Sometimes: engine stalls when downshifting to 1 while holding clutch - Page 8 - Honda CBR250R Forum : Honda CBR 250 Forums
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post #71 of 79 Old 03-08-2012, 02:14 PM
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Sure it's coming from the exhaust, and not the engine breather pipe?



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post #72 of 79 Old 03-08-2012, 04:36 PM
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ill have to find the breather pipe and see if that was a possibility, but it was in sync with the exhaust puffs coming out the end.


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post #73 of 79 Old 03-08-2012, 05:51 PM
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ok i figured it out. its a hole drilled in the exhaust pipe to expel water that collects in the pipe when its cold out.
definitely there on purpose but i still find it strange.
i also found the breather pipe. btw what is the breather pipe for?


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post #74 of 79 Old 04-09-2012, 10:49 PM
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Read about this issue a while back. Bike has 3000 miles and I never experienced this until the other day. I always let my bike warm for a few minutes before I ride. About a two miles from where I the started bike stalled out while downshifting to first when I pulled in the clutch. I happened to be going around a corner and it was a bit of a shock.
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post #75 of 79 Old 11-19-2013, 07:22 PM
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Quote:
Originally Posted by Java View Post
Most modern bikes (including yours) have a "wet clutch". The transmission, and the clutch run in the same oil that is in the engine. On some small displacement bikes that don't make much power at idle, the cold oil that the clutch is running in causes enough drag on the clutch plates to cause a stall at idle even with a properly adjusted clutch pulled all the way in. The only ways around it that I know of are don't let the revs fall all the way to idle as you stop (pain in the rear) or let her warm up for a couple of minutes before you leave.

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It confirms what I've been reading on the net. Thx JP
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post #76 of 79 Old 11-20-2013, 10:35 AM
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mine does the EXACT same thing,and honda said its common......i thought the clutch was going but it was first noticed at just 3000km

i generally keep the rev's up anyway as a habit from motocross...its only when im downshifting in idle it happens ...cold/hot ...whenever.
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post #77 of 79 Old 11-20-2013, 06:35 PM
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in general, our fuel injection system managed by the ecu [onboard 'computer']
is set for maximum fuel economy, thus lean burning [low fuel to air ratio]
plus when the throttle is shut off, together with clutch lever pulled in,
[such as when gliding without engine power] the ecu shuts off fuel
which would otherwise be simply wasted..

the evu is also partly programmed by what inpust it gets from the various
sensors including from fuel system, throttle and clutch..
this includes or is influenced by things such as how you start her up
each time.. as a general rule, start up by switching on the ignition
but not, hitting the starter button for a few seconds, to allow the
system to go thru its own start up process, ready for starting,
then, hit the starter button, without touching the throttle,
then, allow the revs to drop from around 2000rpm
down to 1500 rpm and to settle into a steady beat there
before putting it into first gear and taking off..
do this every time without fail, for consistent input to ecu
of parameters related to throttle, clutch and engine revs..

also, generally, when approaching a stop sign or light etc,
its a good habit and good for the engine during its running in
period, to throttle down in the gear your in, clutch out,
['engine braking'] causing speed in the gear to wash off,
then, clutch in, change down, clutch out, engine brake
in that gear as speed reduces again then do the same
until into second gear..
when approaching an intersection of stop sign ahead
in 5th say, in suburbia, the stop could be over 50yards/metres
away, but i still begin that engine braking as above long before
actually needing to stop quickly.. this is good skills development,
control of your motorcycle, and develops smoothness in gear
changing together with good back pressure in the engine
which helps the engine to wear in mating surfaces
such as piston ring and so on.. a good thing..

when you get to the lower gears esp first gear
its not necessary to engine brake as speed should be low
enough as you approach your stop to simply press down
into first gear, or, alternatively, to come to your stop
in second gear, then just as you come to the stop
shift the gear lever lightly/gently and deliberately
into first keeping clutch in waiting to take off..

[you can also go into neutral gear and clutch out,
if you need to use your hands for something etc,
but best go to first, clutch in, ready to take off]

people have different preferences for stopping process
and different stops and times taken according to traffic
and so on, but this is a good general method to start with,
as it helps with engine running in, helps develop good
coordinated gear shifting and clutch control
and allows you to be in a good gear at sufficient revs
to either stop quickly or to accelerate away as necessary..

doesnt hurt to adjust clutch lever as recommended to make sure
there is some play before taking up engine power thus making
a clean break between clutch and engine when stopping etc..
also you can check your foot position compared to the gear lever
and adjust that a bit either way with the adjustment rod/nuts..

in general, most people take at least some time and practice
to become easily familiar with gear changing and so on..
its very helpful, to find a quiet spot without traffic etc,
or wherever is handy for you, then to just ride up and down
coming to a stop then starting again, riding up thru the gears
and back down again as you come to your stop..

as deliberate practice, rather than thinking about other cars and
traffic situations etc, your brain and all muscles and joints used
for control of the motorcycle, clutch, brakes, throttle, gears etc,
will get a more direct and 'cleaner' input from the practice,
as, practice, and will learn things more easily or 'better'..

other than such practice, which is very important at first,
just riding, is also important in this learning process..
especially on roads with less traffic etc, including
at times of the day when there is less traffic..

the more of this, the better..
even finding a large even surface such as a quiet carpark
or school ground etc to ride up and down, change gear,
stop and start, or to ride around in circles [good practice]
cannot but enhance and accelerate your skills development,
whatever, skills level you start out with..

there could of course be some technical fault etc
with your motorcycle, which you have addressed by
taking it to the dealer.. but there is still this general
advice which is fundamental to riding skills developement,
to actually practice specific riding techniques, especially
throttle control, clutch control, gear changing and
selection and of course starting and stopping..

many members and others have experienced and reported
their new bikes and themselves going thru an initial phase
of less than perfect use of clutch and so on, especially
when coming to a nice smooth stop..

[finally, another good and related practice is to think of
not, putting your foot down when riding, unless necessary,
ie, instead of riding into a stop, practice slowing down
to slow speed, including very slow speed, thus moving
along slowly, feet on pegs, in first gear and using clutch
control to control you continued slow movement,
until you need to put the foot down and stop]

Last edited by shisoshin; 11-20-2013 at 06:49 PM. Reason: typo
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post #78 of 79 Old 11-21-2013, 08:33 PM
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Quote:
Originally Posted by brayon View Post
It confirms what I've been reading on the net. Thx JP
That doesn't really explain anything when the stalls happen at speed. The cold start drag is enough to make the tire rotate slowly, no where near enough to stall the engine.
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post #79 of 79 Old 11-22-2013, 05:51 PM
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since using correct startup procedure [from info this forum]
mine starts up first touch of the buttom everytime
in daily riding going on 2 yrs now..

coinciding with learning of correct startup i also discovered
that this engine is not suitable for ethanol fuel and should
use 91RON [about 86PON] octane petrol..

this ECU managed fuel injection system relies on various sensors
and air valves etc both inlet and exhaust sides thus whatever
startup you use must provide input to the ECU with various
responses.. in very cold conditions the type of oil used
could be, a factor in how the engine responds..
plenty of inet info on oil viscosity/temp etc..
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