New here, first kdx

[Nighthawk016]

Hi everyone, new here and new to kdx's. Not new to dirt bikes or trail riding. I've spent a significant amount of time browsing the forum and working on the bike. So far I've caught my bike up on almost all of the long deferred maintenance. Is there anything I should be looking out for on the bike? Right now im working on jetting because the bike is blowing a lot of oil at the spot where the silencer joins the expansion pipe. Hopefully I'll learn a lot more from additional browsing and searches.

[KDXGarage]

Welcome to kdxrider.net. Thank you for joining.

Which model (and year) KDX do you have?

If you select perfect jetting, there will still be a touch of oil in the pipe that may make it look less than perfect until it is all blown out. You might want to clean out the pipe before you get real close on perfect jetting to not trick yourself a little. Also, clean the spark arrestor / silencer.

[SS109]

Welcome to the KDX family!

[Chuck78]

Welcome! What year and model KDX do you have? Where do you ride? Do you have any photo album links for your bike?

[billie_morini]

Hello, Nighthawk016. What region are you located in?

[Nighthawk016]

Welcome to kdxrider.net. Thank you for joining.

Which model (and year) KDX do you have?

If you select perfect jetting, there will still be a touch of oil in the pipe that may make it look less than perfect until it is all blown out. You might want to clean out the pipe before you get real close on perfect jetting to not trick yourself a little. Also, clean the spark arrestor / silencer.

All super helpful advice thank you! I have a 2000 kdx220. I went out for a shake down ride this weekend, did 30 miles, didn't foul a plug, im still blowing out oil from the connection point of the expansion chamber and silncer.

[Nighthawk016]

Welcome! What year and model KDX do you have? Where do you ride? Do you have any photo album links for your bike?

No albums yet, I have videos to edit from my ride this weekend. I typically ride in lower peninsula in Michigan. Here are a couple pics

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[Nighthawk016]

Hello, Nighthawk016. What region are you located in?

Midwest specifically northern indiana

[billie_morini]

Hello, Nighthawk016. What region are you located in?

Midwest specifically northern indiana

Nighthawk106, I bet there's really nice forest riding there.

[Nighthawk016]

Hello, Nighthawk016. What region are you located in?

Midwest specifically northern indiana

Nighthawk106, I bet there's really nice forest riding there.

Oh yeah, unfortunately I have very little riding anywhere else, so my experiences are limited, but yes the trail are really good.

[KDXGarage]

"...still blowing out oil from the connection point of the expansion chamber and silncer."


Can you post a pic of the joint? It should seal well there.

[Nighthawk016]

"...still blowing out oil from the connection point of the expansion chamber and silncer."


Can you post a pic of the joint? It should seal well there.

Here are a few pics, this is after about 60 miles of riding, i cleaned the swing arm between the 2 rides

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[Chuck78]

That's quite a lot of oil coming out of that exhaust coupler... I'd say you may need to #1 replace that exhaust coupling, & #2 pull the drain bolt plug on the spark arrestor bottom rear, and see how much oil is sitting inside it that drains out (make sure the hole isn't plugged with carbon buildup preventing excess oil from draining out), and possibly remove your spark arrester silencer and flush it out with solvent to clear some excess residual oil and carbon.
#3 perhaps replace the carburetor's jet block gasket with a genuine Keihin piece from JDJetting.com (PWK33/35 Long Body carb). This requires a tamper proof torx security bit to get at, abd this part is NOT on any OEM parts diagrams from any manufacturer using Keihin PWK carbs, FYI.
This leaking any tiny amount of air can foul up your jetting and state of tune in general until replaced, and no amount of rejetting will fix it.

[Nighthawk016]

That's quite a lot of oil coming out of that exhaust coupler... I'd say you may need to #1 replace that exhaust coupling, & #2 pull the drain bolt plug on the spark arrestor bottom rear, and see how much oil is sitting inside it that drains out (make sure the hole isn't plugged with carbon buildup preventing excess oil from draining out), and possibly remove your spark arrester silencer and flush it out with solvent to clear some excess residual oil and carbon.
#3 perhaps replace the carburetor's jet block gasket with a genuine Keihin piece from JDJetting.com (PWK33/35 Long Body carb). This requires a tamper proof torx security bit to get at, abd this part is NOT on any OEM parts diagrams from any manufacturer using Keihin PWK carbs, FYI.
This leaking any tiny amount of air can foul up your jetting and state of tune in general until replaced, and no amount of rejetting will fix it.

Jet block is already done, made sure I got that out of the way early. Previous owner was running 50:1 mix with the needle on the 4th clip position, stock main and pilot. Im running 32:1, with the clip in the 2nd position, cleaned it up significantly. I found both of the mounts for the expansion chamber are ripped. So that probably has something to do with it. So ill be ordering a new coupler, and new mounts for the expansion chamber. I'll have to look at the drain to see if anything comes out. I suspect something will.

[Chuck78]

I just now noticed that you have a KDX220.

Do you know the maintenance history of it?

