Engine breaking (safety follow-up question)

 

Somebody claimed just now the following:

"...shifting down and leaving the throttle closed is a
perfectly valid way of controlling speed..."

In my (limited) experience, when i release the gas
handle and then release the clutch pedal as well, i
get this jumpy leap forward and the engine dies.
I'd like to avoid testing that at an even greater
velocity, as you surely understand.

Am i missing something?

--
Vänligen
Konrad
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Sleep - thing used by ineffective people
            as a substitute for coffee

Ambition - a poor excuse for not having
                 enough sence to be lazy
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Well, yes, something fairly obvious.
With all that mass in motion (you and the bike), if you downshift only ONE
gear at a time, the inertia will keep the engine turning and it will not
die.  It tends to turn faster, actually.

 

Ken Abrams wrote/skrev/kaita/popisal/schreibt :

That is surprising. How can it be faster if it also
can be used for engine breaking?!

--
Vänligen
Konrad
---------------------------------------------------

Sleep - thing used by ineffective people
            as a substitute for coffee

Ambition - a poor excuse for not having
                 enough sence to be lazy
---------------------------------------------------

 

Konrad Viltersten wrote:


You're trying to stop the motorcycle, not the crankshaft.

The faster the engine turns in a lower gear, the more engine braking you get.

As I previously mentioned, engine braking is due to pumping losses as the
piston tries to suck air past the closed throttle butterfly.

A clean carburetor will still supply enough fuel to keep the engine running
with the butterflies closed.

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Message posted via http://www.motorcyclekb.com

 



What kind of motorcycle are you using that you don't feel the effects
of this right away? In my experience, the only time a well-maintained
bike will just die because it was given too much clutch is if it's
going about 5 mph or less.

Maybe we should be more clear: You can't "engine brake" to a complete
stop. Is that what you're trying to do? You need to use the engine
brake in conjunction with your regular brakes. Otherwise, the engine
will stall. You can slow down considerably with the engine, and then
pull the clutch in and finish your stop with the regular brakes until
you're ready to go again...

Does that help? What country are you from? The concept is exactly the
same on a car - and judging from your last name, you probably live
somewhere where manual vehicles are common. If you're driving a "stick-
shift," you will experience the same exact thing. Truckers do it as
well.