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JayDee

2000 Honda Foreman 450ES no start

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Posted (edited)

I bought a new project over Easter weekend. It's a 2000 Honda Foreman 450ES with a no start problem. Super clean machine, only 3300ish miles. I've worked on a few 450S and Rancher 350ES models over the years, so I thought I knew what I was getting into but this one has me stumped.

First off, the battery was dead. I pulled it and wired in a good car battery I had laying around just for testing purposes. Now I definitely had power, but nothing showing up on the display with the key on.

Started checking fuses, 15A "Light" fuse was blown, replaced that and now the display works like it should. Neutral light is illuminated and electronic shifter functions like it should. All other fuses including the 30A main fuse is intact. Wiring harness appears untouched. Cranks but I noticed the display resets whenever you hit the start button. Tried with the pull cord instead, still no start but the display didn't reset. Strange.

 

Next step, checked for spark at the plug. No juice. Checked the coil wires (grn, blk/ylw) and I was getting voltage, but it would only spike at first and then drop off. Strange.

 

After that, I turned my attention to the CDI box. Pulled the 2 pole connector that runs up to the kill switch and verified that I had battery voltage in the run position and no voltage in the off position. Checked for voltage on the grn/wht wire and blu/ylw, which should be from the stator if I recall right. Very erratic readings at first but eventually settled to near zero. That makes me very suspect of the stator.

 

More investigation was necessary before I go throwing parts at it. I can't believe the stator would be bad on such a low mile machine. I've got a 2002 TRX450S with over 15k miles on the original. 

 

Just for kicks, I swapped in a known good CDI box from a running machine. Still no start and the old CDI box worked fine in my donor machine. So that is ruled out. Swapped voltage regulators from the same machine (both OEM) and cross tested in the same manner. No start on the project, but the donor machine doesn't have any problems with the project parts. Showed a steady 14.5V as well. 

 

So I'm at the point where I've ruled out all of the more common problems. What am I missing? The two things that stand out to me are the display resetting when I hit the start button and the lights not working at all despite a new fuse. Not even the backlight for the display comes on either. Is there a relay somewhere? Doesn't make sense that the 15A light fuse would keep the display from functioning. I'm wondering if I'm onto something there. The harness doesn't look tampered with aside from a horn that someone added at some point, though it has long since been disconnected. Compression seems okay, but not nearly as hard of a pull with the cord as other 450s I've had in the past. Even then, it should still light off with a sniff of ether. 

 

Any thoughts or suggestions would be appreciated. I can get pictures tomorrow if necessary. Thanks in advance.

 

-JD

Edited by JayDee

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Bad connection of the ground cable from the battery at the crankcase would be my first guess 

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Posted (edited)

Yes -- as said above check the grounds -- remove and clean

Grounds.jpg

Edited by Melatv
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Thanks for the suggestions! I wire-wheeled both grounds on the crankcase and the adjacent ground on the frame. Still no spark and screen still resets while cranking. I even clipped my jumper cable straight to the crankcase ground, but no change. 

 

I disconnected the plug on the frame for the stator/pulse generator and plugged my multi-meter into the blu/ylw and grn/wht leads, just to bypass as much of the harness as possible. Getting all of 0.1v AC while cranking. I hate to say it, but the more I dig into it the more I keep finding myself back at the stator. How bad is that job on these? It looks like there is almost enough room to replace it without pulling the motor. 

 

Also, here is my fuse box. The wires toward the bottom were taped off, any idea what they run to? 

0409211233.jpg

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Posted (edited)

If you have a weak or low battery, or excessive draw on your starter, voltage will drop below threshold required to keep display functioning

and will cause it to restart when you crank the starter

This is common issue if you do not have a GOOD battery connected directly to the harness cables

-(i.e using separate battery with jumper cables etc.. you lose quite a bit through the extra cables 

Most of my no spark issues have been a bad voltage regulator, but sounds like you might very well have a bad stator

No headlights would most likely be a bad wire or switch if the fuse is good

When your display is on and headlights are turned on it provides 12VDC to the brown wire on the speedometer harness to illuminate the LED backlight

so you might want to check the wiring diagram and see where that leads you-I am thinking its a switch possibly

Let us know what you find and we'll help you get it figured out

Pretty sure those two wires in battery box area are a light pigtail, color code is same as rear tail light wiring

If you look on the wiring diagram on page 468 you will see there is one green and one brown left open for use on the taillight circuit

AKATV

IMG_6583 (1).jpg

Edited by AKATV
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Thanks @AKATV and yeah, I know the jumper cable car battery hookup isn't ideal, but it was running down my spare ATV battery too quickly doing all of that cranking during testing. So the ATV battery would sit on the charger while I worked on diagnostics. The stator should produce AC voltage while cranking regardless of the battery condition though, if I remember right. 

 

Funny, I worked the buttons with some WD-40 this evening and we have headlights again! Check off one problem. That leaves the biggest one...

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Well that’s good news about your headlights does your display light up like it’s supposed to when you turn the headlights on now

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If WD-40 got light switch working again i'm wondering about kill switch in same housing needing better contact to work?

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Well, today was the day, I pulled the stator and unfortunately it looks like someone has been in here before. Though the stator doesn't have any noticeable shorting going on, I do see chips and wear spots. What do you guys think?

 

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On 4/10/2021 at 5:20 AM, THH said:

If WD-40 got light switch working again i'm wondering about kill switch in same housing needing better contact to work?

