Sometimes: engine stalls when downshifting to 1 while holding clutch - Page 2 - Honda CBR250R Forum : Honda CBR 250 Forums
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post #11 of 79 Old 06-09-2011, 10:10 AM Thread Starter
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No stalls today!
Here is what I did different:
- warm the bike for ~5 mins on neutral before riding
- do not skip 2nd gear when stopping, but downshift to it and use engine to brake
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post #12 of 79 Old 06-10-2011, 12:19 AM
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Its fuel injected why do you have to warm it up? I dont and use the cheapest gas, never stalls. Practice your shifting and throttle habits.
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post #13 of 79 Old 06-10-2011, 01:01 PM
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Its fuel injected why do you have to warm it up? I dont and use the cheapest gas, never stalls. Practice your shifting and throttle habits.
Because it's a single cylinder, even 1 misfire can mean a stall at idle. Even in newer cars when you first start it up in the morning a couple misfires aren't unusual.

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post #14 of 79 Old 06-10-2011, 01:35 PM
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Because it's a single cylinder, even 1 misfire can mean a stall at idle. Even in newer cars when you first start it up in the morning a couple misfires aren't unusual.
Guess I got lucky, mine doesnt misfire, doesnt stall, and shifts properly.
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post #15 of 79 Old 06-10-2011, 02:00 PM
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Guess I got lucky, mine doesnt misfire, doesnt stall, and shifts properly.
They usually wont misfire but a very cold engine coming down in rev's from a shift isn't unlikely at all. Like I said, mine's never stalled either but the start up idle is fairly rough IMO, which is very very normal for all engines.

And you asked why it was important to warm it up and I kinda didn't answer that. Well it's all about thermal expansion. The rings aren't sealing properly and the bearings aren't in proper tolerance until the motor is warmed up. They do things to help compensate for it however. Like oval shaped pistons in a circle cylinder so the piston can expand to a perfect circle for a better seal. A piston doesn't expand out in a perfect circle due to design, the part where the wrist pin goes through is going to expand at a different rate.

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post #16 of 79 Old 06-10-2011, 02:40 PM
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Mine idles low for about the first 5-10 seconds then i take off. As I ride it and let the engine warm up I try to be easy on it for the first mile or two.
I guess my point was that him stalling his bike probaly had nothing to do with the engine being hot or cold, was probaly his clutch/shifting and throttle control.
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post #17 of 79 Old 06-25-2011, 09:55 PM
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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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post #18 of 79 Old 08-09-2011, 11:45 PM
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Took it to the dealer today. They were not able to reproduce it quickly and offered to leave the bike with them for the day. I told that will do at 600 mile service.
During today's quick check they did not find anything wrong with bike tuneup, but acknowledged that there might be an issue and reported it to Honda. Now we are waiting for response, maybe there are similar problems already reported.

For now i just release throttle more slow when pulling a clutch, that helps.
Did Honda come back with anything? I just bought mine yesterday and have gotten this problem too when slowing down to a stop with clutch 100% in. Probably happened 5 times?? Once the engine was warm (half way) then I no longer had this issue.

warming up the engine - doesn't this defeat the purpose of fuel injection? I'm very new to all of this. This is my first bike!
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post #19 of 79 Old 08-10-2011, 04:37 PM Thread Starter
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Did Honda come back with anything? I just bought mine yesterday and have gotten this problem too when slowing down to a stop with clutch 100% in. Probably happened 5 times?? Once the engine was warm (half way) then I no longer had this issue.

warming up the engine - doesn't this defeat the purpose of fuel injection? I'm very new to all of this. This is my first bike!
No, don't have any response from Honda on this. Good thing is (as i wrote in some other thread here) that these stalls were happening for me only during first ~200 miles. Now I am at > 2K and it does not happen at all.
What I do:
- warm the bike for ~1 minute before riding.
- use more engine braking when stopping. Now I almost never stop with clutch fully in, but instead downshift and ride on every gear until full stop and have clutch fully in only on complete stop.
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post #20 of 79 Old 08-11-2011, 04:30 AM
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No, don't have any response from Honda on this. Good thing is (as i wrote in some other thread here) that these stalls were happening for me only during first ~200 miles. Now I am at > 2K and it does not happen at all.
What I do:
- warm the bike for ~1 minute before riding.
- use more engine braking when stopping. Now I almost never stop with clutch fully in, but instead downshift and ride on every gear until full stop and have clutch fully in only on complete stop.
I'm no expert here, but when i did my pre learner course (before you are allowed a learner permit) there was a section regarding stopping. And the curriculum and instructor emphasized that when slowing to a stop (e.g. At a red traffic light), the clutch should be held in, u should be in first gear, then when at complete stop, go to friction point in case you need to move asap if there is danger behind you.

But it sounds as though this "problem" doesnt allow this way of slowing to a stop? Glad to know my 250 isnt the odd one out, but still sounds like an issue, especially when during the learner course this wasnt covered, the dealer mentioned nothing like this in his "rundown" before taking it away. Wouldn't mind knowing what Honda actually have to say.
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