93 KDX250- CANT START IT

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romanm
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93 KDX250- CANT START IT

Post by romanm »

OK, SO I CANT START MY BIKE.
I ALSO HAVE NO IDEA HOW TO PROPERLY TUNE THE CARB.

LITTLE INFO

- BIKE HAS A FMF GOLD SERIES PIPE.
- TANK FILTERS WERE CLEANED
- CARB WAS CLEANED
- MAIN JET IS A 160, DONT KNOW WHAT THE PILOT JET IS...MOST LIKLY STOCK
- NEW PLUG, YES IT FIRES (WHAT SHOULD THE GAP BE THOUGH?)
- AIR FILTER CLEANED AND RE-OILED
- NEW 30WT OIL IN THE GEARBOX
-COMPRESSION IS 90 ON THE FIRST KICK AND 110-120 ON THE SECOND AND THIRD

CAN ANYONE HELP ME TO GET IT RUNNING? IVE GOTTEN IT RUNNING AFER KICKING IT OVER GOT KNOWS HOW MANY TIMES, BUT I WOULD LIKE SOMETHING THAT FIRES UP WITHIN THREE KICKS AT MAX.

HOW DO I PROPERLY ADJUST THIS THING SO IT FIRES UP? BIKE HAS ME ANGRY AND WANTING TO SELL IT
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Julien D
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Post by Julien D »

First, welcome to the forum!

Second, easy on the caps. That goes for YELLING on a forum, and nobody likes being yelled at.

Third, this is in the wrong section.

Fourth, get an accurate compression reading. No matter what it is on the first, second, or third. Hold the throttle open and kick until the gauge stops rising.

At any rate, it sounds as if compression might be ok. I'd still like to see that accurate reading though. Are you using the choke to start it? Pull the carb off, remove the bowl, and clean everything. Pay extra special attention to the pilot jet!
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scheckaet
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Post by scheckaet »

start here for jetting:
http://www.kdxrider.net/forums/viewtopic.php?t=1156

find out what you pilot is. while you're in the carb make sure to clean all the circuit, sometimes they are gummed up and it can be really tricky to clean them.
For the jets, compressed air might not be enough and you might need something like a guitar string to clean them up...or get new ones.
Oh and caps are not necessary we get you :wink:
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Post by romanm »

sorry for the caps.......i work in autocad and am required to type in caps.

Ah...you know I didnt have it at WOT when i did the compression test....so it should only get better.

The carb is clean. I had someone with an ultra sonic parts cleaner clean it for me in the fall. For extra measure i re-cleaned it with brake cleaner this spring.

That article you posted....while the read is good and informative....alot of it requires to be able to have the bike started already, which I am unable to do. Im going to take apart the carb again and see where my needle clip is, and what my other jet is.

Does anyone know more or less how this carb should be set up so i can atleast get it fired up easily? From there Im sure I can tune it out
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Post by rbates9 »

Turn the gas on. :lol:
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Post by scheckaet »

when you try to fire it up, have you looked at your plug after kicking it a dozen times? Is it wet or dry?
if it's dry might be too lean of a jet?
float height set within limits?
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Post by plotski »

I have a 93 KDX250...had some issues with it starting at one point...turned out to be a combination of shot reeds and a partially plugged pilot jet. How can you have "no idea" what your pilot jet is if you had it out to properly clean it? Compression on this bike according to Kawaswki should be a Minumum of 140 and a max of 220 PSI. 90 to 120 is definitely on the "below specs" side of that. Just sayin. :supz:
Wherever you go......there you are

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1997 KDX220 Street Legal !!
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Julien D
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Post by Julien D »

^ he's right.

Get us that compression reading, please. My guess is it will be in usable range, but that's just a guess. If the compression is good, we can move on to looking at possible causes.
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Post by romanm »

Ok, so the motor gave me highest compression reading of 130. The motor could definitely use a new gasket set and a new set of rings, but I don't have the time or money right now.

I pulled the reed block out after, but it looks like its sealing fine. no gaps on the tips of the reeds.

I also now have the carb out, and am in the process of cleaning it again. Ill use the string method to clean out the pilot and main jet. Ill also inspect the needle and see what position the clip is in. Can anyone give me a pointer as to where it should be?

main jet is 160....i also have a 165 on hand
pilot jet is a 42

I have spark, and when i pulled the plug, it was wet.

