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Discussion Starter #1
Hey all!

I have finally after several months working with the previous owner acquired my machine. Rode her 35+ some-odd miles home over the mountains from his shop. Much work had to be done before that ride was possible, much rebuilt in the shop, but that's another story.

On the way back the coolant reservoir overflowed after much riding and finally meeting city traffic. With only about 8 miles of inner-city rush hour traffic to go i endeavored on until finally she died and battery wouldn't kick her over. Pulled over and we both cooled off for about 20 minutes, started her back up, head home, and took a look at her this morning. Battery problem was obvious, the shop has a "genius" mechanic. One of the cells was bone dry, another was about half way up the wall, the others were fine. Replaced the battery with an ETX15L AGM. With that problem solved, i refilled the coolant, restarted, let her get warm, shut her down and she sucked up a full reservoir of coolant. Refilled, that's all fine now too.

Talking to my friend, the shop owner on the phone, he was asking about the fan. And sure enough, as far as i know the fan hasn't yet turned. So, i have read all of the various troubleshooting articles about fans in this section of the forums, and it will be tomorrow before there is enough light to ground the fan-switch, etc. I combed through the maintenance manual, etc. as well and i still have one question i simply cannot find the answer...

What is the temperature ( on gauge or otherwise ) where the fan should turn itself on? Should it just turn on after the bike is more or less idled warm? Does it turn on only when it's sensing extreme heat? I am tempted to just go ahead and put in a ground toggle to bypass the switch as several have suggested ( as well as the shop owner ) but since this is my first VN750, i still haven't a clue when i would turn the switch on myself. If it runs constantly on a switch while the engine is turning, is that going to pull down the electrical system... lose battery life? Is the fan loud enough to hear while out in typical traffic? On the flip side of the coin is a very wise anecdote: if it ain't broke fix something else, like my ears. :doh:

Other than that, she simply howls... she has a lot of minor problems, but most of them are cosmetic or broken items and she needs TLC. So this fan question is basically the only thing standing between riding on "reliable" and "worry". Know what i mean? :)
 

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on my bike, the fan turns on at just about 1/2 way on gauge.. maybe a little higher.. it does not run full time (when ign is on). I cant really hear my fan when sitting still and it turns on, but I can sometimes feel an increase in warm air around the legs (I live in the south, and usually have shorts on..)

the ground to bypass the temp switch in the bottom left of the radiator is a testing method in my opinion.. I think you would be taxing the charging system if you left it running all the time. if you ground the wire and the fan runs, then everything else in the circuit is working properly and you just need the temp switch.
 

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Same here, I don't always hear the fan, but can feel the hot air when it kicks on about midpoint of the gauge. Sometimes at a stop I'll just lean over and look at the blades.

When my fan quit, the spade terminals in the Junction Box plug were loose. Just had to pull them out of the plug, then pinch them with pliers to fit tight. I grounded the fan switch wire then wiggled the wires at the JB plug to find the loose spade. It's one of the blue wires, I think.
 

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Discussion Starter #4
thanks and update

Thank you both for the info. Pulled the wire/socket off the fan switch, used some #2 high grade toilet tissue to sop up the oil glut around the switch's tab and inside the socket using a J.C. Penny stock number #NSN 7510-00-958-0743 paper clip which fortunately for me, somebody had left nearby in the weeds of the parking lot. They must have been psychic, i guess.

With the wire disconnected from the switch, i shoved a flat end screw driver into the socket and used the neck of the same to ground the JB relay's coil circuit to a nut on the frame. The fan started to whir which made me smile.

So now i am thinking about a mod. I know eventually someday that switch might just fail ( presuming it's working now ) and leave the fan running all night. And i like the idea of a switch on the handle bars to avoid that situation. I also like the idea that the engineers designed it to be automatic so i am thinking about a mod that does the best of both worlds. An LED could be run in series with the coil side of the JB relay to light up whenever the fan is supposed to be on. A switch could be run in series as well and simply turned on when running, off when parked, and instead of being an override, being an enable/disable switch for the control side of that system.

I took her for a short ride today but the temperature stayed below the halfway mark so really don't know yet if the temperature switch is actually working. There is really no reason to doubt that switch though since it was out of circuit due to all the oil in that connector on the way home the other day. There is equally no reason to believe that i have a good connection there either yet. So for now, i am happy at least a "culprit" was found and can monitor the situation with an informed perspective.

Thanks again and if you have any ideas about that mod, let me know. I'm going to hunt around for LED toggles that can get that mod job done.

:rockon:
 

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If you let it idle long enough, the fan should kick on.

If the fan switch happens to be at fault, an LED on the bars would never light. The switch is what activates the JB relay.
 

