I am trying to get this '94 KDX250 up and running and I am debating putting a whole new exhaust on it. It has a FMF gold series fatty pipe and the stock silencer. The silencer is shot so I'm going to replace it, but the head pipe is not cracked or dented its just old. The bike appears to have been spewing oil for a while due to bad rings. Is the pipe still good?
Can I save this head pipe?
- Thread starter alltat2ed
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dirt bike dave
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- May 3, 2000
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Yeah, the stock jetting on the KDX250 is way too rich. The bike runs much better with a leaner pilot, leaner main, leaner (thicker) needle and more cutaway on the carb slide.
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I know about the jetting. I got the new main and pilot today. When I say spewing oil I mean there is about an 18 inch wide puddle after only running the bike for about 60 seconds. That's more than there would be from the stock bad jetting. Do think the pipe is still usable even tho there probably a ton of oil caked in there.
dirt bike dave
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- May 3, 2000
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The problem was likely caused by the previous owner and the stock jetting, IMO. Over time, the silencer could have gotten saturated with oil due to the extremely rich jetting. So what's spewing out could be what has accumulated over time. There are probably several ounces of oil accumulated in that boat anchor of a silencer.
BTW, the previous owner could have been mixing lots of oil, and using an oil that did not burn completely at the low rpm and temps he was using the bike. The stock plug is too cold, also. Other poor maintenance practices like over oiling the air filter could have made the bike run even richer.
Kawasaki really missed the mark on the jetting for that bike. Even worse than on the 200. On mine, I went down 3 sizes on the main, 3 on the pilot, put in a leaner needle and put in a slide with 1 mm more cutaway.
BTW, my KDX250 tank measured 3.6 gallons, as did my friend's. The manual says 3.3 gallons. A quart of oil per tank would be about 14:1. With proper jetting, even that much oil would not cause a puddle to appear behind the bike.
BTW, the previous owner could have been mixing lots of oil, and using an oil that did not burn completely at the low rpm and temps he was using the bike. The stock plug is too cold, also. Other poor maintenance practices like over oiling the air filter could have made the bike run even richer.
Kawasaki really missed the mark on the jetting for that bike. Even worse than on the 200. On mine, I went down 3 sizes on the main, 3 on the pilot, put in a leaner needle and put in a slide with 1 mm more cutaway.
BTW, my KDX250 tank measured 3.6 gallons, as did my friend's. The manual says 3.3 gallons. A quart of oil per tank would be about 14:1. With proper jetting, even that much oil would not cause a puddle to appear behind the bike.
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- #12
Haha guys, just 40:1 I'm sure of it. you make good about the silencer being saturated tho. I have a pro curcuit on order now. Should be here this week along with the rebuild kit. I have a 158 main jet and a 38 pilot to go in the carb before it goes back on. If I change the needle out to do you think I could get away with leaving the stock #5 slide in the carb? Oh ya, and what could I do to clean out this head pipe so I could save it? (almost forgot why I started this thread)
dirt bike dave
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- May 3, 2000
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Most people continue to use the #5 slide because a #6 is expensive. An alternative (what my friend did) is to scribe a line 1mm up from the bottom of your slide, and grind almost up to the line. The 158 and #38 are what I used and should make a big improvement. I'd save the slide change and needle change for later, and just run it with the 158 and 38 for awhile.
I've never had to clean the inside of a pipe, but the bike is probably pretty tolerant of buildup. FWIW, I crushed my stock pipe about 50 miles into a 320+ mile two day dual sport ride, and the bike continued to run OK for the rest of the run though it was done on power. I was surprised it would run at all as the pipe was severely restricted.
I've never had to clean the inside of a pipe, but the bike is probably pretty tolerant of buildup. FWIW, I crushed my stock pipe about 50 miles into a 320+ mile two day dual sport ride, and the bike continued to run OK for the rest of the run though it was done on power. I was surprised it would run at all as the pipe was severely restricted.
Call some automotive shops and see if they have a hot tank, and will be changing their fluid soon. It will trash their tank. Throw the pipe on a fire, I doubt it will melt?
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- #17
Thanks for all the input guys. I have some oven cleaner here so I'll try that first. I'm having a hell of a time getting these KIPS valves out to clean them. The retaining screw is frozen solid, can"t budge it. It's not reverse threaded is it? The manual doesn't say it is so I doubt it
