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Discussion Starter · #1 · (Edited)
Hey guys,

So I've totally rebuilt my ZX-12, and have replaced the stock air filters that was already disintegrating with BMC. It's got a Cowley exhaust on it as well, but no PC. Now that everything is back together, the bike stutters insanely when I try to pull away. Even just idling and slowly opening the throttle the bike will stutter and die.
I was super convinced it was a vacuum issue, so I've replaced all my vacuum hoses with silicone hoses and balanced the throttle bodies. It's a bit better, but not as I would like it. When I pull away I have to lift the revs past 2000 to get away.
Now one thing I've noticed when I balanced the TBs was that the second vacuum connector on top of the throttle body was blocked. Nothing in the manual says anything about it. Should these be open or are they intentionally blocked @ factory as this is not the California model. Now I've shuffled the hoses around a bit, so that I've got vacuum on the Intake Air Pressure sensor from Cyl 1 & 4 and the air switch on top of the valve cover gets vacuum from 2 & 3. Even the parts diagrams doesn't have these vacuum hoses on them. Almost forgot. I also adjusted the TPS to factory spec which also made it a bit better.

Your thoughts?

This is the OBD readings. All sensors seem to be in good order.
17152
 

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I could be wrong here, but I think the number 1 cylinder has the vacuum sensor fitted, 2+3 go to the secondary air valve system, and number 4 should be blocked off with a rubber cap. You don't want any of these open to the air.
 

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Hey guys,

So I've totally rebuilt my ZX-12, and have replaced the stock air filters that was already disintegrating with BMC. It's got a Cowley exhaust on it as well, but no PC. Now that everything is back together, the bike stutters insanely when I try to pull away. Even just idling and slowly opening the throttle the bike will stutter and die.
I was super convinced it was a vacuum issue, so I've replaced all my vacuum hoses with silicone hoses and balanced the throttle bodies. It's a bit better, but not as I would like it. When I pull away I have to lift the revs past 2000 to get away.
Now one thing I've noticed when I balanced the TBs was that the second vacuum connector on top of the throttle body was blocked. Nothing in the manual says anything about it. Should these be open or are they intentionally blocked @ factory as this is not the California model. Now I've shuffled the hoses around a bit, so that I've got vacuum on the Intake Air Pressure sensor from Cyl 1 & 4 and the air switch on top of the valve cover gets vacuum from 2 & 3. Even the parts diagrams doesn't have these vacuum hoses on them. Almost forgot. I also adjusted the TPS to factory spec which also made it a bit better.

Your thoughts?

This is the OBD readings. All sensors seem to be in good order.
View attachment 17152
Hi I was wondering how you went about getting that readout. I don't suppose it is as simple as plugging in an obd scanner
 

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your map sensor needs to be hooked up to all 4 tbs on the smaller barbs. only connected to 2 wont be reading properly.
 
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