locked on full throttle

[Diekatze]

Something strange happened. In a race with plenty of mud, after 30 minutes racing and accelerating at 3/4 gas, no more, suddenly the bike kept going like if I was full throttle. Scared, pulled the clutch and it over reved, thought it was going to blow. Moved the throttle thinking it was locked but no response. Had to kill switch it to full stop. Fast check, no harmed cable or anything. Started it with no problems, ride OK and 30 minutes later...again, , and then... again... 3 times on a single race!
No visible damage anywhere, no locked cable, no locked throttle.... she just "kept going"...
The most bizarre part was killing it, and startin like nothing ever happened without touching anything.....
May be a spooky carb issue? I really have no idea, tomorrow I´m taking the carb off but I´m intrigued....

[hawaiidirtrider]

Sounds like a binding throttle cable.. in mud races stuff usually happens. Youll find out when you clean up and take apart. Were you turning when the throttle raised?

[Diekatze]

Sounds like a binding throttle cable.. in mud races stuff usually happens. Youll find out when you clean up and take apart. Were you turning when the throttle raised?

I cleaned it and fond nothing strange with the cable. The thing is that I wasnt full throttle and locked there, see? And then, killed it, re-started and it was ok....

First time I was starting to brake for a slow turn... missed the curve and ended in the bush.
Second and third time was starting to accelerate straight... If it happened on a turn that whould have been another story

[liberse]

Check your needle to see if the surface is scratched, often stuck throttle is caused by dirt particle (sand) fiding its way between the needle and the needle jet assembly.
When it happens it will often leave marks on the needle outer surface and require its replacement.

Hope this helps.
Liberse

[redbone477]

Safety wire the throttle cable where it goes into the top of the carb.

[robw122]

take the throttle housing apart at the handlebar. look very closely at the little wheel assembly where the cable comes in and connects to the tube. where the cable comes off the wheel and over the little metal cutout to the tube, they wear, they can get a small burr that acts like a tiny fork and can grab the cable and hold it. clean in up with a dremel. the others suggesting dirt on the needle or slide are good checks as well.

[Hyde]

I had a throttle stick on the face of a jump at Millville a couple years ago, bike would have scored a 9.6 in the Olympics for flips, when it landed it snapped the handle bars off, anyway,,,, turned out it was the motion pro throttle tube looked the same but after awhile it developed a notch that eventually wedged in at a really bad time, if your using an after market throttle tube check it.

I have a rule on bikes that the throttle sticks "" SELL IT"" , its the same as a cheating wife, it's always in the back of your mind and it's just waiting for the perfect time to stab you in the back, just move on and be happy.

[Silverfox]

A drop of water on the slide will cause the slide to stick. Once you kill the engine, the vacume from the motor ceases, and the slide drops to closed position. Seen it many times and had my 300 do it 2 days after I washed it. I was 3 mins into a ride. Bit scary

[Ed Lew]

Check for air leaks around carb and barrel. This can cause engine to rev flat out even with a closed throttle.

[Diekatze]

Installed the safety wire on top of the carb (IMO that must have been the issue)
Disassembled and cleaned the complete throttle assembly
Inspected slide and needle, no dirt, no scratches. Lubricated the slide and tps mechanism

The water making the slide stick is reasonable, it was a very wet and muddy long race.

The throttle runs smoother than new. Hope this is it, never want that feeling again.

Thank you all.