Were are the diodes typically??

[eBoyDog]

I'm traced my lights not working to the light switch on my YTM200EK, now after checking the the two other part trikes I have, they don't have the same switch harness so I cant just swap it out but after looking at the wiring schematic I see diodes inline of the wiring and as I have torn into the wiring I have not found anything resembling diodes so in the case of my lighting switch, are the diodes in the switch it's self?

For anyone noticing my past posts, my headlight works when the key switch is in the light postion but not when the engine is running which in tracing the wires, the switch isnt getting power from the line that runs from the magnito coil. The wiring is good and as the switch appears to work, it dawned on me that the problem might be the diode since physically the light switch works when it draws power from the battery circuit (keyswitch in the light postion) but not when the power is drawn from the lighting coil, while I have a flacky coil that im going to replace, it makes sense that as it appears the electical system has had issues as the lighting coil is bad, the regulator/rectifier was bad, why wouldnt the diode(s) be bad too but I can find them to test!

Anyone else seen this or had issues with the diodes in their wiring on the Yamaha's? There are several listed in the wiring schematic as as they are shown inline with wiring colors, shouldnt they be external to the thing s like the magneto, light switch and the main switch? All togather in the complete wiring I see more than 10 diodes shown yet unless they are wired inside the wire bundles, I cant find any!

[wonderboy]

I looked at the wiring diagram from the homepage (http://www.3wheelerworld.com/content.php/209-YTM200-Yamahauler-wiring-diagrams). Is this the same one you are looking at?

On this diagram, I don't see any diodes. The black rectangles are inline connections. Are you mixing these connectors up with diodes? If I'm totally missing this, I apologize. I don't think it is common (I haven't heard of it) to have diodes in the wiring harness.

The only place I know you'll have diodes is in the rectifier circuit (converts the AC current from the alternator into DC current for use by the battery and accessories).

So, can you explain the behavior you see on the two switches again? There is the key switch which is 'Off-On-Light' and then the dimmer switch 'Off-Low-High' (I'm just getting this from the wiring diagram, if this isn't how it is, please clarify). Where are you seeing power come and go from?

[eBoyDog]

I looked at the wiring diagram from the homepage (http://www.3wheelerworld.com/content.php/209-YTM200-Yamahauler-wiring-diagrams). Is this the same one you are looking at?

On this diagram, I don't see any diodes. The black rectangles are inline connections. Are you mixing these connectors up with diodes? If I'm totally missing this, I apologize. I don't think it is common (I haven't heard of it) to have diodes in the wiring harness.

The only place I know you'll have diodes is in the rectifier circuit (converts the AC current from the alternator into DC current for use by the battery and accessories).

So, can you explain the behavior you see on the two switches again? There is the key switch which is 'Off-On-Light' and then the dimmer switch 'Off-Low-High' (I'm just getting this from the wiring diagram, if this isn't how it is, please clarify). Where are you seeing power come and go from?

Now you point that out, you are correct and I feel like an idiot! I do electronic engineering and I totally over thought the wiring schematic. The diagram you listed I believe is the one I'm working with but mine is layed out differently as the one im using is from the owner's manual which I scanned and then added color according to the wire colors, both appear to be the same just in a different formats.


Ok, the problem I have is this:

The headlights and tail light are suppose to light up if the left handle control is in the hi or low postion while the engine is running. Mine does not. Now what does work is when I turn the keyswitch to light postion and when the left handle light switch is in the hi or low postion, the headlight works (this is the proper function according to manual).

I have continution from the red/yellow wire which supplies power from the magneto all the way to left handle switch. At that point I point can't get a connection to either hi or low beam wires to the head light. What I can't yet figure out is why and while it's only the headlight it's driving me crazy. This whole trike seems to have been zapped as I'm working on several other issues such as starting problems which per the Clymer manual the ignition coil doesn't test within the proper ohm range and the regulator was also toast when I got it.

Im going to study the wiring again tomorrow and see if I can figure it out better and im going to swap out the lighting coil with a used one I have from a couple part machine.

