98 kdx 200 foulin plugs every hour of riding

krash and burn · Feb 26, 2008

I just bought a 98 kdx 200 last summer. It has ran great. This year however, it is fowling a plug about once an hour, so i have to load my tool bag up with a dozen plugs to go riding. we did just repack the muffler(it was nasty). My riding shirt is ruined from crap spraying out the muffler. I am running 50-1.
The guy who sold me the bike said it will not run great unless you run 50-1. Another thing is im only getting about 30 miles on a tank of fuel. Can anyone tell me the problem. The bike is completely stock except for fatty pipe and muffler.

ridejunky · Feb 26, 2008

Do a search on jetting, stock is way too rich. Whats your clip position? Are you using too cold of a plug? whats your altitude etc?

krash and burn · Feb 26, 2008

Im running a stock plug (Br8es). Im staying below 10,000 feet riding the foothills of washington state. I tell ya, after a good hour of riding, my plug fouls, i pull it out and it is pitch black soaking wet , throw a new one in and off i go to do it again in another hour. My idle screw/air screw does nothing when you turn it clockwise or counterclockwise, so i dont think that is working either.

bmcd308 · Feb 26, 2008

You're rich

50 to 1 ratio - more gas per unit of liquid, so richer mixture than what Kawi recommends

altitude approaching 10K feet - higher altitudes mean less oxygen per unit of volume of air, which richens your mixture.

When your bike was running better, were you running it at sea level?

As asked above, tell us what jets and clip position are in there. There is some chance that the previous owner left the stock jets in and found it to be spooging oil because it was running rich. Kawi jets them pretty rich from the factory.

Because bike is rich, the PO tells you to run 50 to 1, thinking that less oil in the gas will solve the spooge problem, but that actually makes it worse. You thank him and take the bike home from sea level, and now it fouls plugs. No surprise. It was rich at sea level, and then the 50 to 1 mix caused it to get richer, and then the altitude makes it richer still.

If the air screw does not do anything, then you know you have a carb problem of some sort - most likely jetting that is not even close.

Just an idea.

krash and burn · Feb 26, 2008

excellent info, ya learn something new everyday. I will find out jet sizes(i assume they are stock) and post it tomorrow..........thanks

ridejunky · Feb 26, 2008

bmcd308 said:
50 to 1 ratio - more gas per unit of liquid, so richer mixture than what Kawi recommends

altitude approaching 10K feet - higher altitudes mean less oxygen per unit of volume of air, which richens your mixture.

When your bike was running better, were you running it at sea level?

As asked above, tell us what jets and clip position are in there. There is some chance that the previous owner left the stock jets in and found it to be spooging oil because it was running rich. Kawi jets them pretty rich from the factory.

Because bike is rich, the PO tells you to run 50 to 1, thinking that less oil in the gas will solve the spooge problem, but that actually makes it worse. You thank him and take the bike home from sea level, and now it fouls plugs. No surprise. It was rich at sea level, and then the 50 to 1 mix caused it to get richer, and then the altitude makes it richer still.

If the air screw does not do anything, then you know you have a carb problem of some sort - most likely jetting that is not even close.

Just an idea.

Just an Idea? You couldn't have put it better, great answer.

98 kdx 200 foulin plugs every hour of riding

krash and burn

ridejunky

krash and burn

bmcd308

krash and burn

ridejunky

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