posted this up on my build thread as well.

https://cbrforum.com/forum/cbr-600f3...e-p%3D-152895/

short story: basically i'm fightering an f3 and looking to change speedo yet keep the air solenoid functioning rather than cutting it out and relocating the two smaller intakes for the 1 stage. its a question of generating the correct signal.

longer story: ''I'm looking to keep the dual stage ram air but I'm changing the speedo clocks. obviously the speedo plays a part in telling the ecu/air solenoid to switch to the main intake, thusly changing where the vacuum to its 2nd stage. going to be using a db01plus and a hall effect sensor using magnets on the front wheel rather than the front sprocket sensor that the original clocks use. now i may land lucky and just be able to tap into the new sensor wire but i'm aware that theres likely going to be changes in resistance and whatnot that will change what the ecu/solenoid reads thusly the solenoids operation. i see either two things happening, 1. the solenoid won't function. or 2. it will change the speed at which the 2nd stage comes in at. i'm not going to know until play about with it but id much rather keep the dual stage ram air. does anyone have experience in these matters or have any idea as to the tolerances of the hardware?''

 

been talking to someone about circuits and whatnot and thinking about the air solenoid valve, I've got a much better understanding in terms of the terminology of what i need to achieve. basically the speed pickup generates a current which increases with speed, once a certain current is reached (at 12mph) the inducter in the relay switches and opens up the other vent which gives the 2nd stage of ram air. fairly simple. i'm going to need to measure the current at which the inducter switches on the current setup and when i switch my gauge i'll likely have to find or make up an appropriate capacitor and build a relay to accommodate for any variance in when the correct current is produced. the solenoid would still function on the new gauges but theres no saying as to which speed would generate the correct currency to open it. pretty sure i can figure it out.

 

Yup, that's what will do it. If you have the manual, it might have a section that will talk about the voltages for the sensor and relay. That, or sticking a multimeter on it while trying to spin the front rim to 12mph to find out what voltage opens up the solenoid.

What's your reasoning behind wanting to keep the dual stage air induction, exactly?

 

already scouted through the workshop manual to see if i could find any specs on it just diagnostic stuff so they're either not in there or I'm blind haha

you nailed it on the head conrice, bit of a pain in the **** like haha i'll get there though. been doing a spot of reading and anyone with a track bike or naked build seems to just get rid of it and ground the wire out on the basis that 'how much time do you spend below 12mph anyway.' i've also read without it there's a flat spot in the midrange, which isn't exactly ideal. not quite sure as to why there would be a consistent flat spot midrange when the valve operates at 12mph, i do plan on taking it out for a spin with the valve in different states just out of curiosity.

as to why, well if everyone else does it one way the chances are I'm going to do it the other regardless of how awkward =P other than a minute weight loss there is just no benefit to removing it.

also been reading that because the dual stage was so finely tuned for the vacuum that any changes to the air/fuel system is going to make it less effective, so by having aftermarket headers and a slip on it's already messed up.