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My 250R randomly stalls out when downshifing or blipping throttle.

15K views 38 replies 9 participants last post by  sendler 
#1 ·
So after a lot of research I came strictly to this forum to post about this problem and see if anyone has had any luck with a solution yet... I've owned my 2012 CBR250R for almost a year now and its got 12,000 miles on the clock, and I am still facing this issue, so I think we can rule out that it has nothing to do with the break in period on the bike. So here's what's happening... essentially it happens very sporadically and I can't pin point much. The bike has been randomly stalling on me every 3 or 4 rides, and usually occurs when downshifting and blipping the throttle to rev match. I've also noticed it seems to happen more often at the end of a long ride (going 60-70 mph on the highway). I quickly exit the highway and turn onto my street (as I live right off a major highway) and blip the throttle (sometimes clutch isn't even engaged) and the bike will stall out completely. I can almost say with certainty that I remember just coasting down my street in neutral and blipping the throttle trying to get it to happen, and then it died that time as well. At this point it's probably happened 20-25 times and I've owned the bike for the last 2,000 miles. Very frustrating to say the least and it seems as if Honda is denying the issue altogether, despite the evidence found in these forums that says otherwise. Has anyone found a solution yet?
 
#2 ·
My best guess is that the throttle is fully closed before this happens. There are a number of threads about this stalling; the general consensus seems to be that the idle air control valve setting is not quite right. If it cannot be adjusted (can you tell that I do not have this bike?) replacing the valve may be your only option.
 
#3 ·
Yes sir you are correct. Usually happens when opening throttle after it's been closed. I think I could easily get this on video as it's fairly consistent on my bike. I was thinking a quick/easy fix would be a fuel controller and trying out some maps that people have come up with. Seems like the route to go as opposed to multiple trips to the dealer and fighting with Honda, who still hasn't addressed the issue as a manufacturer's problem.
 
#5 · (Edited)
Yes it's been doing it ever since I had the bike. I got an absolute steal on it too. (Paid less than $2000 for a 2012 with just under 10k on it in mint condition and aftermarket parts) I now have a hunch this is because the PO knew about this issue and wanted to rid of the bike. After further reading it looks like the IAC valve should not be touched... not sure on the TPS.
 
#6 · (Edited)
Yes it's been doing it ever since I had the bike. I got an absolute steal on it too. (Paid less than $2000 for a 2012 with just under 10k on it in mint condition and aftermarket parts) I now have a hunch this is because the PO knew about this issue and wanted to rid of the bike. After further reading it looks like the IAC valve should not be touched... not sure on the TPS.
TPS is adjustable. IAC might just need to be replaced if it's not working properly. The trick is knowing if it is or not.

Depending on the price of the part and the difficulty to replace, it may be worth a shot.

I would also run a strong fuel system cleaner through it once per year. Chevron Techron is my favorite at 1oz per gal. It would clean the injector and also remove deposits from the valves and combustion chamber.

Run Regular 87 octane gas, without ethanol if available.

Check the condition of the air filter and the intake opening to be sure it's clear.

EDIT: Does it do the same thing hot or cold? One of our cars has the IAC disconnected because it holds the RPMs up while shifting (extremely annoying). It's only an issue when the engine is cold, when it doesn't idle. Once it's warmed up it idles fine without it.
 
#7 ·
I haven't run the fuel system cleaner yet, I could probably give that a try. The bike runs excellent other than this one little quirk. And this happens when the engine is both cold and hot, in fact it usually happens when hot more often than cold. Usually after I'm coming off the freeway and have been wide open for a good while, and then pull off and in a matter of 2 minutes I'm coasting down my street with throttle closed. I'll give it a quick blip right before my driveway and it has died right then a good 4 or 5 times. I highly doubt that the TPS is the issue but if it is cheap enough I may just go ahead and do it.
 
#9 ·
aside from malfunctioning equipment etc,
there can be a factor of ecu closing off fuel
in response to rapid decel after acceleration
[in my case], as a fuel economy measure..
presumably your highway speed riding [revs]
then throttling off at the exit could mimic
this effect.. try riding as usual but without
rapid full throttle closing,, or coasting..