$#@&....I just wanna go out and ride!!! the weather is soooo beautiful!
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Post by scheckaet »

Your plug is wet so you are getting fuel in, it's just not igniting. Maybe you get too much fuel?
also what is your elevation?
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Post by nearma12 »

Change the spark plug. Even if it sparks when you pull it out and check, it doesn't mean that it is sparking under compression.

If the plug is wet, it may be fouled. The same thing has happened to me before.

The jetting is probably still a little rich. I ran 38/152 in my KDX250. Not sure what altitude you are at, but you could probably go down to 40/155 and clean it up a lot.

Also, adjust your airscrew on the carb. It is the small slotted screw on the rear left side of the carb. You should probably start by turning it all the way in then turn it out to around 1 1/2 turns as a starting point. Then fine tune it (In = richer) (Out = leaner) until it runs the best.

I bet that a new plug and a quick tune of the carb will fix most of your problem. The lower compression will probably make it hard to start though anyway.
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romanm
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Post by romanm »

my altitude is 200m. I live in Ontario, GTA area.

I just spent the last hour adjusting the fuel level.....I have it .5-1mm below the top portion of the bottom bowl....or the bottom of the top portion of the carb. Im hoping this is correct as that is how I understood it form the manual. I used a cork and some tube to figure it out using the hole at the bottom.

Cleaned the pilot and main jet out with brake cleaner, and compressed air.

The slide is a number 5

the needle is r1368H...second clip from the top

Im gonna put it all back together and hopefully the sl*t fires up.
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Post by romanm »

Im also a little confused with the air-adjust screw (located on the bottom) and the idle adjuster (located on the top)

Is the air adjust screw the one I back out 1.5 turns as my starting point?
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Post by scheckaet »

yup. but it's only to get started on jetting your bike. once you have the proper size pilot, it's used to fine tune throttle response depending on altitude, temperature, humidity...
it's better explained in the jetting section.
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Post by SS109 »

Just throwing this out there but it could be a weak spark issue. Double check that all wiring is corrosion free and that all ground connections are clean and tight.
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Post by stomlinson »

I agree drop to a 40 pilot, and probibly 155 or maybe even 153 main 160 seems huge
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Post by stomlinson »

Also get a new plug go to a br8 slighly hotter than the br9, and try going to a good high quality 2 stroke oil!!! I run MC1 made by belray at 50:1 with high test and my bike runs clean with that fuel
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Post by ChubbyWookie »

Try putting all Jets,carb adjustments etc... back to OEM (of course after cleaning it thoroughly) don't forget to set proper float height. Make sure exhaust system is free of any debris and flows freely. Check Ignition timing on Magneto/flywheel. Test output voltage of sparkplug (should be between 40-65KV)
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Post by SS109 »

>|<>QBB<
stomlinson wrote:I agree drop to a 40 pilot, and probibly 155 or maybe even 153 main 160 seems huge
I'm running a 38 pilot/158 main, #5 slide (I think it has been modified to #6 specs), 1369N needle, clip in the middle, BR9 plug, 32:1 Maxima 927, and I get no spooge, no plug fouling, and it runs great at 2000'-2500' elevation.

So, I don't see the 160 main being a problem at his elevation (200m = 656ft) or even the 42 pilot. Even before I switched needles from a 1368H like his, which made my bike spooge like crazy, it still started and ran good with no plug fouling.

It seems you have tried most of the solutions with the carb so I would start exploring the electrical side of things. Replace the plug, check your plug wire to make sure it is good, and double check all connections making sure they are tight and clean. It might not be a bad idea to test the source and the ignition coils. A weak spark coupled with the low compression could very well be the problem.
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Post by romanm »

Well, The bike was working for about 200km. Turns out the float level was set up wrong by myself earlier. Also, The bike was fouling plugs like crazy. Every ride (avg40km) I had to replace the plug

But once again, she quit working. Put in a new plug and she isn't starting. This bike has really been getting on my nerves.

Does anyone here have a step by step or how to on rebuilding the engine? I think Im going to start there......all new gaskets and a new top end so Im not getting any leaking gaskets or anything, and so i have solid compression so tuning the carb wont be wonky. Im not gonna bother touching the bottom end because I don't have the money/skill for that...unless it absolutely needs to be done.

This nikasil plating though has me wondering though if the rebuild is going to be harder now or easier. Guess I wont know till I crack her open. But with my understanding, The bore should not change since the coating is so hard right?
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