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Discussion Starter #1
Changed to a full system aftermarket pipe a few days ago and while great in the low end, it killed the mid-high end.

As described in here.

http://www.cbr250.net/forum/cbr250-...l-system-pipe-has-killed-my-acceleration.html

Took it back to the Honda dealer today and we decided to reset the ECU. They had to check the shop manual how to do it and it was done by unplugging and then reconnecting a small 4 pin connector under the left rear faring.

Finally got to open it up a bit after 20km (busy, wet roads) and still felt a bit slower than stock going up to 7500rpm, then it just takes off - almost like a 2 stroke when it gets to around 8000rpm. Amazing difference. So the results of this pipe and reset ECU shifts the powerband higher up in the RPM.

More testing to be done over the next few day's commute, so will see if I prefer it to stock. But would recommend resetting the ECU to anyone who has changed the pipe.

btw I had done about 120km over 3 days on the new pipe before this.
 

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Discussion Starter #3
The full system is local made so obviously not as much r+d as the big boys like 2bros and yoshi etc.

Those pipes might be more designed to work with the stock ecu so the difference when resetting mightn't be as big as with my one.

But with this the difference is like night and day after resetting it.
 

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Discussion Starter #5 (Edited)
When it's reset it starts off as new, reads the info from the O2 sensor and the ECU maps the fuel accordingly over the first few km.

Apparently anyway... Which is strange as with the new pipe it has shifted the powerband up by about 2000rpm. It really kicks at about 8000rpm now, where the first 3 days with the pipe it was low power from 6000rpm to redline.

Also seems to have more power below 5000rpm.

I would have thought it would have kept the same powerband and just added more fuel to keep the stock F/A ratio.

Should have gotten the page number from the shop manual they had that details which wire to dis/reconnect. They don't actually go to the ECU, but to a wire with a 4 plug pin in it that you can disconnect, then connect again, which was from behind the rear left faring. As they said it was like rebooting a computer after installing a new program.
 

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if i disconnect/reconnect this wire does it void warranty if something was to mess up?

and was it that simple?just unplug the wires,reconnect them,turn the bike on and go?
 

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also if any other details about resetting let me know,like if they bike has to be on or off while resetting etc
 

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wow, very interesting topic, so resetting the ecu means that the ecu gonna start a new reading and adjust it properly?

just heard about this, n if it really works, im rushing to do it now ;)
coz i felt mine was like having a leaner map at mid to high rpm than the stock, its revving but no power is produced, n its not like having a slipping clutch :(
 

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Discussion Starter #9
wow, very interesting topic, so resetting the ecu means that the ecu gonna start a new reading and adjust it properly?
Yes.

just heard about this, n if it really works, im rushing to do it now ;)
coz i felt mine was like having a leaner map at mid to high rpm than the stock, its revving but no power is produced, n its not like having a slipping clutch :(
Yes, mine didn't fully adjust (or adjust at all) for 3 days with a new pipe. After resetting it, it took about 20km before I got to open it up in the high revs and by then it was a different bike.
 

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Discussion Starter #10
if i disconnect/reconnect this wire does it void warranty if something was to mess up?
Seriously doubt it.

and was it that simple?just unplug the wires,reconnect them,turn the bike on and go?
Yes, though it will probably take a few km to set the fuel map to the air flow.

also if any other details about resetting let me know,like if they bike has to be on or off while resetting etc
I went for lunch and when I returned the bike was off and the cables were disconnected, we chatted and they filled me in, then connected the wires, fired her up and I went off for a 30 km spin, after 20km I opened her up and it suddenly took off at 8000rpm. Since then the bike is running great, where before it was feeling pretty bad with just the full pipe.
 

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Bah, I've been trying to tell people this for months.
 

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I have a full Jardine pipe and it feels great. Never had to reset, so i'm assuming they already did it.
 

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I have a full Jardine pipe and it feels great. Never had to reset, so i'm assuming they already did it.
The ECU will learn after a period of time w/o a reset. A reset will make it learn quicker though.
 

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The ECU will learn after a period of time w/o a reset. A reset will make it learn quicker though.
hmm,if it resets on its own why did you try to tell people for months to reset it lol..im confused,if i have to reset it myself or if it reset itself already...:confused: :confused: :confused: :confused: :confused:

redline,do you have the silencer in your pipe?or have you taken it out after the reset?
 

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Discussion Starter #17
I had done only about 120km over 3 days and the ECU certainly didnt 'reset' itself in any way over this time.
 

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This is all common knowledge, its called short term and long term fuel trim, its in all modern programmed fuel injection setups. I never reset it, just let it learn on its own, but like another poster has mentioned this takes longer and IMO probably creates a slightly different set of tables than it would after a reset. As purely an exercise of curiosity I am going to reset our bike now that it has the yosh full system on it (and a week of "learning" with no reset), If I feel any major difference I will report back.
 

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When it's reset it starts off as new, reads the info from the O2 sensor and the ECU maps the fuel accordingly over the first few km.

Apparently anyway... Which is strange as with the new pipe it has shifted the powerband up by about 2000rpm. It really kicks at about 8000rpm now, where the first 3 days with the pipe it was low power from 6000rpm to redline.

Also seems to have more power below 5000rpm.

I would have thought it would have kept the same powerband and just added more fuel to keep the stock F/A ratio.

Should have gotten the page number from the shop manual they had that details which wire to dis/reconnect. They don't actually go to the ECU, but to a wire with a 4 plug pin in it that you can disconnect, then connect again, which was from behind the rear left faring. As they said it was like rebooting a computer after installing a new program.

Someone try this with the Air Filter Cover removal mod please!! The free-breathing engine might produce more power?
 

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Discussion Starter #20
I'm one for experimentation.

How about drilling some holes in the airbox cover (see the 'remove airbox cover' thread), with whatever pipes we're running and then reset the ECU again.

Can always duct them up again if not liked.

I also want to remove the airbox cover with the stock pipe on and reset the ECU again.

Fun times ahead, but probably not for my Honda dealer who's going to have me in every few days getting them to do the same old stuff again and again. :)

Edit: ^ Great minds and that.
 
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