I took my 81 KDX around the block to get some fresh fuel into the carb , then turned off the gas as I often do to gently run it until it dies. It started to sputter, pulled into the garage then WAAAAA! went lean and stayed at max revs for about 30 sec, kill button did nothing. It eventually died and didn't sound like it seized, kick starter moves the piston fine. Should I worry or check anything? I was messing with the idle screw and had it turned in pretty far, trying to tune out a bog but having the screw so far in is probably what caused the issue. Kind of scary, I couldn't kill it and just held both brakes full tight until it died, I was picturing it clicking into gear and launching into the garage wall.... :yikes:
DAINGIT!! Did I hurt my bike?
- Thread starter Bark3rd
- Start date
I was doing the same thing with my bike today and noticed as it got close to using all the fuel it started to rev as well. I just mashed the brakes and popped it into gear and killed it.
I am not really sure why it did it. This bike as well as 2 strokes are new to me. was it smoking a little more then normal?
I am not really sure why it did it. This bike as well as 2 strokes are new to me. was it smoking a little more then normal?
dirt bike dave
Sponsoring Member
- May 3, 2000
- 5,349
- 3
When the bike leans out and heats up from the lack of lubrication, the tip of the spark plug will get superheated enough to fire the fuel even without spark. That's why the kill button does not work.
Since the bike is in neutral and not under load, it does not take much fuel and air to make it rev, even though the throttle is closed.
Even though the motor is revving high, it's not making much power because it's not getting enough fuel or air to make serious power.
It's certainly not good for the motor, but there was probably no damage done.
IMO, it's not worth tearing it down to inspect, unless the motor shows signs of weakness next time you ride.
From now on, if you want to get gas out of the float bowl, just use the drain plug. ;)
Since the bike is in neutral and not under load, it does not take much fuel and air to make it rev, even though the throttle is closed.
Even though the motor is revving high, it's not making much power because it's not getting enough fuel or air to make serious power.
It's certainly not good for the motor, but there was probably no damage done.
IMO, it's not worth tearing it down to inspect, unless the motor shows signs of weakness next time you ride.
From now on, if you want to get gas out of the float bowl, just use the drain plug. ;)
- Thread starter
- #5
HA ha, thanks. Over the years I can remember this happening a few times with other bikes but I was never in the garage and I was able to kill by putting into gear. It was frustrating, I was stuck and just waiting for it to seize. The KDX has a bog I cant seem to get rid of, it comes into the powerband, then stutters, then goes 'clack CLACK" like its missing. Ive played with the jetting a bit but am wondering if this is a reed or top end issue. It starts and idles fine, running with choke on and off doesn't help. Any ideas?
In come tacks
Member
- Feb 10, 2010
- 37
- 0
Running out of gas or hard downshifting can cause seizure. I've had the "running out of gas" seizure happen, but it usually doesn't. It seems more likely to seize if you're riding the bike when it goes that lean. But anytime you overheat, you can lose control of the spark, so like Dave says, the plug thing is the way to empty the bowl.
I've never understood the idea of running the bike out of gas that way.
Unless you don't plan on riding it for a good long while, it won't hurt to leave the gas in the carb.
If your riding it every week, it should be just fine.
Then there's that whole drain plus issue. Almost every single carb uses a 17mm plug. It's really not hard to remove.
If that's too much work, just turn off the petcock, and lay the bike on it's side for a while.. It'll drain out that way.
Unless you don't plan on riding it for a good long while, it won't hurt to leave the gas in the carb.
If your riding it every week, it should be just fine.
Then there's that whole drain plus issue. Almost every single carb uses a 17mm plug. It's really not hard to remove.
If that's too much work, just turn off the petcock, and lay the bike on it's side for a while.. It'll drain out that way.
Intentionally leaning out your bike, to the point of autoignition? What a nasty habit to get into! Stop it! There are a lot safer methods of draining the fuel completely from your bike. You should run ether oxygenated race fuel, it needs to be drained from the plastic tank after every ride. DANG IT, in the kdx forum, again, oh well. Yes, leaning the engine in such a manner, can lead to catastrophic failure, very easily. Personally, draining the fuel does not leave you exempt from crud growing in your carb. If you are using alcohol oxygenated fuel, you are allowing a drying period inside the carb, and this type of fuel is very good for carrying moisture with it. Buy some seafoam and be done with it all, for periods of not riding. Otherwise, stop over thinking it, it will be fine for a day or 2 for sure! Keep it simple. KDX or not, they still require periodic maintenance, and there are no short cuts. Vintage Bob
Dirtdame
Member
- Apr 10, 2010
- 146
- 0
It would take a lot more than that to hurt your engine unless it was about ready to break anyway. If you are experiencing a bog that wasn't there before, better to tear your carb down and make sure all your jets are clear and clean rather than to compensate by turning up your idle. Sounds like a pilot jet problem. Make sure that the jet is completely open, (blast some air though it) and then make sure that the pilot screw is adjusted correctly. I like to remove that screw and blast some air through the circuit, then put the screw back in and readjust it and the idle screw. If that doesn't help, then you maybe should look for intake air leaks. :nod:
