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Good to hear!

fooled again..... I got my kdx out again this weekend. Fired up great... Ran good for about 15-20. Then started running like not so good then off...... Plug fouled. Plug was new but had a ton of build up on it when I pulled it. Not wet like usual more like carbon build up. P!ug might of had 20mins total on it.

To date i have only got 15-20 mind of ride time on each attempt... Super frustrated. It's like the bike finally gets warm and Running optimal then blaap! Dead in the trail.

What am I missing?

You said earlier that you were running the B8ES plug, why? Kawasaki specs that it should be the BR8ES and felt the need for it. Doubt that is the problem but I have seen stranger things. The "R" part of the part number stands for "resistor" which suppresses the electromagnetic interference from the ignition system from harming or interfering with electronics. The CDI's on our bikes are electronic so it is something I would correct just to eliminate even the remote possibility it could be an issue. Speaking of ignition, even though it looks like you have good spark, it could be weaker once the coil warms up causing the plug to not reach optimal temperature and fouling out.

I would seriously consider doing a leak down test to eliminate the bottom end from being a part of the problem. It also might be worth double checking the reeds. Service limit for them is .2mm or .01". If they are of unknown hours, and even if in spec, I would replace them just as another way to eliminate them as the issue.

Anything else has to be carb related but, like I said above, I have seen some strange things so good luck!

SS109 wrote:You said earlier that you were running the B8ES plug, why? Kawasaki specs that it should be the BR8ES and felt the need for it. Doubt that is the problem but I have seen stranger things. The "R" part of the part number stands for "resistor" which suppresses the electromagnetic interference from the ignition system from harming or interfering with electronics. The CDI's on our bikes are electronic so it is something I would correct just to eliminate even the remote possibility it could be an issue. Speaking of ignition, even though it looks like you have good spark, it could be weaker once the coil warms up causing the plug to not reach optimal temperature and fouling out.

I would seriously consider doing a leak down test to eliminate the bottom end from being a part of the problem. It also might be worth double checking the reeds. Service limit for them is .2mm or .01". If they are of unknown hours, and even if in spec, I would replace them just as another way to eliminate them as the issue.

Anything else has to be carb related but, like I said above, I have seen some strange things so good luck!

Just ordered the correct plugs. I going to look into new reeds also. Got to do some research on here to see what everyone likes. Leak down test as soon as I can find someone to do one that isn’t going to charge an arm and a leg.

Thanks


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Got my reeds on the way also. I don’t know why I have been ordering those plugs. I ordered them wrong the first time and have just kept getting the same from amazon. I bet I have been through 4 boxes!!!
Now that I think about it.... when I bought the bike it was on the super rich side. Tons of spooge but never fouled the plug. When I started the jetting guide I replaced with a new plug and it all went down hill from there... I will swap reeds cause I don’t know how old they are. Correct plug and I still am going to do a leak down test at some point.


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Do you have a Service Manual for your bike?

Really, this is the most important tool you can have for your KDX. It answers soooo many questions and saves so much time and aggravation. This is the most frequently posted recommendation here on this site.

pumpguy wrote:Do you have a Service Manual for your bike?

Really, this is the most important tool you can have for your KDX. It answers soooo many questions and saves so much time and aggravation. This is the most frequently posted recommendation here on this site.

Didn’t come with a manual. I haven’t looked for one either. I imagine they are readily available.


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near the top of the home page...

http://www.kdxrider.net/forums/

I was digging around last night in the shop and found the plug that was originally in the bike. It was a BR4ES.

Not sure how relevant that is.

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That's pretty bad.

A BR4ES is WAY hot for these motors, an 8 is recommended, a 9 if you have any work done to increase compression is usually good.

Slight update..... put new reeds in tonight. I am pretty sure the old ones came from the factory. When I bought the bike I looked at the reeds and they seemed good but after I got them off the cage they had a barely noticeable bend. Being new to 2t I simply didn’t see anything obvious so assumed they were good. Replaced with Boysen 607. Put a fresh BR8ES in. Fired her up in the shop. Throttle off idle is night and day. No more slight bog. I let it run probably 20-30 mins. I would walk over and rev it out occasionally. Even after many mins at idle it was crisp off idle. Then slight bog mid but would clear up and scream. Even after running at pretty much idle for the majority of the 30 mins it didn’t foul the plug. I am optimistic.

Now..... I am hoping to maybe get out and ride tomorrow that should be the test. If I can get out and ride an hour with no issues I will be elated! Still plan on doing a leak down at some point just for peace of mind.

Now.... if I have been getting my butt kicked the whole time over a spark plug and set of reeds I am a bit embarrassed. On the other hand..... I learned something.

Thanks again for all the help and encouragement. I will update as soon a possible.


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VERY GOOD news!

If I may suggest it, unless you are in a cold environment, allowing the bike to idle for 30 minutes in not too great for engine temperature.

wouldn't e the first time plugs and reeds got a 2T rider!

Awesome! I hope that has finally solved the problem.

Sounds like good news. I saw you mention that you're wanting to do a leak down test. You can make a tester for less than you'd pay someone to test the engine. Here's a link to one I made and then a couple pictures using brass which I like a lot better than the pvc fittings. If I had to do it over again I would get the 0-15 psi gauge, air bulb, and expansion plug from Amazon and then head to the hardware store for the rest. It would somewhere between $30-$50 to build one of these two depending on where you shop.

http://www.kdxrider.net/forums/viewtopi ... 89&t=21554

Got out for a quick ride.... new reeds definitely helped with performance. 15-20 min of riding and a moderate pace..... fouled plug. I didn’t even pull it to look at it. I just pushed it in the shop and walked away.




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Now that you have new reeds, it may be time to test and adjust the jetting. I have fouled a plug much more quickly than that in my time, so don't give up now. With new reeds, you have eliminated one variable.

Gotta be something with the carb...In 15 years of owning the same KDX I have fouled.........wait for it.....ZERO plugs. I have replaced them a few times, not really sure why. 40:1 Motul for the last few years and I've had OEM, RB'd, and Lectron carbs. Never a fouled plug. BR8ES the entire time.

Side note - I've owned a lot of 2T through the years and fouled plugs at inopportune times more than once. I'm still amazed that it's never happened on the KDX. I always carry spares, but have yet to need one.

Hang in there, you'll get it back in shape. Lots of knowledgeable minds here. Well...there may be a few exceptions...

Ok, now it's down to the carb or a leaking right crank seal. I'm betting on the carb.