[Bungle]

I think it may have a broken lighting coil. As you said the regulator has gone burnt out?..When the bike is started I think all the power is being drawn Down to negative causing the lights not to come on

[eBoyDog]

If that is the case, were is the cdi getting it's power to run, off the battery? I put a new battery in it and the electric start works.

[wonderboy]

I'm still contemplating your lighting issue (wiring and switches), but a quick answer for your regulator: Hopefully you have a multimeter. Put it in AC mode and measure the +Battery line with the engine running. You don't want to see much of an AC voltage (you may see a fraction of a volt AC, but that is ok). As long as the AC voltage is tiny, it means you have a good rectifier. Then, measure the DC voltage. Typically, you should see something around 13.5 volts which means your electrical charging system is putting out good power.

[eBoyDog]

Alright, I found and fixed one problem. The left handle light/dimmer switch wasn't working correctly, I was getting power though the blue black wire from the ignition but no connection from to the blue wire from the yellow red wire that supplies power from the magneto. After taking the switch apart and cleaning it, it now works. The switch has four contacts with two on each side of a sliding block. One side switches the blue\black wire to the headlight (that receives power from the keyswitch "light" postion and the other side switches the blue wire to the yellow/red to the headlight and the tail light (this circuit is powered by the ac powe4 off the magneto.

In my situation before I fixed the switch this explains why I wasn't getting power to the taillight or headlight when the engine is running. Now I may have a issue with the lighting coil but I will see what happens after I get everything back together.

This trike has a laundry list of problems, with one marked off I can now move to the next which is the ignition coil so i'm replacing that while I have the tank off. Not to say I still may have carb problems with my cold starting problems but since I have extra used parts I might as well swap the coil and even the CDI.

Oh yes I have a meter and I have tested the battery, sometimes I got the right voltage with the engine running other times not which goes back to my flaky lighting and charging coil and that may be the wiring., not the coils themselves since sometimes they work and other times not.

I should upload my user manual wiring schematic which shows what appears to be diode that explains my confusion! The Clymer diagram shows it better and states in the legend that those are connections rather than my misdirected idea they were diodes. My electronics knowledge is good but I shouldn't have thought too hard about it before I posted my question!

[wonderboy]

Don't feel embarassed by it... I'm regularly involved in electrical troubleshooting of vehicles at work. On one occasion, we had three engineers and one technician pouring over the wiring trying to figure out what our issue was. 30 minutes later (probably more) we discovered it was a blown fuse. Sometimes having a little (or a lot) of knowledge on a topic makes you miss the simple things. :beer

[eBoyDog]

Well my lights work now with the engine running, not very bright headlight. I put my meter on it and had something like 3 volts dc, switched my meter to ac and I think it was something around 5 volts ac.

Now can someone explain what the two coils in the Yamaha ytm magneto do? By name I assume the lighting coil handles the lights and can I safely assume the charging coil provides power to charge the battery?? If this is the case, does the CDi run on AC power or DC? This is the really the first atv type engine I have ever gotten into, while I know some about small gas engines, I have a big learning curve on this Yamaha.

Btw, when I put the meter on the battery I get a little above 12 volts (12.86 but nothing like it should) indicating I'm getting a small amount of charge, it will almost go to 12 volts at high rpm but won't reach 13 volts.

Thanks for the help!loo

[wonderboy]

I think everything you look at downstream of the regulator should be DC voltage only. The presence of AC (I think) indicates a failure of the rectifier.

Pull up the service manual (there is a good Clymer one) at this link: http://www.oscarmayer.net/atc/manuals/ .

You are correct, the lighting coil powers the headlamp and taillamp, the charging coil provides the power to recharge the battery. The CDI uses the regulated 12V power, not the AC directly from the magneto. There are connection to the mag, but these are the triggers to fire the spark plug, rather than power feeds to the CDI.

Chapter 7 of the Clymer manual has a bunch of electrical checks. For the lighting coil, it gives you the voltage levels you should see at different RPM's. They say the headlight voltage should be: greater than 11.3 at 3000 RPM, and less than 18 volts at 8000 RPM. (basically it should be between 11.3 and 18).

