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asphaltcycles
asphaltcycles, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 458
Experience:  I operate a motorcycle dealership and CCS Ducati Race team.
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honda foreman 450 es: I have a 2002 Honda Foreman 450 es with

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I have a 2002 Honda Foreman 450 es with shifting trouble.
Gear indicator would go blank (--) and shift function would freeze. Turn key off and back on shift to neutral and it would work ok untill the next time. I replaced the shift angle sensor at front of engine. The machine shifted with out flaw the first trip. the second trip the down shift started to bother. Up shift is always ok, down shift some times works but most times will up shift or down shift and up shift. to get it to down shift requires multiple down shifts quickly. It does not freeze up or flash codes now. I replaced pcm from honda and no different. When checking with volt meter i noticed orang wire to shift motor has seven volts on circuit even after shift is complete. Remember i have replaced shift angle sensor and pcm both from honda. cannot find any wire harness problems or shift switch problems. Gear position switch tested ok. Please help, this is driving me crazy.

asphaltcycles :

Hello, my name is XXXXX XXXXX I would like to help you today. So you say you are not getting any blinking or codes currently after replacing the listed parts?

Customer:

Tom that is correct. It appears the computer is not recognizing any problem. I diagnose car electronics for a living, if this was a car i would think it to be a harness problem or failed part passing power where power is not supposed to be. But i am not familiar with the "shift stratagy" of the program to know if this voltage is ok or not. I noticed the feed back wire of the angle sensor has 5 volts present when un plugged, is this normal? Also if i disconnect the shift angle sensor the voltage at the shift motor goes away but will cause the computer to go into fault mode and freeze shift function.

asphaltcycles :

The manual does not say what the voltage should be, but it is working properly if it throws a code when disconnected. You are to the point now, where I suspect the programming or physical fault of the ECU could be to blame.

Customer:

The angle sensor and pcm are new. this shifting problem is exactly the same with both pcms old or new.

asphaltcycles :

Exactly. You've changed every sensor that would alter the shifting programming, so its getting all the right parameters, but still failing to work properly.

Customer:

I did have the shift motor apart. The inside is clean, armature and brushes look good. I dont believe any thing is wrong there.

asphaltcycles :

More evidence that its programming. You could ask the dealer if there is a way to flash the ECU with a fresh program. If its software related, that will solve it. I know they do it for the larger motorcycles, not sure if they have the file for the atv's

Customer:

I believe the pcm is pre programmed from factory, plug and play so to speak.

asphaltcycles :

It is, but the file can corrupt over time. Its common to motorcycles. ATVs have it too. I talked with a guy with a racing quad, and it happened to him last week. He could not flash it, had to replace, and it worked perfectly.

Customer:

I still wonder about the voltage at the shift motor wire. The orange wire has 7volts present unless in fail mode. If this motor is switched forward and backward by pcm i would think the voltage would follow the "last shift" or not be present at all. There is an audible difference in the shifting up and down. up is a solid click, the down is a rapid click as if circuit is being interupted or cut short. And this is confirmed with a volt meter. the up shift has a clean distinct wave form while down shift has a sketchy or blurred wave form.

asphaltcycles :

So its not sending enough voltage, or long enough for the down shift to solidly go.

asphaltcycles :

That signal is sent from the ECU

Customer:

Past experience is making me believe some thing other than the pcm is at fault.

asphaltcycles :

I've been through a lot of these, and that's my advice. You could continue to change parts over, but you are only chaning inputs to the PCM. Its interpreting those, and sending outputs. One of your outputs is the incorrect voltage to flip that motor strong enough to actuate the downshift. Nothing will change the "trigger" to get it to move. Its being told the correct thing to do, its just not doing it.

asphaltcycles :

Did you still need help on this? If not please rate my service, and it will close this question, but remember you can always come back to this page after rating, for more info.

Customer:

I HAVE SINCE FOUND THE PROBLEM AND I NEVER WOULD HAVE GUESSED IT. LAST NIGHT I READ A BLOG ON LINE FROM A CANADIAN GUY WHO SAID HE HAD ONE WITH 27000 KILOMETERS ON IT! AND RUNS IT IN SNOW AND WINTER.... HIS ADVICE WAS IF ALL SENSORS AND WIRES CHECK OK ITS THE SHIFT MOTOR. THEY WORK ON ONLY 6 VOLTS. I REMOVED THE SHIFT MOTOR OFF MY 01 FOREMAN AND TRIED IT AND PROBLEM IS GONE. PULLED SHIFT MOTOR APART ALL I COULD SEE WAS SOME CARBON TRACKING BUILT UP ON THE COMMUTATOR. TOOK TO LOCAL STARTER SHOP AND HAD THE COMMUTATOR CLEANED UP ON HIS LATHE AND PUT BACK TOGETHER ON THE 01 FOREMAN. TOOK IT OUT AND IT SHIFTED OK. ALL I CAN FIGURE IS LOW VOLTS (6-8) AND CARBON TRACKING ON COMMUTATOR TRICKED PCM INTO SHUTTING CIRCUIT DOWN. NOW I HAVE A GOOD USED PCM FOR SALE! CHEAP TOO! THANK YOU FOR YOUR RESPONCE.

asphaltcycles :

No worries! I'm glad you found it. That is a one in a million issue, with that signal tricking the PCM. I'm so happy you resolved it.

asphaltcycles :

Please take the time to rate my service, and it will close this question. Remember you can come right back to this page and ask any and all questions motorcycle/atv related. -- Tom.

asphaltcycles :

Poor service? I diagnosed it by the book. I'm sorry the problem was different than anything the book had, but I don't think poor service is warranted. How can I help you to bring this to at least ok service?

asphaltcycles :

Vern, are you there?

Customer:

i dont like this rating system. i appreciate the effort to help with my problem but as usual the problems i have are abnormal. sorry yes i am. i dont think your service is poor, just wasnt a fix for the problem. the rating should reflect fix or no fix.

asphaltcycles :

Yes it should. But so you know.... poor service deeply hurts my service rating. Its disproportional to the excellent. Its about 1 to 5. As in, every 1 poor takes 5 excellent to overcome. OK service is the middleground that neither helps, nor hurts.

asphaltcycles :

I am deeply sorry that by the book, it did not located the issue with the servo, its an odd issue thats for sure. I'm just hoping you recognize that I tried my very best to solve the issue, and make you, the customer, happy.

Customer:

i have no problem changing the rating, how much will it cost me?

asphaltcycles :

It will not cost you anything. If you have paid the subscription, or the one time fee, its already charged by JustAnswer. Its held by them, and I am not paid until the issue can be resolved.

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