2008 stalling on decel

[Maui251]

If I pull the clutch in and downshift at anything over 3k rpm, F1 light comes on and bike stalls next time I pull the clutch. It doesn't happen as long as I'm under 3k, which is a nuisance when I'm riding in traffic. Plugged a scan tool in and it's reading a p0507 code, which I'm seeing is a C40 code. Idle is set around 1200. I was told removing my secondary butterfly valves would fix the issue, but that's not the case. Any ideas? 2008 with full Brock's alien head, pc3, aftermarket levers, side stand switch delete

 

[HayaWakened]

ISC Valve Hose disconnected?
When's the last time the air box was opened up?
Got a Gen 2 manual? Try pg. 1D-6
A disconnected ISC valve hose will throw a C40 (amongst others).

Hope this helps

 

[Hayabusa Wannabe]

Maui251 welcome to the forum. Feel free to write in the new owner's forum the history of this bike and the changes you are planning. Some details should help members support you moving forward.

 

[Bumblebee]

Have you tried to disconnect the PC to see if the problem continues? One never knows how things affect these bikes....

My bike acted up once and the first thing I did was disconnect all the add on electrical systems (quickshifter, Bazzaz) and it did the same thing so I eliminated those...I then unplugged and re-plugged each and every harness connector....the problem went away...

Sometimes it's the smallest stupidest thing...but the most frustrating too.

 

[Maui251]

ISC Valve Hose disconnected?
When's the last time the air box was opened up?
Got a Gen 2 manual? Try pg. 1D-6
A disconnected ISC valve hose will throw a C40 (amongst others).

Hope this helps

Hose is connected as far as I know, I'll double check. Air box has been opened within the last 2 months, everything looks good. I do not have a manual, but probably know someone who does

 

[Maui251]

Have you tried to disconnect the PC to see if the problem continues? One never knows how things affect these bikes....

My bike acted up once and the first thing I did was disconnect all the add on electrical systems (quickshifter, Bazzaz) and it did the same thing so I eliminated those...I then unplugged and re-plugged each and every harness connector....the problem went away...

Sometimes it's the smallest stupidest thing...but the most frustrating too.

I was actually having the issue (started in late February) before the PC was even installed in mid April

 

[sixpack577]

Check that the aftermarket lever is not activating the clutch safety switch at the wrong time, or causing it to stick.
Put the stock lever back on and check.
If that fixes the problem, you can likely file or modify the aftermarket lever so it works correctly.

 

[Hayabusa133]

Was this issue fixed? My friend was having the same issue on his 08. He removed the ISC valve and cleaned it, problem went away.

 

[Maui251]

Was this issue fixed? My friend was having the same issue on his 08. He removed the ISC valve and cleaned it, problem went away.

HOLY HELL, 2 years down the road and I'm not 100% sure it's fixed, I had a buddy plug up his scanner, give me the 7 recent codes. Just finished test riding the bike after working on it all night, but no scanner available, so just put it in dealer mode before the ride. Only getting the c40 code and remembered i installed a new clutch safety switch but it's opposite of what I needed, so its like the switch isn't there. Going to install the correct switch and hope it works. Sitting here typing and of the codes from the diagnostic was for the isc valve. So I'll clean that when I replace the switch. All the other codes I was getting were from the STVs being removed, so I installed a healer. I will update after this weekend. So glad I saw this old post, and your reply from 16 months ago lmao

 

[sixpack577]

The incorrect clutch switch will cause issues, as the bike will remain in a neutral map, instead of switching back and forth to a gear map, with less timing and fuel/aka less power.
Eliminating the secondary throttle plates is also not a great idea, as anything more than 94% open causes turbulence in the throttle bodies, the stp's can be tuned in an ecu flash to open at a more efficient rate, but removed, and you will lose low to midrange power.
The bike really needs a dyno tune once they are gone, and the only real benefit is for a big hp drag bike.
Also check the adjustment on the throttle position sensor.
It should be -00
Not _00 and not with the dash to the top left of the 00 either, you want the " - " in the center.

 

[sixpack577]

You can also eliminate the clutch switch, but on a Suzuki, it must be replaced with a relay(to trick the ecu into thinking the clutch switch is still active), as the ecu switches between neutral and gear maps with every clutch pull...otherwise you stay in the neutral map.