250r throttle sticks and WRECK video

[Dirtcrasher]

Finding the problem isn't too bad, but trusting that 2 stroke again is what got me outta them!

6th gear pinned down my road, downshifted but it was on and I nailed the front bucket of my backhoe.

Must have flew 30'. It's very hard to pull in the clutch, nail the brakes and dump the clutch when your brain is thinking "WTF??". And, sometimes even that isn't enough!!

[86T3]

Come on bretheren, I expect more from you. He hit the kill switch and it continued to run. This has nothing to do with the carb or throttle cable, you have an air leak.

[SteveCZ28]

if its running with kill switch off, and coil wire off, its dieseling. and dieseling happens when you have a air leak. same thing happened to my banshee when i got it. went into the death rev, and nothing i could do but let it blow up

[jakep53]

if its running with kill switch off, and coil wire off, its dieseling. and dieseling happens when you have a air leak. same thing happened to my banshee when i got it. went into the death rev, and nothing i could do but let it blow up

So this may be a dumb question but what keeps it running the heat from the combustion chamber is enough to keep burning fuel? and how does it keep getting enough fuel shouldnt it empty the carb bowls pretty quick? did ya banshee end up blowin?

[El Camexican]

Good read:
http://www.klemmvintage.com/airleaks.htm

[SteveCZ28]

So this may be a dumb question but what keeps it running the heat from the combustion chamber is enough to keep burning fuel? and how does it keep getting enough fuel shouldnt it empty the carb bowls pretty quick? did ya banshee end up blowin?

yes dieseling is combusting off of heat and compression. its dieseling because the fuel mixture is so lean at that point that it doesnt need an external ignition source. doesnt take much to ignite when that lean. which is scary on a 2 stroke. shutting off the kill switch doesnt shut off fuel flow to the carb, so itll keep doing it untill it cools down, runs out of fuel, or grenades.

yes my banshee blew. shattered the left piston, and threw the rod. tore it down to rebuild and saw the left crank case seal behind the flywheel was torn, so thats where it was sucking air

it would be very wise for you to do a leak down test before you go ride it again. you can make a really simple tester for around 10-15 bucks. seal the exhaust and do the test. that will tell you right now if you have a seal or gasket gone as you can watch if it holds or loses pressure via the tester

[CRAZY70MAN]

Man.what a ride!! Not that it would help in that situation with dieseling....but a tether switch can be priceless! Glad you came out in one piece bro...

[90guy]

Sounds like dieseling to me also. Had it happen to an 84 cr250 I was working on. Second start on break in and it just took off. So I leak down tested it and got it together and sold it before I would deal with the fact I was scared to start it.

[Dirtcrasher]

Sounds like dieseling to me also. Had it happen to an 84 cr250 I was working on. Second start on break in and it just took off. So I leak down tested it and got it together and sold it before I would deal with the fact I was scared to start it.

Just a hair off topic but I had a 1994 CR250 and it was the carb slide sticking. The local dealer said they stretched the return springs on both the 93 and 94 CR250; That was the fix. I stretched it and it never did it again but I was always on my mind. Oddly enough, I feel safer on 3 wheels

[El Camexican]

Just a hair off topic but I had a 1994 CR250 and it was the carb slide sticking. The local dealer said they stretched the return springs on both the 93 and 94 CR250; That was the fix. I stretched it and it never did it again but I was always on my mind. Oddly enough, I feel safer on 3 wheels

It must be that dumb luck of mine, but any time I've ever had a 2 stroke with a bad seal or gasket it just ran like crap, never a death rev. As far as carbs hanging open I love push/pull throttles. I've had a bank of single cable Amals hang open for a few split seconds on the strip and scare the heck out of me. The fix was like you said, stretch the springs out.

This thread has made me think about the what if's if it ever happens to me on the trail. I guess it's clutch in, lock rear brake, stop and dump clutch or open the throttle. I don't think I'd have the presence of mind or the guts to just open the throttle to kill it if I was still moving.