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When you pull off the left sude case you will find some case bolts are longer than others–pay close attention! I usually take s piece of cardboard and draw a little cartoon Showing where the bolts should go. Then i poke holes in the cartoon and stick the bolts in the holes

You have to be careful the shifter shaft stays put when you remove the case, right Outlaws?
 

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When you pull off the left sude case you will find some case bolts are longer than others–pay close attention! I usually take s piece of cardboard and draw a little cartoon Showing where the bolts should go. Then i poke holes in the cartoon and stick the bolts in the holes

You have to be careful the shifter shaft stays put when you remove the case, right Outlaws?
there is no left side cover for the shifter shaft on a trx250 recon ?. this is a front to back motor, not sideways like the trx300's are built.
 

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Discussion Starter #64
Thanks for the help! I'm going to order it from Rocky Mountain. What should I do to prevent the new stator from frying like this one did? Should I get a pulse coil just in case? And should I get a new gasket for the stator case? And one final question, how hard is it to pull the motor?

Thanks guys.
 

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Pulling the motor is easy and the manual covers that well.

You will need a new rear crankcase cover gasket.

Replacing the pulse generator is probably optional since you've tested and found it to be good? If you see any damage to it once you get it apart though, replace it. If you have any doubts whatsover... replace it.

As far as exciter coil failure prevention goes, use only OEM Honda ignition coil, CDI and spark plug cable on the bike and gap your new NGK spark plug properly. Also inspect the harness connector plugs for corrosion or overheating evidence and clean them. Slather dielectric grease inside them during reassembly to weatherproof them.

Alternator windings failure prevention is much the same game. Clean and dielectric grease the regulator/rectifier connectors and clean the battery terminals and frame/motor grounds. Use dielectric grease on them as well to prevent corrosion. Also make sure that the battery remains in good condition at all times. When a battery goes bad, the alternator might fail as a result, so don't ever try to run the motor with a dead/junk battery in the bike, or try to run the motor without the battery installed.

Read the manual before you begin work, not after... :) Hollar if ya have any questions.
 

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Discussion Starter #66
Alright. It's apart. took a few days because of a few bottle necks in time from stuck bolts. One on the starter power terminal and the motor mounts.
Anyways, I have a few questions before I order parts. For anyone who has done this before, what are things I should replace while I have the motor open? I know I need a new rear case gasket but anything else? Also any tips for things I should do before the motor gets closed up, things to check, etc? And how do I seal the cable boot that comes out of the case for the stator wires? I noticed there was some silicone stuff filled in but what should I do? Most importantly, what's the biggest thing people usually screw up/break during all of this? I wanna know, so I don't make the same mistakes :big-grin

To add to the MANY questions I keep asking, what do pulse coils usually throw out in peak volts? Mine is around 7v and i'm wondering if that's low. And the one and FINAL question I have is, what even caused my exciter coil to stop working? Isn't the exciter coil supposed to have continuity to ground? Because I'm not getting continuity to ground.

Thanks everyone for your time, it's really helping me ease my conscience. I'm not gonna lie, I'm pretty nervous about all this. I'm usually unlucky with this stuff so i'm trying to make sure I do it right. Thanks again.

I took some pictures, because I'm getting school credit for all this and need proof, so here they are. (sorry one is blurry)
 

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Alright. It's apart. took a few days because of a few bottle necks in time from stuck bolts. One on the starter power terminal and the motor mounts.
Anyways, I have a few questions before I order parts. For anyone who has done this before, what are things I should replace while I have the motor open? I know I need a new rear case gasket but anything else? Also any tips for things I should do before the motor gets closed up, things to check, etc? And how do I seal the cable boot that comes out of the case for the stator wires? I noticed there was some silicone stuff filled in but what should I do? Most importantly, what's the biggest thing people usually screw up/break during all of this? I wanna know, so I don't make the same mistakes :big-grin

To add to the MANY questions I keep asking, what do pulse coils usually throw out in peak volts? Mine is around 7v and i'm wondering if that's low. And the one and FINAL question I have is, what even caused my exciter coil to stop working? Isn't the exciter coil supposed to have continuity to ground? Because I'm not getting continuity to ground.