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one thing to remember, if needed, the fan will run for a short time (usually less than 1 - 2 minutes, often only a few seconds) on shutdown if the coolant is hot enough.. Mine does this fairly often during the summer after riding.
 

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Discussion Starter #7
If you let it idle long enough, the fan should kick on.

If the fan switch happens to be at fault, an LED on the bars would never light. The switch is what activates the JB relay.
Exactly. So the idea is that while riding, a quick check of temp-gauge and the LED should tell the story. If the gauge is leaning to the right and the LED is on, everything is fine ( at least on the sense/control side ). It won't ever really mean the fan is actually turning, just take the fun out of troubleshooting with a screwdriver while on the highway. :nerd:
 

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Discussion Starter #8
one thing to remember, if needed, the fan will run for a short time (usually less than 1 - 2 minutes, often only a few seconds) on shutdown if the coolant is hot enough.. Mine does this fairly often during the summer after riding.
I get the drift of that as well as what Spock was saying.. i suppose if it's really worth doing a "full" mod, what would do the trick is two switches and an LED, and instead of the LED watching the control side, since it's on a relay anyhow, it should be watching the fan/load side. What's the difference if the relay has juice but it's stuck or there's a bad connect to the fan some place? The LED should only light up if the fan is actually turning. One toggle would allow interruption of the control side of the relay, and the other toggle would parallel the fan-switch to override it. Simple circuit. Two switches, one in series, the other in parallel to either defeat or enforce that relay either way.

The LED on the load side has quite a few options, but without getting too difficult, something between an 8k to 15k resistor in series with it to ground would monitor if juice is "supposed" to be turning the fan, rather than if the fan is actually turning. They used to call things like that "idiot" lamps where i come from.

To monitor if the fan is "actually" turning with an LED would properly require a transistor in series with it on the ground side. That's where it gets to be a bit more than its worth bothering since as mentioned, just looking at the fan tells the story there. The idiot lamp is only there to warn one to pull over and see for themselves. if the lamp is on and the gauge is leaning to the right, then the bike is doing the best it can to cool down.
 

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If you were riding in cool weather, the fan may never kick on, and it could take quite a while just to reach normal temp, if it ever does. 35mph in the summer is enough to cool mine without the fan.

Don't know if you do ebay, but there are fan switches on there reasonably priced, just have to watch for the deals. $30 is pretty high in my opinion.

A fully functioning charging system drops about 1 to 1.5v when the fan is running. So running the fan more than needed could run into trouble on a long ride.

You can test the fan sw. with an ohm meter and a pan of boiling water.
 

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Discussion Starter #10
If you were riding in cool weather, the fan may never kick on, and it could take quite a while just to reach normal temp, if it ever does. 35mph in the summer is enough to cool mine without the fan.

Don't know if you do ebay, but there are fan switches on there reasonably priced, just have to watch for the deals. $30 is pretty high in my opinion.

A fully functioning charging system drops about 1 to 1.5v when the fan is running. So running the fan more than needed could run into trouble on a long ride.

You can test the fan sw. with an ohm meter and a pan of boiling water.

I'm so way not a tuff guy, but my garage has a palm tree that blocks the sun sometimes and has a asphalt floor if you get my drift. I think if i had a meter, the best test for that switch would simply be to idle the bike instead of pulling it out and having to refill the radiator.

Since it's only a continuity test, i might just do that tomorrow just to make a meter. Too bad Radio Shack went out of business though. But on the bright side, there are enough worn out appliances tossed on the street in this part of town that i can easily find an LED. Somebody tossed out a nice Magnavox flat screen recently that i am going to rip apart for parts. Simple continuity tester is just two leads one on that tab, one on ground, a 1k resistor, an LED and a AA battery ( or AAA or whatever works ). The switch should eventually close somewhere around the time the temp gauge starts leaning to the right.

I am SURE, however, that the oil that built up in that connector was the problem since i know where the oil came from and when. I also know that the mechanic at the shop may have ridden the bike around the block or something but certainly never got it hot enough to need the fan.... then on the other hand, since he was charging batteries that had 1.5 cells completely dry, what's the difference how hot it got when he was checking out the bike? ( shruggs )

What *happened* about a month ago, the first day i finally had her paid for and pink slip in the mail, etc... was on the way home, she only lasted about 3 miles down the road and then had what i will call a blowout. I had just begun to shift into third, clutch was in, and suddenly WWWwwwRRRRRRRRIIIIIIIIIII..... she was at max RPM which sort of freaked me out for a sec, i had to hit the kill switch, to which she replied with one seriously enormous backfire, oil splattered all over the place from several sources, and gratuitous amounts of white smoke as various fluids boiled off her fins, etc. etc.. My only choice, that far away, was to have her taken back to that shop. The OWNER of the shop, is a very cool guy and hauled it back for no charge, and thus began a month of them finally finding out that the previous owner of the bike had rebuilt the carb using his own home-made parts. They replaced the head gaskets which blew, seals, several hoses, all sorts of various things, and this is the part of the story i sort of glossed on over at the top of this thread. So... basically, i am about 99% sure that connection was simply fouled and seriously, this morning after pulling it off, it was sopping wet with oil inside and on the tab.
 

