Need help -KDX not running??

Mountainman650 · Post by **Mountainman650** » 08:23 pm Jun 27 2005

Hey guys (93 KDX 250)
I was riding Sunday, about 90 degrees, dusty, rode for about 2-3 hours,
some tight single track and some WOT dirt roads.
Was riding back to the truck to meet up with my riding buddy and she just sputtered and died... First response- go to reserve, started in 2-3 kicks, rode about 100 feet and she died again, seems like no fuel.
Checked tank -got around 1/3 tank give or take?? No pressure build up in tank ,so the vent hose seems unclogged. pulled plug , not really fouled, but tried another, no go. Called buddy on cell phone and had him meet me at the nearest township road , gotta love cell phones...Pushed bike to the road ( did I mention 90 deg. temps,man that sucked) loaded up and homebound.
First thought was dirt in fuel , maybe clogged the jets,? Tonight I pulled the carb apart seemed like the main had some dirt in it ,ah ha, just to be safe drained the tank ,put in fresh gas., put carb back together.
STILL NO GO

...... Any thoughts are more than welcome......
Also I just installed a new Moose air filter, so that should be good to go.
I haven't checked spark yet , hard to do with one person

, any thoughts??

Please help
Thanks
Dave

skipro3 · Post by **skipro3** » 08:40 pm Jun 27 2005

Check the spark by pulling the plug. That way you can turn over the motor by hand and watch the plug spark away.

I bet you have a bad plug. A bit of carbon shorting things out or some such. Even if the old plug sparks, sometimes they won't under compression or after a bit warmed up. I had one do that in a generator once. Use a brand new plug.

Tickle the carb by tipping the bike over so you know fuel is being routed the right way through the carb and seeing it come out the overflow tube(s).

Let us know what you find.

m0rie · Post by **m0rie** » 11:05 pm Jun 27 2005

Make sure your carb overflow tubes are not clogged.

quailchaser · Post by **quailchaser** » 12:43 am Jun 28 2005

If the spark is good.

One other place to check is the pet cock filter screen inside the tank. Pull the pet cock and make sure the screens are clean. I've had this be the cause for an "out of fuel symptom" on other machines.

Good luck and keep us posted on your findings.

Later
Robb

canyncarvr · Post by **canyncarvr** » 11:21 am Jun 28 2005

Something you might not have noticed or been ABLE to notice when you had the carb apart was a sticky float needle.

If you don't find some other obvious culprit (like the vent tubes and petcock already noted), replace the float needle and while doing that, clean the needle seat (strip of 400 wet-n-dry ..used wet 'natch.. over a cotton swab. Spin it 'round the seat with slight pressure. Clean it up with a strip of 600.)

Check your carb floats. If tweaked, they can hang up on the bowl. More likely vents, petcock or float needle/seat.

When the bike has quit, it may be useful to take the plug out of the bottom of the bowl. Should be full of fuel. But...just the wiggling around during the plug removal may seep enough fuel to make it seem OK when it's not.

Hope you don't have sparky-box problems! Excitor coils can get finicky when they get hot.

All of the above stuff has been known to be a problem with one rider or another. If you don't find a fuel problem give RickyStator a call...he would likely know if your make/model/year is prone to pickup coil failures.

Mountainman650 · Post by **Mountainman650** » 09:01 pm Jun 28 2005

Hey guys
Thanks for all the replies, I had a long day at work today ,so I didn't get a chance to pick up a fresh plug today. I did check for spark though ,and it does have spark . I know the "overflow ports" on the side of the carb are open from when I took the carb off yesterday, but I'll have to check out the tubing to see if it's clogged. The screen inside the tank should be ok?, I get good fuel flowing from the hose , on both ON/Reserve.....
I'll keep you guys posted
Thanks
Dave

canyncarvr · Post by **canyncarvr** » 01:00 pm Jun 29 2005

Note: good fuel flowing from the hose does NOT take a sticking float valve into account.

If the float needle has ANY marks on the tip, replace it. I'm assuming it is a Viton tip. If it's brass, just clean it using the same stuff you clean the seat with.

Let us know the good news!

Mountainman650 · Post by **Mountainman650** » 07:49 pm Jun 29 2005

Thank you all
The problem was the plug!!!!
I installed a brand new spark plug and 1 kick and she fired right up!!!!!

I had 2 older plugs that came with the bike and none of those worked at all?....
weird how something so simple can ruin your day. I bought 2 new plugs just to be safe...

Actually this has not been all that bad , because now I know what jets are in the carb.
165 main
42 pilot?
clip on Needle on 3rd groove from top(or bottom since there's only 5, lol)
I'm actually running a bit rich now, so I may go to a bit lower main ..??
Moving the clip up the needle will lean a bit ,? correct??

Thanks again
Dave

I

m0rie · Post by **m0rie** » 08:00 pm Jun 29 2005

The 165 main is why your plug fouled. You can start with a 155 and work down from there.

-Maurice

TD3 · Post by **TD3** » 06:04 am Jun 30 2005

My brother-in-law just picked up a 92 KDX250 last week with FMF Fatty and Silencer. It was last used for ice-racing and was still jetted rich. To clean it up a bit with what I had on hand, we went with a 158main, 42 pilot, AS @ 2.5 out, needle clip #4. This setup work pretty well (but smoked a lot) and it didn't foul the plug on some very slow technical trails. We have ordered a 38 pilot and I think that will put it in the ballpark.