coasting is a bad habit imo, where normal riding
in gear is possible, including down to slow walking pace..
when coasting you have throttle shut [presumably]
whereas not coasting means throttle open or not shut off..
i replicated cut-out after it happened returning home and to
my park,, ie, accelerating up my sloping street in second
but distance at end of 2nd not far enough to go into 3rd
then stop at my park [chained to a tree in the road]
- so instead of holding high revs in 2nd, i coasted,,
the short distance after rapid decel, throttle off -
this was not a predictable replication, only managed
it once or twice.. so developed the habit of not fully
closing throttle,, even when engine braking down thru
gears [my preferred method of slowing].. simply not
fully shutting throttle off, but leaving it a touch open..
[difference between a normal and a strong handshake]

also, my cut outs faded away after starting correct startup routine
[basically no throttle start, allowing revs to drop from 2000 to 1500]

also whether coincidentally or not, learning here the same time
of correct fuel [91ron/87pon] and also not using ethanol blends..
[it came with a tank of 95ron which i used until learning different]

i just put it down to learning the motorcycle, as usual..
then rode it daily over a year with no problems, until stolen..
no problem with replacement cbr300r, basically same system..
[started with 91ron no ethanol, same riding habits]

agree on checking for anything loose under seat area,,
as this has been the culprit for other members here..
 
#10 ·
I see what you're saying with avoiding the coasting, but this issue has also occurred when downshifting, clutch in, blip throttle to rev match, and then it cuts out. It's only happened like that once or twice I should say, but this definitely isn't something that only happens when coasting.

I'm pretty much a noob when it comes to bike maintenance. I performed one oil change on the bike so far as that was pretty simple to figure out. What "loose" things should I be looking for under the seat?
 
#12 · (Edited)
not saying 'only coasting', but mine cut out
coasting on my street which i replicated,
after aceleration then rapid decel
[throttle off, short coast]

dont leave things under my seat area,
but members have reported various paper
service record, owners manual, toolkit etc..
search using search in user cp top of page
under problems gets lots of hits if you
want specific items reported as
blocking air intake..
 
#15 ·
#19 ·
Yes it does have an aftermarket Delkevic exhaust, just a slip on, still have the cat. I spoke to someone at Honda call center a few days ago about the issue, he said it's likely rider error and blamed me.... of course not wanting to admit that there's anything wrong with the bike's design. He actually seemed mad that I mentioned this forum, but anyhow...

I've been looking into getting a power commander for the bike anyway to squeeze a little more power from this small displacement engine, do you think that would correct the issue, or at least make it a lot less frequent since the bike is tuned so lean from the factory?
 
#17 ·
I'm sensitive to this since most people consider the throttle plate stop on such bikes as an idle adjust screw. But it's real purpose is just to stop the sharp edged, steel throttle plate from digging in to the aluminum housing when it closes. The correct adjustment has the plate actually closed and touching the housing bore.
"Cracking" this open with the stop screw in any engine that has a computer controlled idle air valve won't raise the idle since the valve will be controlled more toward a lesser contribution to keep at the programmed speed. Until you open the plate so far as to completely overwhelm the valve. At which point throttle position sensor will no longer see the correct closed position and can set a code.
 
#18 ·
I'm just providing my findings.
So when I bought the bike new in 2013, I also found that the bike would give a popcorn pop and then stall while I blip the throttle at a robot (traffic light - we say robot in South Africa)

I also found that it would happen more often when I had the clutch out in neutral. So just trained my self to blip the throttle less and I can say my bike in this year has only stalled twice due to me blipping the throttle. I'm pretty sure its due to a missfire within the cylinder. These bike run lean as is.

My bikes history,
The bike is my daily commute to my work about 34 km on about 30km of highway. (120km/h speed limit) it has 35000km on the clock and is serviced every 4000km by yours truly and serviced by Honda every 12000km . I do run fuel cleaner ever 12000km just before I take it to Honda.

So in the end change the way you ride to suit your bike and it will love you for it.

Ride safe all.

Sent from my SM-G950F using Tapatalk
 
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#21 ·
I feel there could be flooding of the engine due to blipping the throttle IF the bike had done about 20 K Kms or more. The Valve Overlap causes some amount of exhaust gases to return into Inlet and this causes it to deposit in the manifold upto the throttle blade. Over a period of time this forms a thin soot at the inner side of the throttle body , closing the gap under the blade within..ie., the gap between the throttle blade and body should exist for the engine to breathe air through at idle. If this gap reduces then the minimal air is cut off, and so when the throttle is closed the AFR suddenly gets rich and engine shuts down. Cleaning the throttle body, esp under the blade's lower section of this soot formation can solve this problem.
Otherwise try the Secondary Earth Wire Modification.
 
