KDXRIDER.NET

okay ladies and gentlemen, I have a question about my 1991 kdx200. I have cleaned the carburetor out and it runs great, it idles great, and I couldn't be any happier. When I shut the engine off however, the drain tube from the fuel bowl leaks gas all over the ground unless you shut the fuel petcock off. When the engine is running there is no fuel out of any of the drain hoses. Is this something normal that I am experiencing? That the bowl would drain when the engine is off? is this a sign of a stuck float? The engine runs so nice and crisp though.

Check the float valve rubber tip and closing area.

Re cleaned and still have the same issue. It is the drain hose and not the vent hose just to be clear.

As I recall the drain is the bolt on the bottom of the bowl. The hose coming out from near the bottom of the bowl is vented to the top of the bowl. If you're overflowing it's probably your float valve.

This happens to me too on an H-series. I just set the float height and cleaned everything and it leaks from the drain tube. Jeff Fredette said the carb can be tilted in the boot, leading to this, but mine is perfectly set in the notches. Looking forward to a remedy for this.

I have the same issue on a 2005 I just bought my son. Took the carb off, cleaned all the internals (including rubber tip) yet still have a leak. It is not constant - more of a burble every 1-2 minutes or so. Unfortunately I did not have the presence of mind to check my float height while everything was apart. So I will check that, but if that does not work then I am guessing the rubber tip has hardened over time so I will replace it with a new one and see what that does.

I had the same problem a couple of years ago. I replaced the floats and the float valve and adjusted it. Solved the problem.

Did you find a solution? I'm going to tear my carb apart soon to see what is causing this.

I have order new floats, needle and gaskets. Parts here by tomorrow and plan to install an ride Thursday. Pretty certain it will fix the issue. There just isn't much more to it and if day the 8yr old rubber bits have gone a bit hard!


Sent from my iPhone using Tapatalk

Float valves can drive you crazy sometimes. You can usually tell if the rubber (viton) is worn because it will have a "shoulder" where it rests in the seat. Other than that they are pretty durable. Usually the problem is contamination of some sort in the bucket. You can't see it but it is there. 90% of the time it can be fixed by putting some polishing compound (or toothpaste) on a q-tip and "polishing" not only the seat but the entire bucket. Then clean the carb and reassemble. The 10% of the time that this doesn't work is when it can drive you to drink. In all my years riding motorcycles I would say that float valves have coused me the most frustration. They look so simple but they can be a cruel mistress.

You can help prevent future problems with proper use of your petcock. When I get close to the truck I like to reach down and turn my petcock off so I can run some fuel out of the bowl before I park it. That way the float valve is in an open position instead of the floats pushing it against the seat. For long term parking (more than a day) I turn the petcock off and let the bike run until it dies. That way, if a day turns into a week and a week turns into a few months, I won't have varnished fuel in the bowl.

Great advice/tips and yes it's maddening! My rmz450 is fuel injected so for now anyways my problems are limited to just the one bike.


Sent from my iPhone using Tapatalk

was having the same problems, tried to adjust the float according to the service manual with no luck (i needed one more hand!). anyway, check out this video (a couple of bad words if you're offended or have kids near by). i set mine up this way, and no more fuel dumping on the ground!!



hope this helps

That's a great trick! Beats the heck out of putting the carb on and off or using and auxiliary tank and getting gas everywhere.


Sent from my iPhone using Tapatalk

The solution I found is to shut the gas off when the bike is on the kick stand. It only leaks when the bike is angled on the stand. The float height must be right on the ragged edge.

I have an update on this. I took the carb off, removed the bowl, and used a Q-Tip on the hole that the float needle sits in. I then blew through the fuel line inlet. At first, no air was coming out of the float needle hole, but then a sudden burst of air shot out. Maybe it was clogged with something? I then set the float height properly, as before when I did this, the little tang was bent too far down, depressing the needle bumper and giving me a false float height reading. I raised the tang, set the floats to 16mm, bent the tang back down a little, and buttoned it back up. I tested it out by filling a bowl with water, setting the carb in up to the expected fuel level, and blowing on the fuel inlet. No bubbles whatsoever! I tossed the carb back on the bike, turned the petcock on, and observed no leak. I ran the bike, shut it off, left the fuel on, and it was dry as a piece of matzo bread. YEE HAW! And I didn't even have to buy parts.

Good that you got it all fixed.