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Sunday, October 17, 2010

Switchable Power Modes

Electronics aren't my strength but I figured out that I could wire a DPDT (Double Pole Double Throw) switch to change modes between the normal restricted mode and the hacked de-restricted mode. Why bother with a switch? Dutchgixxer has de-restricted his VFR1200 and reports that he considered changing it back to stock because the torque was so responsive in 1st and 2nd gear. His bike wanted to wheelie and spin if he wasn't cautious with the throttle. Also, the inaccurate gear position sensor could get annoying in the de-restricted mode. I figured a switch would be nice if I changed my mind, that way I wouldn't have to go back in and keep changing it back and forth.

I decided to place the switch under the seat. This way it can't be switched on the fly... I will have to stop the bike, take the key out of the ignition and unlock the seat to access the switch. I don't want it to be changed on the fly because if it were changed in 1st or 2nd gear on the fly, the interruption in the signal could cause a fault, thereby triggering an engine light which in itself doesn't have any negative effects but it's annoying to clear the trouble code.

The first thing I would need to do is repair the wiring that I hacked up near the harness. I kept it tidy with shrink-sleeve insulation and wire ties.

 The gear position sensor sits on the end of the shift drum, right next to the shifter spindle. I removed the
shifter linkage and the plastic side cover to gain easier access.

On the inside of the frame spar there is a connector for the GPS. The connector needs to be released from its clip. The group of wires with the woven insulation goes directly into the GPS>.

I spliced 2 lengths of wire into the 3rd gear wire on the ECU side. I would run them up the inside of the frame and under the tank to the battery area.

This is the DPDT ON-ON switch that I picked up from Radio Shack. There are 6 poles. I ran the 1st and 2nd gear wires on the GPS side to the middle poles. The 2 3rd-gear wires ran to the outer poles on one side, and the 1st and 2nd gear wires on the ECU side ran to the other 2 outside poles. Now when the switch goes toward the 3rd gear side, the 1st and 2nd gear wires will be shorted to the 3rd gear wire therefore the ECU will receive a 3rd gear signal when the bike is in 1st or 2nd. When the switch is in the other position, the bike runs normally.

This is the plug coming from the GPS. The first and second gear wires are cut and the opposite ends run to opposite poles on the switch.

This is my crude schematic. You can see that when the switch is on the left side, the ECU (on the right) can only receive a 3rd gear signal.

I drilled a little hole in one of the baffles under my seat to mount the switch. I sealed the 6 terminals up with a blob of silicone and taped it up tightly. The 6 wires were tidied up with some wire ties. When this switch is in the "up" position the first 2 gears are de-restricted.

Here is my switch:

I threw on a helmet and rode the naked VFR up and down my street a few times, stopping in between to switch "modes". The result is exactly what I expected... In the de-restriced mode the hesitation before 5500RPM is gone. Instead, the torque rushes full-on from idle. It's drastically more responsive. It makes the natural restriced mode feel sluggish.


  1. Glad you mentioned the trouble codes because I was going to mount my switch where I can get to it and switch on the fly. Are you certain that it would generate a trouble code? Can a trouble code be cleared without taking it to the dealer? I don't see anything in the service manual - so far. Thanks

  2. I just found the section on trouble codes in the manual. It looks like it may store a trouble code if a fault is detected but will not lite the MIL when the fault is not present. It would store a 41-1 code signifying a GPS fault and it states that the engine should operate normally. I am going to have to try this as I don't care if codes are stored as long as I don't have to look at a blinking light every time I get on the bike. It would be nice to get the full operation of the gear indicator when I want to by returning to stock mode. I will experiment and let you know how it goes.

  3. There is no reason for a faultcode to be generated. In restricted mode de gear signals are switched as well. You have to ensure that it is not possible to tell the ecu that 2 gears are engaged the same time.
    Greetings Dutchgixxer

  4. Sjouke do you think I've got the wiring wrong? I don't think I'm allowing my ECU to see 2 gears at once. Have I missed something?

  5. Is the leftside of the lower of the schematic the GPS side ?

  6. Yep. I'm not sure why I drew it that way... it's just how my brain organized it I guess.

  7. I did the mod at on the GPS side of the connector that remove the restriction in the first 2 gears. Thought that I could always change the GPS sensor for $60 if I wanted to return to stock with no harm to the main wiring harness. I did this a while ago but did not have a chance to really check it out. I just took another test ride on the VFR with a switch mounted near the left hand grip. At first the difference was not obvious, but when I hit it pretty hard in 2nd gear at 3000 RPM then quickly flipped the switch to de-restricted mode - wow what a difference. I thought that it might be only a difference at wide open throttle, 1st and 2nd gear. But it is clear that the stock restriction affects partial throttle settings as well. I suspect that it not only limits the actual throttle position to something less than 100% but also does not permit full timing advance. Bottom line is... big difference in 1st and 2nd gears not only for peak HP at 10k but more importantly at below 6k.

  8. Hi, can you help me with the GPS 5t and 6th gear wire colours to enable derestriction in 6th gear. Corrie RSA

  9. Corrie - RSA. I bought my VFR1200F in Dec 2010, did the mod,s in Oct 2011 at 18000km and now have 24000km on the clock. I have done your GPS mod as above, 1st/2nd gear exelent for urban cycle, 5th/6th gear for top end, after some extensive testing I can report back no problems, 6th gear derestriction allows the bike to run freely up to cut out at 10,600rpm = 288km/ph. Thanks TSK.

  10. TSK, Thanks for writing. I enjoy reading and learn much. I never found an update on how you liked this mod. Which mode do you end up using most of the time?

  11. Let me put it this way Mike: I haven't switched it back to the standard mode since adding the switch. Not even in the rain.

  12. What are colors on gears 1,2,3? in stock harness coming out of GPS?

  13. Sorry it took me so long to reply....

    1: brown
    N: green
    2: red
    3: purple

  14. Thanks so much for posting this; it was very helpful.
    I ended up taking a Zbomb and rewired it for switchable power modes with a DPDT switch.
    Rather than gears 1 and 2 reading as gear 3, I remapped the gear 1 to 5 and gear 2 to 6; that way my feeble mind can discern the difference.