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Engine stop problem when stopping

Posted: Mon Aug 05, 2019 9:16 am
by Lee June woo
HI from South Korea again.

I got Engine stop problem.

When I stopped gently, that`s Ok.

When I stopped hardly, Idle goes low and recover after 2~3 sec

When I stopped urgently, engine is stop.

In my guess, Clutch clearance or low battery power is the cause.(my battery is old now, whatever I have to replace it)

but I`m not sure about Clutch clearance. because except that problem, there is no problem.

I need owners help. please leave your advice. Thanks!

Re: Engine stop problem when stopping

Posted: Mon Aug 05, 2019 10:57 am
by Super Steve
I assume that you are pulling your clutch in fully when stopping your motorcycle to disengage the engine from the gearbox. If the clutch is dragging, or not disengaging the engine fully, then the motor will obviously stall (stop running) There may be something lost in translation.

Re: Engine stop problem when stopping

Posted: Mon Aug 05, 2019 11:44 am
by Presto
An engine stalling when the motorcycle comes to a halt from low speed is not uncommon with a large capacity four stroke single cylinder engine.

To continue to run at low engine speeds an engine needs a certain level of torque, twisting or turning force, or, in other words, a certain amount of rotational mass. The tendency of rotating mass is to continue running (‘mass in motion tends to stay in motion’ and ‘mass at rest tends to stay at rest’).

The flywheel provides rotational mass, the torque to keep the engine turning at low speed. This becomes more critical when the engine throttle is closed and the engine is not producing power but relying on the mass of the flywheel to maintain rotation.

As the engine speed decreases it will reach a point when momentum is lost to such a degree that the engine will stop. This may be noticed as the jerky ride experienced when travelling at a speed far too low for the selected high gear ratio. (At this point stresses are generated that may cause significant damage and ought always to be avoided.)

If travelling in a relatively highly gear approaching a road situation that requires the motorcycle to come to a halt the engine may be reaching the point when it is tending to stall. The low engine speed will reduce the engine’s torque to such a degree that the effect of inertia and the resistance produced by the engine’s compression overcomes the momentum of the flywheel.

The problem is best avoided by changing down through he gears as you prepare to halt and blipping the throttle to maintain engine speed and torque by increasing flywheel mass rotation.

(Obviously if the clutch is not disengaged then the engine will stall when the bike stops!)

Re: Engine stop problem when stopping

Posted: Wed Aug 07, 2019 8:46 pm
by vince
Hi, I had a similar problem, turned out to be the brakelight switch shorting out and killing ignition. Vince