Folks,

Apologies if this has been dealt with before but I'm new to trials. My 10 year old son and 14yr old nephew are riding beta's in junior divisions at the moment. We've had a few instances of bikes getting stuck on full revs ( for a number of reasons, (dropping,caught cables etc.)On a few occasions the engine kill button doesn't work ( I presume because the engine is so hot at that stage. Can anybody tell me what is the best method of stopping the engine when this happens ?

Some suggestions we've heard are "turn the bike upside down", "Rip the carb off asap" or "block the exhaust with your hand and choke the engine"

Any help would be appreciated,

Thanks

Blocking the exhaust can work or flick the plug cap off, if it's still going pull the fuel hose off rather than go for the carb.

Block the exhaust with your boot, not your hand.

I think pulling the fuel line off will create more serious problems, i.e. possible fireball consequences!

Do not touch the plug cap at any point, never mind full revs. You'll get a massive shock.

And do not pull the Fuel line off, you'll probably be ingulfed by a nice big Ball of flames.

Kill switches don't really work at full revs, because the bike creates it's own spark to run off, and the switch dosen't cancel it out.

( Thats a basic description )

Best way is stick your hand over the exhaust and choke the engine.

Or if it's in gear and revving, tap the back brake to stall it.

but choking is favoured method!.

Edited September 30, 201015 yr by hrc_monty

Putting the choke on can sometimes work.

Do not touch the plug cap at any point, never mind full revs. You'll get a massive shock.

And do not pull the Fuel line off, you'll probably be ingulfed by a nice big Ball of flames.

Kill switches don't really work at full revs, because the bike creates it's own spark to run off, and the switch dosen't cancel it out.

( Thats a basic description )

Best way is stick your hand over the exhaust and choke the engine.

Or if it's in gear and revving, tap the back brake to stall it.

but choking is favoured method!.

Where's your sense of adventure?

Put the bike in top gear and slowly let the clutch out. It will stall the bike.

These will work but which one to use depends on circumstances

Turn fuel tap off and put choke on - takes a while to work

If it is in gear and you can get to the rear brake pedal, try stopping it with brake. Top gear works best if you can shift the gears.

If you can flip it completely upside down without getting tangled in the chain or rear wheel, it will stop immediately with no further effort

If you can do it without burning yourself, block the exhaust outlet. A bunched up cloth/shirt usually works well for this.

So far I have stopped three runaway motors (Beta, Beta, Beta) by inverting the bike, another by using the rear brake (TY250Z) and another by blocking the exhaust outlet (Beta). A friend of mine suffered a piston/bore seizure using the turn-the-fuel-off-and-walk-to-a-safe-distance technique.

Removing the plug cap will not stop a motor if the kill switch wont and is incredibly dangerous regarding risk of stopping your heart and breaking your arm

Taking carby off will be effectively giving bike full throttle for brief period before it stops

I was riding in a trial many years ago and the rider infront fell off and couldn't stop his bike from reving, a number of us were trying to help when a young girl who was also riding calmly walked up and stopped the bike with her gloved hand over the exhaust.

She just shrugged and told us that was what her Dad had showed her to do!

Clutch in..

Select top gear..

Back brake on..

Clutch out..

Motor should stall nicely.

I've seen the 'muffle-the-muffler' not work at all?

Simply flip the top off the throttle assembly & take the cable off the plastic disky circly thingy.

Simply flip the top off the throttle assembly & take the cable off the plastic disky circly thingy.

is that the technical term

Thanks a million lads for all the replys, at least now I have a couple of options ( instead of hoping around with a panicked look on my face !!!!)

As Perce said, throttle cable off works well, lying the bike on its side can also work most times and top gear brake full on is the quickest although can put you in an awkward position if it wont knock off.

If you can, turn the bike totally upside down. Big John told me that one a few years ago and I can confirm that it stops the engine very quickly!

I've not had great results trying to choke the exhaust, apart from a burnt hand. Pulling the plug cap doesn't usually work either as the bike is basically running like a diesel by compression ignition. If you can't get it upside down then trying to stall it is probably your best bet.

Oddly, never had or seen it happen on a 4 stroke, maybe not got a high enough comp ratio.