Good Luck!

canyncarvr · Post by **canyncarvr** » 03:04 pm Jun 30 2005

m0rie: It's a 250..with..'uh..some kinda 38mm PWK (I think Jason said).

I point that out only 'cuz I would have likely missed it (just happened not to this time...so I'm patting myself on the back).

re: 'pulled plug , not really fouled, but tried another, no go.'

????? I read that, then read what Ski said (I bet you have a bad plug)...and wondered why he said that. I figgered he just missed the 'tried another', but didn't make a big deal out of it.

I did wonder about 'another' as opposed to 'a new' plug.

Was the 'another' a used plug? Several reasons why not to do that..and they all boil down to, 'Don't do that!'

Note: The hotter the ambient air, the richer you run...air/fuel wise.

Moving the clip 'up' does lower the needle, does result in a leaner mixture in the range of effect OF the needle.

#1 slot is the first slot from the blunt end. Some needles have six positions..so #3 isn't always in the middle. That important jewel of non-essential information noted for absolutely no reason whatsoever.

m0rie · Post by **m0rie** » 03:25 pm Jun 30 2005

canyncarvr wrote:m0rie: It's a 250..with..'uh..some kinda 38mm PWK (I think Jason said).

Yeah I did miss it. Doh! Another assumption bites the dust!

I still think a 158 or 160 is going to be closer to correct on the main than the 165 though. Might as well put those extra plugs to work and do a couple of plug chops and set the main.

I don't think PWK's use needles that have 6 slots. I think thats only for the 4t FCR's?

-Maurice

canyncarvr · Post by **canyncarvr** » 04:24 pm Jun 30 2005

Didn't say which..just that 'some' have six.

Thought it might oome in handy when he's jettting somebody's CRF250 over the phone......

Post by **KDXGarage** » 05:37 pm Jun 30 2005

I am glad to hear you got it going again! A new plug is better than a "new to you" or "different" plug.

A quick check of the http://www.buykawasaki.com site shows stock jetting on a 1993 KDX250 to be 42 pilot, #5 throttle valve, R1368H needle and 165 main jet.

The best way to know what is in your bike is to check yourself instead of relying on what someone else, some website or a spec chart says. Congratulations on getting this important first step out of the way.

If you think the jetting is off, try one change at a time and keep everything written down.

The highest groove is the #1 groove ( by the blunt end like canyncarvr said), with #5 being the bottom groove (assuming it is the stock needle). If you do some jetting research, you may see some KDX200 riders mention buying a Keihin part number needle instead of an OEM needle to save money. I think there is no Keihin direct equivalent for that needle, as it would be a CJH and the sudco site doesn't show one. The closest Keihin needle is two clip positions shorter (CGH). Running that needle in clip #1 would be like running your needle in clip #3.

As far as Keihin part number replcacements, I think all the KDX220R stock needles are the same way about Keihin part number replacement availability.

I hope this helps. Again, good job on replacing the plug with a new plug! Throw those old plugs in the garbage ASAP!

By the way, yes stock carb was a PWK38.

Mountainman650 · Post by **Mountainman650** » 07:51 pm Jun 30 2005

Hey guys
My set-up must be stock yet, because everything Jason
quoted was my exact set-up, even the R1368H needle.
I'll have to do some experimenting one step at a time....

And now I know never use a used plug.....
I aprecciate all the advise , I haven't really messed with two-smokes in years.
Thanks again.
Dave

skipro3 · Post by **skipro3** » 07:59 pm Jun 30 2005

canyncarvr wrote:
re: 'pulled plug , not really fouled, but tried another, no go.'

????? I read that, then read what Ski said (I bet you have a bad plug)...and wondered why he said that. I figgered he just missed the 'tried another', but didn't make a big deal out of it.

I did wonder about 'another' as opposed to 'a new' plug.

Yup! I figured when he said another plug, that it was a used plug. Usually folks will state that they used a brand new plug. They make a point of pointing that out. Then I look to see if they gapped it. Most guys risk damaging the plug trying to gap them with something other than the correct tool. Or else they just dropped the plug in the bike after it's been dropped somewheres else and it has no gap at all.

skipro3 · Post by **skipro3** » 08:04 pm Jun 30 2005

While I'm at it, let me just say, I'm amazed at how the plug gap can affect performance; especially starting the bike.

My plug, a fancy smancy iridium was over gapped and that bike always took 3 or more kicks to start. Even harder when warm.
I checked the gap one day, thinking no way it had changed and was it ever off! Regapped and that bike starts so easy now.

Just thought I would remind folks to check that gap ever 500 miles or so. (2-3 months for me)

canyncarvr · Post by **canyncarvr** » 10:43 am Jul 01 2005

Gee...I'll have to check my plug a couple of times just this weekend!

KDXer · Post by **KDXer** » 01:00 pm Jul 01 2005

BRADLEY !!! Didn't your momma ever tell ya "It isn't nice to gloat"

Hmmm ?? No !! Well she should have !!

1000 miles indeed

Better pack a spare piston, rings, w/pin bearing, lower shock bearing, r/tyre, etc

Aside of all the jealously I hope you have a fantastic time and return safely.

skipro3 · Post by **skipro3** » 11:13 pm Jul 01 2005

CC, ditto on the have fun this weekend. I'm going to start a thread so everyone can post what their plans are for the holiday weekend and how it all worked out.

Trev: American holiday on Monday: 4th of July; Independance Day. Google that if you don't know what that is.

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Need help -KDX not running??

Need help -KDX not running??