First Issue with my Ex Team Green KX500

[2-Stroke Tom]

My buddy and I went out riding last weekend in the desert, and when we first got out the we rode about 30 miles, and then we stopped to take a break for a while. My bike ran flawless, and we decided to go for another run. My bike started first kick, and I pulled away from camp and it felt like a spark plug was starting to foul (never happened to me on this bike before, but I had a high performance KX125 back in the days before high tech plugs, and it would foul plugs if it wasn't warmed up properly) so I pulled it in neutral to figure out what was happening, and it wouldn't rev above 1/4 throttle. I opened my gas tank, and I could see my IMS gas cap seal (less than one years old) disintegrated and was sitting on the petcock screen. I thought I had found the problem, but this wasn't it. It would run better with the choke on, so I new there was a fuel supply problem. Got around to cleaning the fuel tank out yesterday, and from the flow coming out of the petcock before I cleaned it, I new a clogged petcock screen wasn't my problem. Took off the throttle from the carb and found this in the first picture.

For those of you who don't know, I bought this Ex Team Green bike a few years ago and haven't done anything but basic maintenance and ride the hell out of it since I bought it. I did a leakdown test on it when I first got it, and it seemed very tight. Watching all of these builds and various project on kxriders, and being an engineer/ex mechanic, it was hard not to pull the bike apart to check everything out and freshen it up. I just couldn't bring myself to disabling the bike for a while because it runs so good, and it has never missed a beat. After I found the broken needle jet, I went ahead and pulled the reeds out for the first time. They look brand new, but I will replace them for piece of mind. The piston looks pretty good, although there appears to be some cracked intake bridges. I will send it to Kaw Rider when I do the rebuild in the next six months or so. Take a look.

I also thought some of you would like to see how Team Green modded their radiators for the desert. Completed welded up, thread boss welded in with spacers to get the radiator shrouds positioned to grab the max airflow over the radiators.

[kxpegger]

Piston looks good!

[Motorrad]

Is the bleeder on the left rad welded up like it is on my 91 team bike?

[Polar-Bus]

Wow, never heard of a carb needle breaking at the C clip groove ! What an extremly odd issue. Good diagnostic work to quickly find the problem !

[2-Stroke Tom]

The needle actually broke below the c clip groove, and I can't figure out why this happened. The slide doesn't appear to be worn out, and it fits snugly in the carb bore.

Motorrad, you are correct, the left side radiator has the bleed screw welded up. Same thing with the bleed screw on type of my cylinder head, Team Green must have had some coolant leak issues, so they welded the entire system up. Just have to be careful when doing a coolant change so you don't trap air.

[Motorrad]

The needle actually broke below the c clip groove, and I can't figure out why this happened. The slide doesn't appear to be worn out, and it fits snugly in the carb bore.

Motorrad, you are correct, the left side radiator has the bleed screw welded up. Same thing with the bleed screw on type of my cylinder head, Team Green must have had some coolant leak issues, so they welded the entire system up. Just have to be careful when doing a coolant change so you don't trap air.

Yep... My Original head had the bleeder welded up also (Now hangs on the wall)..

[2-Stroke Tom]

I tried to order the same replacement needle, which was a N82P from cheapcycleparts.com. Just got an email that this part is backordered, so I ordered the stock needle (N82M) in the meantime. Anyone know where to find a N82P needle?

I'm sure Team Green jetted the bike properly, since it always fires first kick when it's warmed up, throttle response is crisp, and with my 40:1 fuel mixture the silencer seems to have the perfect amount of oily wetness at the end after a full days ride. I haven't even checked the jetting with spark plug readings because it's got to be pretty close if it runs this way. That's why I will try and get the N82P to throw back in it.

[snoopjonnyjon]

Those intake bridges may or may not be cracked. There's a parting line there on every casting. Sometimes it can be extremely difficult to tell what is actually cracked, and what is just a casting flaw.