Also, they give the resistance spec on the coils, which can be used as a basic check of the health of the coil. The lighting coil is the yellow with red stripe wire and the black wire. The lighting coil is 0.34 ohms +/- 10%. The charging coil is the white wire and black wire (black must be common to both). The charging coil should be 0.4 ohms +/- 10%. I find measuring this low of a resistance is tough to do accurately unless you have a good meter. Also, the numbers given in the manual are at room temp. If you are measuring this outside in the cold, the values will be lower.

With regards to the charging, this could be limited by your battery. If your battery isn't topped off on charge, then your charging system won't be able to get the voltage up right away (eventually it will if it is charging). Another way is to put an ammeter inline between the battery and the battery line to the charging system (NOT on the heavy gauge lead that feeds the starter, you'll blow the fuse to your meter when you crank the motor). The book says you should have at least 0.7 amps at 3000 RPM.

Sorry for so much info. This is all just from the manual, so grab that on-line at the link and take it slow from the top.

[eBoyDog]

I'm still contemplating your lighting issue (wiring and switches), but a quick answer for your regulator: Hopefully you have a multimeter. Put it in AC mode and measure the +Battery line with the engine running. You don't want to see much of an AC voltage (you may see a fraction of a volt AC, but that is ok). As long as the AC voltage is tiny, it means you have a good rectifier. Then, measure the DC voltage. Typically, you should see something around 13.5 volts which means your electrical charging system is putting out good power.

I'm seeing a very small fraction of a volt of ac on the battery as you describe when the engine is running and as I have a new regulater, that I expected is ok, not seeing as a described much over 12.75 with the engine at idle and it increase very little at higher rpms.

[wonderboy]

Give the battery time to charge. If the battery is drawing a lot of current (to charge), the voltage won't climb that high initially. Think of the battery as a big capacitor. It takes some time to charge it up, and while it charges, the voltage will slowly climb. Give it more time, or switch to amps mode and see if your putting current to the battery through the fused battery lead between the electrical system and the battery.

[eBoyDog]

I think everything you look at downstream of the regulator should be DC voltage only. The presence of AC (I think) indicates a failure of the rectifier.

Pull up the service manual (there is a good Clymer one) at this link: http://www.oscarmayer.net/atc/manuals/ .

You are correct, the lighting coil powers the headlamp and taillamp, the charging coil provides the power to recharge the battery. The CDI uses the regulated 12V power, not the AC directly from the magneto. There are connection to the mag, but these are the triggers to fire the spark plug, rather than power feeds to the CDI.

Chapter 7 of the Clymer manual has a bunch of electrical checks. For the lighting coil, it gives you the voltage levels you should see at different RPM's. They say the headlight voltage should be: greater than 11.3 at 3000 RPM, and less than 18 volts at 8000 RPM. (basically it should be between 11.3 and 18).

Also, they give the resistance spec on the coils, which can be used as a basic check of the health of the coil. The lighting coil is the yellow with red stripe wire and the black wire. The lighting coil is 0.34 ohms +/- 10%. The charging coil is the white wire and black wire (black must be common to both). The charging coil should be 0.4 ohms +/- 10%. I find measuring this low of a resistance is tough to do accurately unless you have a good meter. Also, the numbers given in the manual are at room temp. If you are measuring this outside in the cold, the values will be lower.

With regards to the charging, this could be limited by your battery. If your battery isn't topped off on charge, then your charging system won't be able to get the voltage up right away (eventually it will if it is charging). Another way is to put an ammeter inline between the battery and the battery line to the charging system (NOT on the heavy gauge lead that feeds the starter, you'll blow the fuse to your meter when you crank the motor). The book says you should have at least 0.7 amps at 3000 RPM.

Sorry for so much info. This is all just from the manual, so grab that on-line at the link and take it slow from the top.

