2000 kx 80 questions

[tbaer]

i just bought a 2000 kx80 for my wife to ride. the bike has the usual stuff wrong with it, clutch needed adjusted, bars were bent, plastics beat up, grips ripped, but this thing starts first kick hot or cold!!! I have 3 questions

1. the bike smokes alot and bogs off the start but cleans up and runs great on the top end. what could be the issue here? carb tuning or power valve issue?

2. I went to take the plastics off and the radiator shroud wont come off of the tank. is there a special way to get this off? it feels lik ethe insert is spinning.

3. I can find black plastics, but where can i find a black tank? IMS wants 280 for a tank which is outragous!!!! I might just get all the plastics covered in line-x then i wont have to find a tank. well my question is will a 2001 kx85 tank fit my 2000 kx80?

[mustangfury]

I may be able to help with question number 1. I have a kx125 but it had smoking issues and if you look at the topic in kx125/250 http://www.kxriders.com/forums/index.php/topic,7313.0.html it may help.  I had it to where i was getting oil spitting out the back of the silencer and getting all over the rear fender and stuff. the carb was jetted too rich. i also had a problem like your first question where it would bog up to about 3/4 throttle and then drag me down the road like there is no tomorrow. 

IMO it sounds like a carb problem/ jetting.

If you are lacking only mid range power it could be either a pilot jet problem or you might need to just change the jet needle clip position.  I had this problem as well and whoever had the bike before me was running it on the leanest setting. The bike was craving fuel. I moved the clip richer to the stock setting and what a difference. it just goes the same all through the gears. 

To check and see if you need more or less fuel. Try accelerating through the range where it bogs then try it with the choke on. If it does better with the choke on you are running lean and the bike needs more fuel. if it does worse or even stalls with the choke on you are running rich and the bike is getting too much fuel.

In jetting the carb you want to start with getting the right main jet and then tweak with the others from there to work on the lower speeds.  You set the main jet by focusing on the engine performance at 3/4 to full throttle then work down from there. You can tell a lot about how your jetting by simply looking at the spark plug.

Also make sure the bike is up to temp before judging anything.

what does your spark plug look like after riding and letting it cool down. Oil deposits? what color is the electrode? - brown, white, black?  etc.  What throttle ranges specifically does it bog at (i.e. 1/2 to 3/4)

Different jets control different ranges.
here is a reference for which jets control which ranges of the powerband.
http://www.keihin-us.com/am/_media/pdf/slide_valve.pdf

here is a diagram of a pwk keihin carb. i'm assuming that is what your bike has
http://www.keihin-us.com/am/_media/pdf/pwk_parts.pdf

The more info you give us the better we can assist you. 

[cbxracer30]

You may want to check the opening on the head end of the exhaust it maybe all gummed up and in need of a cleaning, also the silencer maybe gummed up also. Clean,clean,clean the airbox out - the rubber connecting boot - also the fuel tank empty out the old fuel make sure the screen is clean and yes the carb ,yamaha carb cleaner works great.

[mustangfury]

I would have to agree w/cbx.  Before you go changing any jetting, you should make sure it isn't just a minor clogged air filter or gummed up carb or silencer like cbx said.  I also use gumout or brake cleaner (doesn't leave any residue) for the carb.  i would start there if you haven't done so already.

[tbaer]

filter is brand new uni. i will clean the pipe and silencer and see if that helps before i rip apart the carb.

i still need help on a new tank. will a 2001 kx85 tank fit a 2000 kx80?

[mustangfury]

let us know what you find.

Good luck!

[07 450 cam]

I may be able to help with question number 1. I have a kx125 but it had smoking issues and if you look at the topic in kx125/250 http://www.kxriders.com/forums/index.php/topic,7313.0.html it may help.  I had it to where i was getting oil spitting out the back of the silencer and getting all over the rear fender and stuff. the carb was jetted too rich. i also had a problem like your first question where it would bog up to about 3/4 throttle and then drag me down the road like there is no tomorrow. 

IMO it sounds like a carb problem/ jetting.

If you are lacking only mid range power it could be either a pilot jet problem or you might need to just change the jet needle clip position.  I had this problem as well and whoever had the bike before me was running it on the leanest setting. The bike was craving fuel. I moved the clip richer to the stock setting and what a difference. it just goes the same all through the gears. 

To check and see if you need more or less fuel. Try accelerating through the range where it bogs then try it with the choke on. If it does better with the choke on you are running lean and the bike needs more fuel. if it does worse or even stalls with the choke on you are running rich and the bike is getting too much fuel.

In jetting the carb you want to start with getting the right main jet and then tweak with the others from there to work on the lower speeds.  You set the main jet by focusing on the engine performance at 3/4 to full throttle then work down from there. You can tell a lot about how your jetting by simply looking at the spark plug.

Also make sure the bike is up to temp before judging anything.

what does your spark plug look like after riding and letting it cool down. Oil deposits? what color is the electrode? - brown, white, black?  etc.  What throttle ranges specifically does it bog at (i.e. 1/2 to 3/4)

Different jets control different ranges.
here is a reference for which jets control which ranges of the powerband.
http://www.keihin-us.com/am/_media/pdf/slide_valve.pdf

here is a diagram of a pwk keihin carb. i'm assuming that is what your bike has
http://www.keihin-us.com/am/_media/pdf/pwk_parts.pdf

The more info you give us the better we can assist you. 

haha wish i read this when my  kx 80 was running spat oil everywere (back fender aswell) would go average then just shoot off like a rocket haha oh well not to worry 450's are alot funner still got the 80 hope to restore it one day