I have a 2001 450 Foreman ES that has had everything go wrong with the electric shift at one point or another. The last straw was last week when the ESP module went out. In the attachment I outline how I bypassed most of the ESP system with 4 relays. I do not have a functional screen on my machine, so I cannot say if you will retain your gear indicator, but I think that you will. The kit for the relays is $9.87 on amazon https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

I did the installation last night and it works perfectly.

 

Do keep us posted on how it works as this could be a big boost for all the electronic shift Honda owners out there. Honda made a big mistake on this electronic shift tranny but it has been slow to bite them in the behind due to name recognition, to many out there buying on name only and not doing the research.

 

Seen this idea before, it may work, but the reason Honda fitted the angle sensor was so the motor knows when to switch off. On your system the motor runs while your finger is on the button. As the standard set up is quite capable of breaking the selector mechanism, I wouldn't have thought these would last long.

 

You definitely don't want to hold the shift button down, but I'm not real worried about that happening. The way the reduction gears are situated, it can only turn so far each way and I don't think it has enough *** to break something there. As far as the motor being damaged internally by getting power but not being able to move, that could happen, but I think about it like a trolling motor getting bound up in weeds while the switch is on and sometimes I can't get to it right away. Another thing that may be good or bad, Honda says to test this motor with 12v, but it is normally shifting with around 6v. I decided not to drop the voltage to 6v because of the amount of carbon buildup that accumulates in these shift motors, and that usually happens when you operate a DC motor on low power. We are going on a long ride Labor Day weekend, I will update how everything held up.

 

I have a 2000 Foreman ES that did not shift. I replaced the shift motor because a post on this forum suggested that would fix it. It didn't, but I found that 2 of the mounting bolts had been left off so I'm glad I did it (with all 4 bolts now). Then I wired up 2 relays and it works quite well.

I don't think the motor will break the selector gear, but the motor could burn out if it stays on too long. I bet the ECU has a 1 second timer to prevent that possibility. So I make sure to use quick presses only, and sometimes it doesn't shift so I have to retry.

Here is how I did it:
If unable to fix ECU, wire up 2 SPDT relays to shift switch instead
Motor leads go to middle of each relay, NC goes to Ground, NO goes to 12V
Shift Up activates one relay (to switch to 12V), Shift Down activates the other relay
Cut 3 wires on handlebar going to shift switches and crimp on wire extentions,
put 12V fused new wire on Vcc wire (blk/red),
add extentions from shift up (whi/blu) + down (whi/yel) to battery compartment
Add 2x Relays (12V 30A) to battery compartment
connect shift up/dn extentions to relay coils (86 white)
and ground other side of coils (85 black)
NC (87a big red) goes to battery ground
NO (87 big yellow) to 12V battery
(fuse optional as relays will burn out if shorted)
Run 2 wires from shift motor to battery compartment relay center pins (30 big Blue)

Main purpose of ECU is to send 12V+Ground to shift motor until it shifts
ECU Verifies actual gear shift occurs via angle sensor then Stops Voltage
And prevent shifting out of neutral when idle too high
And prevent shifting into reverse unless reverse switch engaged
And send Gears 2,3,4 signal to combination meter
NONE of those functions is CRITICAL, except maybe Stop Voltage when it shifts?
So BE CAREFUL when shifting - DO NOT Hold button down, quick press only.
WARNING - It is possible that holding the button down too long may burn it out.
The motor shifts gears by turning the same shaft as the manual shift tool
and that is the same shaft as the non-ES foot pedal shifter
the shift shaft disengages the clutch and rotates the shift drum
then a spring returns the shaft to center.

 

"I don't think the motor will break the selector gear"

I have fixed at least half a dozen ES Hondas with broken selectors. Usually it is the pawl that moves the star wheel, sometimes the lever that moves the pawl and recently a double clutch auto with the stud broken off that keeps the heavy return spring in place. This is as well as all the loose star wheels that I would not put down to being damaged by the shift motor. Never had a burnt out motor.

 

There are 3 reduction gears from the shift motor shaft to the shift spindle shaft.
The gear on the shift shaft is a partial gear (1/8 of a circle) - Is this the Pawl
you mentioned? Or are you talking about the drum shifter?
Is it hard to replace? Did it break after converting electronic
shift to manual foot shift, or was it un-modified?

 

Looking at the service manual, you probably are talking about the drum shifter.
The master arm is driven by the sub-gearshift arm on the shift spindle,
The gearshift plate is driven by the master arm.
The drum shifter, or 7 notch star, is driven by the gearshift plate.

So I assume the gearshift plate is the pawl.
Could this break when someone tries to force the manual shift wrench
with excessive force? On my Rancher sometimes the transmission hangs up
and I have to push and pull the atv a little to unlock it. If someone used
the manual shift wrench in that situation, that might break the gearshift plate.

Still curious as to how hard it is to fix?
Do you have to remove the clutch?

 

Yes the mechanism is in the clutch housing, it is exactly the same as the manual shift versions, but it seems to be the electric shift ones that break the mechanism, though manual shifts do also get the loose star wheel. Did once have an ES with a broken segmental gear in the ES reduction gearbox, and another that broke the end off the shaft that pokes out and drives the angle sensor (how did that happen?). Don't think the emergency shifter caused breakages as 250s, 350s and 450s are then converted temporarily, to exactly the same set up as manual ones, which don't break. All were un-modified ES Hondas. 420s seem a lot less prone to selector mechanism problems than earlier models.

 

It seems to me that a person can press the footshift pedal harder than
the shift motor can turn the shaft. So I am still thinking the shift motor
cannot break shifter parts under normal use. Then I remembered one time
I accidently pressed downshift when I wanted to press upshift, because
I was distracted and did not look down at the buttons. The engine rev'd up
really high, and I almost went over the handlebars because of engine
braking. Boy was I glad that didn't break anything.

Maybe pressing the wrong shift button is what is breaking the shifters?!
That is not likely to happen with the footshift pedal because you don't
have to look at it to know which is up and which is down.

The other issue is the voltage. The shift motor is obviously a 12V motor
as are all vehicle motors. I bet the ECU passes the dedicated 12V high
amperage feed through with an on/off mosfet device without trying
to reduce the voltage. If you try to measure it the voltmeter may not
respond fast enough to show the 12V peak. Note that the 5V Vcc voltage
is used for the control circuits and not for the shift motor.