Thanks everyone for your time, it's really helping me ease my conscience. I'm not gonna lie, I'm pretty nervous about all this. I'm usually unlucky with this stuff so i'm trying to make sure I do it right. Thanks again.

I took some pictures, because I'm getting school credit for all this and need proof, so here they are. (sorry one is blurry)
I can't answer what the voltage should be on the pick up coil. but the rest I can answer. yamabond or hondabond to seal the wire boot. DO NOT USE RTV SEALANT OF ANY KIND !. mistakes folks make: not getting the gear position switch tab lined back up correctly on the plastic switch !. the tangs long end MUST face the letter N that is stamped on the top of the switch !!. prob be a good idea to replace the flywheel oil seal while you have it apart, as well as any other oil seals that are in that area ?!. as for what causes stators to go out ?, running atvs without a battery is the number one killer !. or a bad reg/rec will kill them. never..EVER...run an atv without a good battery..or no battery at all !..THEY MUST HAVE A BATTERY IN THEM AT ALL TIMES !!.
 

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Discussion Starter #68
why does running with a bad battery/no battery kill the stators? and how would i check the reg/rec to see if it's the cause?
 

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Discussion Starter #69
I forgot to mention, my headlights were blown out when I first got it, so I'm thinking that the reg/rec blew them out because the quad also had a not so great battery on it....
 

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why does running with a bad battery/no battery kill the stators? and how would i check the reg/rec to see if it's the cause?
simple: if there is no place for the stator to send voltage to ?, then the stator will always think the battery ( in this case..there is none ! ) needs charging ?, in other words, the stator will '' cook '' itself trying to charge the battery thats not there !!!. same thing goes for the reg/rec, if this part fails ?, then the stator can't get its AC voltage converted to DC voltage to go back in the battery, and run the electronics on the atv, have I lost you yet ??..lol.
 

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The battery completes the charging circuit AND the battery is the load for the charging circuit. The battery is also a natural filter capacitor. Without a battery the circuit is incomplete... an open loop, having no DC load for the regulator/rectifier to reference its pullup voltage output against. So it defaults to its highest voltage output (over 16 volts of AC-laced DC usually, the DC voltage rises and gets dirtier as RPMs rise) which blows out the light bulbs. It usually fries DC CDIs and ECMs too, when the battery is taken out of the circuit and the charging voltage exceeds 16.5 volts.

In the opposite extreme, a connected battery must be in good useable condition, else excessive resistance (or a shorted cell) will either overheat (and fry) the alternator windings due to the near-short condition in the circuit, or be such high resistance that the regulator/rectifier becomes unstable due to insufficient load... behaving similar to the battery being disconnected.

So if the battery is decayed and has very high resistance the circuit becomes unstable and outputs excessive voltage. If the battery resistance is too low (shorted cells) the alternator windings and the regulator/rectifier must supply more current than they're designed for... they overheat and fry due to the overloaded condition.

Your exciter windings problem have nothing to do with the operation of the charging circuit & battery though. The exciter windings are completely separate and independent from the alternator. The exciter provides its AC voltage & small amount of current for the AC-CDI and ignition coil, only.

One leg of the exciter winding must be grounded and the other leg goes to the CDI, then to the ignition coil. If neither of your exciter coil legs are grounded look for a broken wire where that leg grounds through an exciter mounting bolt. Also look for an internally broken wire where the harness passes through the rubber boot in the cover. It may be grounded on one leg but open on the other... so check them both.

The reasons why exciter coils fry...? Everything has a very limited lifetime in universe, but other common reasons include improperly matched ignition coil and/or improperly matched CDI. In those cases its because some moron put china knockoff parts on it, rather than buy the correctly matched parts. Again, resistance is the culprit. China crap comes with insufficient resistance, so the exciter coil overheats and fries due to the near-shorted load condition that china garbage taxes them with.

