

[sthoward]

the spark sounds good (you did say it was fat and blue right ?)

Reading back my post now, and I can see that I wasn't very clear. Yes there is a spark, but it's not very strong. But before I spend money replacing the ignition components, I want to eliminate as many other variables as possible.

fuel delivery may be to blame.

This is the area I'm concentrating on right now. I cleaned the carb and air filter, and I'll put them back together as soon as the hockey game is over. (I'm from Canada eh?)

I''m assuming the kick starter (operator error) isn't working properly, or you just haven't quite got the knack of THIS engine yet.

That could DEFINITELY be part of the problem - I've never owned or ridden a KDX before - although the previous owner must have figured it out...

I once owned a Husqvarna WR300 that also had a "trick" to starting it. The kickstarter was short and it was mounted very high, such that my know-it-all teenage sons just couldn't quite get the hang of it. They would kick it 10 or 12 times with no results, and then just lose their minds when I strolled over and started it first kick...

[Julien D]

Did all 'E' models come with reed stops?

Instead of the stop, is there a brass strip running along the top which screws to the cage? That would be correct for aftermarket boyesen reeds. They do not require use of the stock reed stop.