#24 ·
@ Shisosin , Normaly The Carburetor cleaner spray is used for cleaning the Throttle body deposit..A small burst of spray ,aimed at the under side of throttle butterfly valve ( when engine is idling) will clean this small deposit...The engine can be revved later to 3 K RPM and 2~3 short burst will ensure further cleaning.
@ Sendler there will always be a small gap under the throttle butterfly valve for engine air breathing at Idle. In CBR250R The Air Valve is used mostly for Cold starting purpose and till the engine achieves the operating temperature......Only in 4 wheelers the air valve is used to adjust for maintaining the engine RPM under different load condition through a stepper motor actuating the valve.( like AC , Headlights ,etc.)
Still in 4 wheelers also if the Air Gap under the throttle valve is closed , initially there will be hesitation in off the block start, till the same problem of engine shutting down when accelerator is released will happen when the smoke deposit manages to close the air gap...Which is why Throttle body cleaning is a must in cars every 60~70 K Kms, and ofcourse depends on valve overlap time ,and health of the engine.
 
#25 ·
I haven't looked at the CBR20R in detail but can assure you from my vast factory training as a Mercedes tech that in Bosch CIS-E fuel injected systems in cars with electronic idle air valves that the throttle plate is adjusted to be totally closed and touching the bore all the way around with no air bleed of any kind. The set screw is just there as a stop to prevent the plate from constantly digging in to the aluminum bore. Idle speed is under complete control of the electronic idle air valve with no air coming past the throttle plate. I suppose idle air valves could get sticky but their "rest" position is never closed during any off idle of the thorottle as signaled by the throttle position sensor. If anything the computer positions the valve at a slightly higher flow postion as it waits to come under control after a once again closed throttle.
 
#26 ·
Sendler I agree with your points...like you said if the valve closes fully it will dig in to Throttle body and will be difficult to open normally...for this reason the set screw is adjusted to have a small gap to stop this jamming of the valve... this gap + idle Air set screw + the Idle control Valve to-gether decides on the Air volume for stable idling..When this small air leak in the throttle butterfly is blocked , then the total air volume reduces. The air ,through the gap is being sucked by the Engine vacuum at high velocity, and so is large enough to make a difference in idling quality and sudden increase in AFR to rich condition ,when throttle is closed.( if blocked with soot formation)
 
#27 ·
if the valve closes fully it will dig in to Throttle body and will be difficult to open normally...for this reason the set screw is adjusted to have a small gap to stop this jamming of the valve... this gap + idle Air set screw + the Idle control Valve to-gether decides on the Air volume for stable idling
Not on a car. There is no air gap in the set up of the throttle stop on a Bosch CIS-E car. I don't know about this bike.
 
#28 ·
Had this issue on my 2012 reg CBR250R which I bought new. I am now on only 10,000 km and so have used the bike very little but this stalling issue was from the beginning. I went to the Honda dealer to ask if there was a defect and he told me he knew of no such problem. When I finally splashed the cash on a DimSport Rapid Bike piggyback ECU (around 2014 I installed this), the problem completely disappeared and my bike has never stalled once since.
My guess is it is a defect due to ECU programming to keep emissions down.
 
#30 ·
Just looked it up... so is this in essence a fuel controller? I was asking earlier in the thread if a fuel controller might solve the issue. The ones I was looking at (Bazzaz for example) were around half the price though, right around $250. Sounds like the RapidBike might have been created specifically for this issue though.
 
#37 ·
I have found a bike garage with a rolling road that deals specifically with DimSport products. I will get in touch with them soon to try to get some more info about setting up the EVO especially as I would like to install the map switch (1 map for normal use and 1 map for passing annual emissions test).


Burani Moto Srl - Rapid Bike Sevice


The garage is near where I live in Italy. However it will now be spring of next year before I take my bike to them as I have now put it away for the winter.


Thonschopp96 - you will need to wait until them for more info from me.
 
#38 ·
Just a quick update on the Dimsport RapidBike Evo ECU:


I went to the garage near where I live to get help trying to set-up the RapidBike module but was less than successful in that when the mechanic saw it was fitted to a 250cc, he showed almost complete disinterest and suggested that I just play around with the software myself at home. This is kind of what I had suspected might happen all along.
So in the end I am doing just that. I have bought a double map switch and installed this and have set up the two maps so that one is biased to fuel economy and the other towards performance/acceleration. The auto-learning process is now starting from scratch as the map switch installation deletes the old map (auto learn cycle had already been completed before with 6 hours riding).
The difference when flicking the switch is quite noticeable although I will have to wait a bit longer to see if there is a noticeable fuel saving benefit in economy mode.
 
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