Keihin Carburetor Flooding... newb please help!!!

Discussion specific to the 1995 - 2006 KDX200 (H Series) and 1995 - 2005 KDX220R (A Series) models sold in the USA
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clarkn!gga
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Keihin Carburetor Flooding... newb please help!!!

Post by clarkn!gga »

So I got a 95 KDX200 as my second dirtbike (first was a yamaha RT100 fyi). It was running pretty rough when I got it but I got it for a steal so no worries. At first the bike had no top end power when I test drove it so I figured I could clean the carb and have a badass dirtbike for cheap. So I cleaned the carb out thoroughly (disassembled it) and when I put it back together had even worse problems. Now the bike is still hard to start but once it goes start up it idles decently but within almost 30 seconds of revving it up the bike bogs, stalls and floods. I know it is the carb flooding because when the problem occurs I look down at the carb to find it is wet with gas coming from the overflow valve. A few times after countless kicks and a very sore right leg I got it to start again with the fuel flow shut off (thats how I determined it was getting too much gas). But it either dies when the fuel in the lines runs out or when I turn the fuel on and rev it the flooding happens again. Anyone have any ideas? I am new to this so any advice is greatly appreciated.
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rbates9
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Keihin Carburetor Flooding... newb please help!!!

Post by rbates9 »

When you cleaned the carb did you soak it in a carb cleaner or just spray it out. If you soaked the carb then you will need a new jet block gasket. If you just sprayed out the carb did you remove the jets to clean them and the carb passages? It sounds like the float is stuck so you need to start there. Pull the carb back off and check the float height and float needle.
clarkn!gga
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Keihin Carburetor Flooding... newb please help!!!

Post by clarkn!gga »

When i cleaned the carb i just kinda sprayed out the carb itself and let the jets sit in a bowl and soak. Also I adjusted the float height to the service manual specs (16mm) and put the throttle needle C clamp at the most lean position. It backfired a few times after kicking the hell out of it but did not want to start. I then proceeded to jump start down a hill still no luck. Then I tried various positions of the idle screw choke on choke off then resorting to the previous throttle needle position, pretty much everything and still no luck. Even with the float height adjusted it still leaked a little gas out of the carburetor but not as bad as before.my thoughts now are fresh plug, drain the gas tank, clean it and start with premium good fuel with some seafoam in it.
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rbates9
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Keihin Carburetor Flooding... newb please help!!!

Post by rbates9 »

If it leaks a little gas while it is leaning on the kick stand that can be normal. If it is still leaking when the bike is straight up then you have a float issue of either wrong height or bad seat / needle. Make sure you can see thru the jets and all the holes are clear. Also spray some cleaner thru the jet passages and make sure it comes out some where.
clarkn!gga
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Re: Keihin Carburetor Flooding... newb please help!!!

Post by clarkn!gga »

Okay thanks for the advice! Is it possible that the difficult starting could be signs of needing a new top end? I don't know anything about the bike so I am hoping for the best and preparing for the worst.
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bufftester
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Re: Keihin Carburetor Flooding... newb please help!!!

Post by bufftester »

You probably should pull the carb and double check everything/respray like RBates said. Pay special attention to the needle valve and the seat, make sure the Vitrol tip (black rubber part) is in good shape and no damage to where it seats in the carb body. While you have the carb off just take a look at your reed valves as well. Definitely dump the fuel and mix a new batch along with a new plug. Take a read through this thread http://kdxrider.net/forums/viewtopic.php?f=105&t=1156 to get an idea of the tuning process. I'd start with the needle in the stock position. Wouldn't hurt to go through your wire harness and just make sure all the bullet connectors are clean and secure, ground connections free of corrosion, no visible cracks in the high tension lead. If you have the tools a compression check wouldn't be a bad idea either...may not be just a carb issue but several things working together so try and rule out as much as possible.
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rbates9
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Keihin Carburetor Flooding... newb please help!!!

Post by rbates9 »

Like he said.

I think you need to get your fuel flow issue sorted out before you get too carried away.

A compression check would be a good thing to do but will not help with a overflowing carb. A lot of auto parts stores will rent or loan a compression tester to you if you don't have one. Or you can pick up a tester for cheap. A good, no, the best investment for you to make will be a repair manual if you don't already have one. :wink:
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bufftester
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Re: Keihin Carburetor Flooding... newb please help!!!

Post by bufftester »

2nd on the manual...won't get far without one.
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