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Cbr500r engine swap but a single missing wiring placement

1K views 2 replies 3 participants last post by  timur 
#1 ·
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Hello this piece is from the cbr500r 2021 model engine. Out of desperation i recently did an engine swap from a totaled 2021 engine for a cheap 2014 engine I found off ebay. After rewiring most components i have not gotten to far as i am taking my time to look over things and make sure im doing it right(if you are wondering no a dealership would not do this and i asked, they simply would not want to be liable.) So down to this, so on this picture is a part that id completely excluding on the 2014 model found inside the 2021 engine. Really all i wanted to know is, what and how important is this piece? Does it make the last steps of rebuilding the bike more complicated than I thought? Like ordering a completely new harness or can I just ignore it? I would rather not assume to ignore this and finish up what I've done. Any possible answer is very much appreciated.
 
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#2 ·
It's the gear position sensor; the dash will show which gear you're currently in and will display 1, N, 2, 3...

I can't tell for sure from your post but it seems like your bike is a 2021 and you're putting a 2014 engine in it. If so, you can leave the sensor connected and tuck it up out of the way though the display on the dash will not change. You may get a MIL indicating a sensor fault if the ECU detects that the bike's speed does not match the indicated gear (not sure about that, TBH; my old 2014 didn't have that feature and I don't know what diagnostics the new bikes do on it.)
 
#3 ·
Seems like gear position sensor. On older bikes gear was calculated comparing speed vs RPM and its ignition advance maps depends on gear inserted. So if you leave this sensor disconnected I'm not sure what can occur - maybe ECU will remain with same ignition mapset despite the gear inserted, maybe it will use N mapset, or will enter limp mode using 2D Ign vs RPM ignition chart instead of 3D Ign vs RPM vs TPS charts, or whatever...

However the biggest problem with this engine swap - 2021 engine has different throttle body and different camshafts with different timing, ECU is entirely different too and althought sensors connectors might fit they can have different calibration maps inside the ECU. Ignition and fuel maps are different too for 2014 and 2021 engines. The biggest issue - if this engine has different base ignition advance you can end up with melted pistons at first full throttle acceleration (if it starts).

In other words - it's a **** mess and the outcome si completely unpredictable. It might work or might not and in any case it won't work as well as it should with 2021 ECU. Maybe using 2014 ECU could help but you'll need to rewire it again. Using 2021 ECU with 2014 engine is a russian roulette - nobody can say what will happen.
 
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