Got the manual and have gone though most the tests, now with the wiring, the lighting coil lead from the lighting coil connects directly to the headlight switch and then to the headlight. As I have read other posts here, most of the light systems run on AC when the engine is running which is why I even tested for AC at headlight after I fixed my switch. This wiring lead is prior to the rectifer/regulator so my logic suggests that its AC power as now im certain I have both a bad lighting coil and bad charging coil since my lights are very dimwhen the engine is running and I'm not getting 13+ at the battery while the engine is running.

Actually, just checked the Clymer book and to test the headlight it states to sst your meter to AC20 to check with for mine I should see 11.3 or more at 3k rpm and 18 or less at 8k rpm. As I haven't worked with AC volt testing, by setting you meter on AC20, I'm not sure if that means you are testing 20 volts or less or if that means 20 is a multipler? None the less, I think it's a AC voltage with the engine running.

Now for the YTm200's as I have learned for some reason they have a three postion keyswitch, off, on and lights. Some engineer at Yamaha in the 80's decided it would be useful to be able to turn the headlight on with with engine off, in this mode, it draws DC power from the battery (user manual suggests to never use the keyswitch "light" postion more than 30 minutes or otherwise it will run the battery down (Duh!)

[eBoyDog]

Give the battery time to charge. If the battery is drawing a lot of current (to charge), the voltage won't climb that high initially. Think of the battery as a big capacitor. It takes some time to charge it up, and while it charges, the voltage will slowly climb. Give it more time, or switch to amps mode and see if your putting current to the battery through the fused battery lead between the electrical system and the battery.

My battery is new and in good shape, prior to replacing the regulator/rectifier in knowing the battery wasnt being charged, I have been keeping it on a smart battery charger that conditions regular,gel and agm batteries. Prior to starting and with the ignition off it's sitting at 12.7 volts and dips a little below 12 when starting. Im confident that my battery is good and charged prior to even trying to start so now IF my charging coil is putting out proper power, I shouldn't I see 13+ volts at the battery while even idling?

Now while there is voltage check for the lighting coil, I couldnt find one for testing the charging coil output prior to the regulator, the book just refers to checking the battery voltage and the ohms of the two stator coils. I couldn't find anything about the proper ac output voltage of the charging coil.

Of course nothing is simple with me, im using a bigger regulator off a Yamaha bigbear ( I got it very cheap and it was new), it had 3 leads from the stator instead of having only 2 which is intended gor use with 3 phase magneto intead of YTM's 2 phase. After checking the Bigbear's wiring schematic, it is the pretty much the same as the YTM's and i'm only using 2 of 3 stator wires of the Bigbear's regulator. Now with that, I have a really cheap 4 lead China "universal" 12 volt regulator/rectifer that that finally came in yesterday I'm going to test tomorrow if I can figure out which 2 leads go to the stator and which lead is 12+. I have tried 3 YTM used regulators only to find they were bad before I tried them so after getting burned on used regulators, im trying a better route. In theory the worse I can do with my unorthodox regulator testing is it not working or perhaps blow a fuse. (Right?) I guess there might be a chance of blowing the CDI module but I have three extra ones just in case.

Now if someone could answer my post about OEM nos coils or aftermarket, I can get new coils ordered as I while I have a couple used ones off my part machines, i would prefer to replace it with new ones so I wont have to open up the side more than once as i'm not confident my used parts are very good.

Thanks to everyone helpimg me so far, as I described, as while i'm good with gas engines, these three wheelers are new to me and im learning more every day. BTW my real occupation was in IT data networking and im a retired system analyst so while I may not know much about Yamaha three wheelers, I can tell more than you would want to know in how the internet works!

Thanks again guys!

[wonderboy]

With regard to the charging circuit, my initial direction to measure the voltage is a bit less direct and subject to other factors. The best way to check if you are charging your battery sufficiently is to put the ammeter inline on the battery line (not the heavy gauge lead that feeds the starter, but the lead with the fuse). An easy way is to infact pull the fuse out and use your ammeter leads to bridge the fuseholder (in other words, your meter takes the place of the fuse).

Just see what direction current is flowing.

Put the positive lead towards the loads and the negative lead towards the battery. Then a positive amps reading means you are putting power back into the battery (charging). If it is negative, you are draining.