Most of the OEM 220 pistons, including the old stock that Kawasaki still will sell you, are garbage pistons that should not be trusted WHATSOEVER. Most were made by ART Pistons, who didn't know how to make a 2-stroke piston worth a darn, vs a very small percentage were made by SK Pistons, who successfully made a great 1986-2006 KDX200 piston... No clue why Kawasaki outsourced the majority of the KDX220 pistons to ART Pistons instead of SK Pistons, but it's a shame as they are well known to split apart in use and destroy expensive parts of your engine.

Hopefully yours has been replaced by a Wiseco or Wossner (easy to identify with the exhaust and spark plug/fuel tank removed, looking down the hole for a Wiseco part number etched into the crown or looking at the piston skirt machining (the forged pistons look a little bit different) and the telltale anti-friction coating on the Wossner piston skirts.

If this has not been checked, I highly recommend not riding the bike any further until you've verified if it has an aftermarket forged piston in it. If it has the good OEM piston (very rare), there's no way to easily tell until you pull the whole top end and look for the ART logo or the tiny maple leaf looking logo with SK in the middle (it's hard to make out, but the ART logo is very obvious).
Even an SK piston in a 220 after 20-28 years is probably due for changing out by now, but the forged Wiseco and Wossner generally last a lot longer than a cast piston as long as you make sure to ALWAYS warm them up gradually before ever reving the engine or doing hard acceleration or high RPM. The forged pistons need to see a minimum of 130 degrees coolant temperature before really getting on it hard. Cast pistons deal better with cold running, but forged ultimately are stronger and better in most other ways. Wossner is my choice over Wiseco despite Wiseco being made here in my home state of Ohio, and Wossner in Germany, Just make sure it is sized correctly. Wiseco only offers 1 size per bore, 69,00mm brand new no wear in cylinder sizing, and 70.00mm "225" big bore (223.2cc). If the cylinder has any wear on it, a Wossner B or C size will make it last far longer and with better compression than the Wiseco, Wossner offers 3 sizes for the stock 69mm bore, 69.00 A, 69.01mm B, and 69.02mm C-sizes. It's important to have the cylinder professionally measured with a dial bore gauge or telescoping bore gauges and calipers.

[Nighthawk016]

I just now noticed that you have a KDX220.

Do you know the maintenance history of it?

Most of the OEM 220 pistons, including the old stock that Kawasaki still will sell you, are garbage pistons that should not be trusted WHATSOEVER. Most were made by ART Pistons, who didn't know how to make a 2-stroke piston worth a darn, vs a very small percentage were made by SK Pistons, who successfully made a great 1986-2006 KDX200 piston... No clue why Kawasaki outsourced the majority of the KDX220 pistons to ART Pistons instead of SK Pistons, but it's a shame as they are well known to split apart in use and destroy expensive parts of your engine.

Hopefully yours has been replaced by a Wiseco or Wossner (easy to identify with the exhaust and spark plug/fuel tank removed, looking down the hole for a Wiseco part number etched into the crown or looking at the piston skirt machining (the forged pistons look a little bit different) and the telltale anti-friction coating on the Wossner piston skirts.

If this has not been checked, I highly recommend not riding the bike any further until you've verified if it has an aftermarket forged piston in it. If it has the good OEM piston (very rare), there's no way to easily tell until you pull the whole top end and look for the ART logo or the tiny maple leaf looking logo with SK in the middle (it's hard to make out, but the ART logo is very obvious).
Even an SK piston in a 220 after 20-28 years is probably due for changing out by now, but the forged Wiseco and Wossner generally last a lot longer than a cast piston as long as you make sure to ALWAYS warm them up gradually before ever reving the engine or doing hard acceleration or high RPM. The forged pistons need to see a minimum of 130 degrees coolant temperature before really getting on it hard. Cast pistons deal better with cold running, but forged ultimately are stronger and better in most other ways. Wossner is my choice over Wiseco despite Wiseco being made here in my home state of Ohio, and Wossner in Germany, Just make sure it is sized correctly. Wiseco only offers 1 size per bore, 69,00mm brand new no wear in cylinder sizing, and 70.00mm "225" big bore (223.2cc). If the cylinder has any wear on it, a Wossner B or C size will make it last far longer and with better compression than the Wiseco, Wossner offers 3 sizes for the stock 69mm bore, 69.00 A, 69.01mm B, and 69.02mm C-sizes. It's important to have the cylinder professionally measured with a dial bore gauge or telescoping bore gauges and calipers.

Honestly, I have no idea what the maintenance history is on the bike other than the guy I bought it from poorly maintained it. Based on what I've seen so far, using an educated guess, the original owner that had it 00-09 took fairly good car of it, but I cant say how many hours that owner put on it. The guy I bought it from just rode it, and lightly washed it, then repeated that. He claimed he put less than 50hrs total from 09-25 on the bike, which I find hard to believe, but I suppose it is possible based on the 2018 orv sticker the bike had on the rear fender.

Based on what you're saying it sounds like wossner uses the black tephlon coating on the skirts and im familiar with wiseco pistons. I'll need to get my shop all setup and warmed up to pull it apart and take a look.

As for replacing parts, ill have to see what my budget allows for. What I do know is the engine makes good compression, is easy to start hot and cold. I am assuming nothing is completely worn out. I would not be surprised to see the oem piston in the bike still, when I tore apart my rm250 I was the first one to split the cases, it still had oem seals gaskets and bearings.