Kx250

[duke barwick]

i ve been reading this for a while now and no one mentioned your airscrew position, 40 to 1 is richer than 32 to one so your problem may get worse. also next time you pull your plug cap look inside the cap and see if any dirt residue. this area gets overlooked frequently and is a big problem area. set your airscrew at 1 and half turns out. then open it 1/8 of a turn at a time til it runs best. if you go over 2 turns out then you have the wrong jets in your scooter. change pilot jet til you bike runs best with your airscrew back to 1.5. this is your ideal setting assuming you are running the same gas/oil mixture . good luck, duke

 

[Guest]

I would like to thank every for there help, but I believe i'm my own nightmare. I went through another plug today so I came home and pulled my stock original silencer today. It was like petrified wood. I remember someone telling me that could cause it. I replaced it and and the bike ran great. I think I'll kep an eye on it. I'm such an idiot.

 

[Dave Riley]

Mark,

If you have tried rejetting with your silencer packed up you may have gone too far in either direction (rich or lean).  Rich won't hurt but too lean will trash your engine.  Keep an eye on your plug to make sure it doesn't look completely white.  If you haven't changed your jetting you should be OK.

 

[duke barwick]

while i have some kawasaki nuts on line, my friend has a 1999 kx 125 , he tells me that his airscrew only turns out about 2 turns. is that normal.? no he doesnt have the book on it

 

[Guest]

The book says to turn it two turns, but don't know if it's the max turns. 03 kx125.

Does anyone know the reasoning behind the fouling of the plugs with a dirty, nasty, silencer. My neighbor doesn't seem to be convinced that was it?

 

[Dave Riley]

IMHO, it is caused by the gas not being evacuated from the cylinder completly which causes the incoming charge not to be completly burned.  On a 2 stroke the shape, length and constriction (same as shape) all combine to both help the burned gases exit and to pull the new charge in.

From Eric Gore's web site:

2.Now the transfer ports are uncovered at about 120 degrees after TDC. The scavenging phase has begun. Meaning that the unburned mixture gasses are flowing out of the transfers and merging together to form a loop. The gasses travel up the backside of the cylinder and loops around in the cylinder head to scavenge out the burnt mixture gasses from the previous power stroke. It is critical that the burnt gasses are scavenged from the combustion chamber, to make room for as much unburned gasses as possible. That is the key to making more power in a two-stroke engine. The more unburned gasses you can squeeze into the combustion chamber, the more the engine will produce. Now the loop of unburned mixture gasses have traveled into the exhaust pipe's header section. Most of the gasses aren't lost because a compression pressure wave has reflected from the baffle cone of the exhaust pipe, to pack the unburned gasses back into the cylinder before the piston closes off the exhaust port.

Aftermarket Silencers

Silencers come in all sorts of shapes and sizes. The idea is to use the silencer to maximize the pressure and velocity in the pipe. That profile will be different for powerbands and riders' demands. Too much pressure in the pipe at high rpm will radically increase the temperature of the piston crown and could cause the piston to seize in the cylinder. Designing the silencer is the final step when developing a pipe package.

Silencers are designed on the dyno and verified on the racetrack. Generally speaking if you buy an aftermarket pipe, buy the silencer to go along with it. Some popular silencers have optional end caps that have spark arrestors built into them.

All that being said, it just seems to help a bunch with power and plugs not to mention that a properly packed silencer is a lot quieter.

 

[Guest]

if my clutch cable wasn't adjusted correctly, would that might have something to do with it, just got done cleaning and adjusting it and it seems to be snapping back like when it was new?

 

[Guest]

It has nothing to do with the road at crooms.
You must work out the jetting.
WOT will work ,but make the jetting change...:??

 

[Guest]

i mix my bikes at 40:1, but when my dad mixes them, i think he does it at 44:1. I use Champion WP2 water pumper. I have been using that stuff for at least 3 years, and i have never fouled a plug.

 

[Guest]

Mark:

What year is the KX250?  I'm running stock Pilot, Stock Needle in 2nd clip position (stock), Main Jet lowered from 160 stock to 158.

You may be over-oiling your air filter.  This would explain having too much oil everywhere, including inside your silencer.  Filter oil won't burn like 2-cycle oil.

I'm running 32:1 Yamalube.  At 50:1 I'd bet money on Yamalube you'd blow the motor.  Only look at numbers like 50:1 with synthetic oils like Bel-Ray H1R.

I got the 2001 from Orlando Yam-Kaw Leftover.  They are great people.  Also, what plug are you running?  Do you keep putting in the Platinum plug that is stock on that bike, or are you using a regular BR8ES?  Have you tried different heat ranges of your plug?

Finally, are you washing your bike before you start it at home? You may be getting water past the airbox boot and possibly into the carb, which could easily foul a plug trying to start an engine w/ very little fuel and a lot of water.

Feel free to contact me anytime and I'll go over it w/ you.  This problem has nothing to do w/ your clutch, or the road you ride out on.  Do you ever get into the higher revs?  Do you let your bike cool at Croom, then start it again?  Once the bike is cool, do you foul plugs?

What brand air filter oil are you using?  I'm sure I can get this solved for you.

Brian

 

[Guest]

When I took the silencer apart it was like a petrified log, haven't had the problem since. Starts every time and keeps on running. Stayed at 32:1.