See attachments.
 

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I forgot to answer your question about the peak voltage produced by the pulse generator. The FSM states the same minimum spec (0.7 volts) for most models built since the mid 1980s, but makes no mention of a maximum voltage. The reason for that is because the voltage output of the pulse generator increases as RPMs increase. Output voltage increases as the airgap between the flywheel puck and pulse coil pole decreases too. So the airgap is an important factor on some other brands of motors that have an adjustable airgap. Honda ATVs are not adjustable.

So there is no ceiling voltage... but .7 volts minimum is required to trigger the CDI to unload its stored energy (produced by the exciter winding) into the ignition coil. The minimum .7 volts peak is the only spec to be concerned about at ~450 cranking RPMs.
 

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Discussion Starter #73
You people are Gods of small engines. I just learned a whole lot. So to summarize, because I have a brand new battery (it's an AGM btw), i shouldn't be worried about something happening again to the stator? And the headlights... what about them? Did they blow from a bad reg/rec? or was it related to the stator failing?

Thanks guys.
 

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Discussion Starter #74
oh, forgot to mention, i'm ordering parts tonight and I'm wondering if I need to throw a new reg/rec in there just to be safe so it doesn't blow things up again
 

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We don't know why the headlights burned out for sure. I didn't even realize that you had a previous charging system problem... I thought we were working on the ignition... or was that mentioned in the earlier stages of this thread? If so, I forgot. :-(

Since the headlights got blown out though, replacing the regulator/rectifier now might be a very wise decision. If I were working on it... I would replace it.
 

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And no, your alternator and exciter coil should not ever burn out as long as neither of them are ever allowed to short or become open circuits. Maintain the battery and keep the terminals clean and tight. Dielectric grease them to keep oxygen off of them and prevent corrosion. Keep frame and motor grounds clean, rust-free and tight. And pack each harness connector on the bike with dielectric grease to seal & prevent water and oxygen from ever entering those connectors. Route the harnesses properly and secure them (routing info/photos are found near the front of the FSM) so they don't ever become damaged. Don't ever cut or splice the wiring unless you intend to do it right, by permanently soldering and sealing your connection 100%. A little effort and common sense pays big dividends on Hondas. Maintenance rules.

Keep us posted... we'll be looking for some more of your shared pics... :)
 

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Discussion Starter #77
I looked at the stator more up close and personal and tested all the connections on it. I tested to see if there was continuity between one end of the exciter winding, and the other, right where the copper wire is soldered onto its leg. It was open. Which means that there is an open circuit in the exciter wire somewhere, right? I checked every other possible connection to it, and it was all open. The alternator winding had connection though. My theory on what happened was that the bad battery caused the reg/rec to freak out, over volt the headlights blowing them up, then causing strain on the stator, creating heat and casing the thin wires on the exciter coil to break. Is this possible? What caused the exciter to open circuit?

I'm going to replace the reg/rec, and the stator. But I wan't to know if there is something that I need to do to make sure this does not happen again.

Thanks for all the info.
 

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You're probably right about the bad battery chain reactions, thats already a well known outcome, but the alternator could not ruin the exciter windings in most cases. The exciter more likely died on its own... stuff happens, ya may as well accept that, replace it and move on.
 

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Discussion Starter #79
You make a good point. I noticed this discoloration on the pulse coil. It's only on the top surface, not the sides of the pole. Does this mean it's a bad coil, or going bad? Also, I found lots of graphite powder and some weird brittle metal piece inside the starter, and it doesn't show up in the FSM. It looks like graphite, but it's a lot harder than graphite. So i'm wondering whats up with that. Should I replace the brushes? Haven't measured them yet. Also, how important are the shims inside the starter. I don't have all the ones that show up on the FSM parts breakdown, but it seemed fine before... but idk.

See attached pics.

Thanks!
 

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Discussion Starter #80
Update: figured out what that weird piece was. Seems to be a support thing for the positive connector nut. It probably broke when I was trying to get it off. I had a hard time with it.
 
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