 

That is possible, though that wouldn't explain the lack of AC voltage being produced by the stator reading directly from the plug. 

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Posted (edited)

you were checking the three yellow wires  for AC output voltages, is that correct?

I see a lot of these stators get smoked as people try to run these ATVs with no battery or bad battery, then turn the lights on and its just to much for the staor to keep up without a battery in place and the poor stator just gives up the ghost sometimes kills the voltage regulator too

Should be an easy check as per manual to see if its bad

 

image.png

Edited by AKATV

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16 minutes ago, AKATV said:

you were checking the three yellow wires  for AC output voltages, is that correct?

I see a lot of these stators get smoked as people try to run these ATVs with no battery or bad battery, then turn the lights on and its just to much for the staor to keep up without a battery in place and the poor stator just gives up the ghost sometimes kills the voltage regulator too

Should be an easy check as per manual to see if its bad

 

image.png

 

Negative, I was checking for output voltage on the grn/wht and blu/ylw wires that run from the stator all the way to the CDI box. Thank you though, I will do a continuity check when I run back out to the shop. 

 

Also, I can definitely see that scenario roasting these stators, especially the ES models. That said, it makes me wonder how my neighbor's S model is still alive. The battery in his machine has been shot for several years and he has been too cheap to replace it. I mean, the display doesn't even light up when you turn the key, only after pull starting it! 

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2 hours ago, AKATV said:

you were checking the three yellow wires  for AC output voltages, is that correct?

I see a lot of these stators get smoked as people try to run these ATVs with no battery or bad battery, then turn the lights on and its just to much for the staor to keep up without a battery in place and the poor stator just gives up the ghost sometimes kills the voltage regulator too

Should be an easy check as per manual to see if its bad

 

image.png


I just finished this test and between each yellow terminal I was seeing exactly 1.0 Ohm. HMM.

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Any continuity between any of the yellow wires and ground?

if so, the stator is shorted

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Posted (edited)
14 hours ago, AKATV said:

Any continuity between any of the yellow wires and ground?

if so, the stator is shorted

 

Oh sorry, yes I checked that and no continuity from yellow wires to ground. By the book, the stator is good...but I still wasn't getting any AC output on that blu/ylw wire which is why I pulled it. What else could it be? Pulse generator maybe? 

Edited by JayDee

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I would also say that your stator appears to be good buy the book

I have only ever checked for voltages at the three yellow output wires of the stator so I’m not sure about the other check

I would say if the stator appears to be good by the book as well

If you have the feeling that someone was in there before I wonder if it’s possible that they put the wrong fly wheel on there

Just a thought because between the

fly wheel magnets and the stator  that’s really the only thing it keeps from creating those voltages on the stator output

 

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3 hours ago, AKATV said:

If you have the feeling that someone was in there before I wonder if it’s possible that they put the wrong fly wheel on there

Just a thought because between the

fly wheel magnets and the stator  that’s really the only thing it keeps from creating those voltages on the stator output

 

That could be, though I wonder why they would replace the flywheel? 

 

Anyone happen to have one laying around that they could measure? 

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Check your fly wheel and see what the codes are on it you should be able to match it up that way there’s a ton of them on eBay right now just make sure you look at the correct year and model

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Posted (edited)

My gut feeling is , if you didn’t check the three wires for your stator output voltages that most likely that your stator and your fly wheel are good

since it tests good of the machine

Ifyou only checked the green/white and 

blue /yellow Wires that is only only your pulse generator output for the CDI to trigger the spark

I would suggest testing the pulse generator as per the manual as that’s what I’m thinking is most likely your problem

at this point

Edited by AKATV

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Thanks @AKATV for the info on the flywheel and the testing procedure. I was mistaken, I was testing the pulse generator when I did my first round of diagnostics. Silver lining, the pulse generator is actually shot, so I would have had to pull the assembly anyway.

 

Funny though, on my yellow 2000 Foreman 450S, I saw as high as 70V AC on that pair of wires so I assumed it was the stator output. That machine was also a non-runner when I picked it up but it turned out to have just a bad CDI box.

 

Anyway, new pulse generator is on the way, I'll report back when it gets here and I put the machine back together.

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Thanks for the update and glad to help

Lets us know how it goes as I am sure it will all help someone in the future as well

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Well, I have good news and bad news...

 

The good news, the new pulse generator pickup came in yesterday. I installed it and buttoned up the machine. While cranking, my meter was still showing 0.1v AC, same as the old pickup. But, I also orderd an inline spark tester this week, so I tried it out. We have spark! 

 

Now that brings us around to the bad news. We have spark, we have fuel (even ether) and the machine still won't start. I have never seen a machine with so few miles with low compression, but here we are. I should have known given how it is by far the easiest pull start out of the entire fleet. Unfortunately, I don't have time to tear into this motor right now as Spring planting is right around the corner here on the farm, so this one will be parked in the shed for a little while. But I at least wanted to update this thread and let everyone know that the mystery is finally solved. 

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We've had non-stop rain here, so I took advantage of my free time and cracked open the Foreman. Looks like the diagnosis was spot on, she was ran HOT

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0427211317.jpg

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Posted (edited)

Ordered a cylinder kit, got it put back together and running. Here's some new versus old parts. (Note, broken skirt on the old piston was from dropping it on the shop floor.)

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Edited by JayDee
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