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Discussion Starter #11
Don't know if you do ebay, but there are fan switches on there reasonably priced, just have to watch for the deals. $30 is pretty high in my opinion.
A105SYZB: SPDT Mini Toggle Switch: Alcoswitch/Tyco Electronics

That should do the job, brand new for about 2 bucks. Just because we started this thread, i am going to go through with this as a project just for kicks. I am thinking about how to mount the parts in a kewl way on the handle bars. Also, i do eventually need to have these handle bars replaced since the bike was ( pretty obviously ) in a wreck of some kind and they are slightly twisted. The left grip is ~about~ a full inch forward of the right when the bike is "straight". It's not a lot, but it's certainly enough to want it replaced.

Is there any reason why wires are *not* run through the hollow of the handle bars? Just curious if drilling a couple holes here or there is some sort of frowned upon bad idea.

For a mount i am thinking about a sheet of chrome plated tube with a slot cut out long ways. using that as the housing for the switches and LEDs. Then attaching it to the handle bars with hose clamps that are hidden inside the sheathe. a couple more pair of slots could be cut into the tube like belt loops to run the belt of the clamps through and small access holes to allow a screw driver to turn them tight on the underside.

I repaired the missing lock on the lock box today with a post-box lock and a large washer. That cost $0 and shipping was free.

:grin2:
 

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Lockbox mod photos: ( out of order )


First two are the finished mod, the lock installed is a common post-office box lock with a washer behind its face to give it a front face ( i.e. rather than just the bare plastic ). Had to cut a wee bit of plastic to allow the tongue of the lock into the slot better on one side. The third picture shows the original condition, a big hole and a piece of duct tape the previous owner had been using.

Total parts: ( used post box lock, and one washer )
Tools: knife, screw driver, pair of pliers.
 

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reply and update.

where are you located?? that sounds like my 'garage' except I have concrete...
Central Los Angeles. And for now I have the parking lot out back and a friend that shares tools. I was hoping to get a cheap socket set at the store today, but see the update below:

Update part: The fan switch has now been formally tested. I took a ride today all of 3 miles in 86F temperature this morning and lots of stop lights. She warmed up nearly to the red line on the temp gauge. When i finally got where i was going, i got off the bike with it running and tried to see if the fan was spinning. With the bike running, it's just too loud for me to hear even on one knee trying to see it from the left side looking straight at it. I couldn't make out a blade sitting still on the bottom, but i also couldn't really say it was turning either... just too hard to see. BUT, i turned the bike off and she turned the fan on all by her self, and at that point i was thinking.... hmmm... maybe the switch is just getting old and the temperature needs to be "serious" high. I really don't know, but it at least closes its circuit which led to another problem i thought i had fixed....

I had to get some business done there, and when i came back out, she had sit for all of maybe 20 minutes, tops... she wouldn't crank. The battery had no juice. This is a BRAND NEW BATTERY AGM that i bought yesterday ETX15L. I got a jump about an hour later and cranked up turned over first try. Rode her home with a manual slightly high idle making sure she didn't die at a stop light. So now i am perplexed about the battery. It is evidently not charging well, or not charging well because of the heat, or being suckered down due to the fan, or s o m e t h i n g. So i am going to charge it up here at home base ( friend has a charger ) and slap a fast make-do switch on the frame to bypass the fan switch altogether. Then i'll take another ride this afternoon and turn the fan on manually when she is about "half" hot. I'll do a full 6 miles ( double the previous ), bring her home and try and start her after she sits 20 minutes like before and see what happens.
 

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FREEBIRDS MC CENTRAL NY
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Test your voltage while running
 

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hey Doc

Test your voltage while running
You read my mind. But i read all your other posts here too. Go figure that. Tomorrow's mission is to get that socket set and a cheap multimeter.

Have to take the bus. :frown2:
 

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Should be about 12.8 at idle and jump up to about 14 at 3000 rpms
 

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Should be about 12.8 at idle and jump up to about 14 at 3000 rpms
Sitting here now waiting for the "battery charger" to charge, so thought i'd login. Still waiting to kick it over.

The only thing i've seen my tach do so far is sort of bounce around between 0 and 2 regardless of how often the pistons are firing. Not sure how to pull it, but that might be something to get done today as well.

She needs lots of TLC ... Tending Loose Connectors. Found one sort of busted that runs two wires up under the fuel tank. I am thinking about just getting a set of new connectors for all around the entire bike and just re-doing every last one. It would solve a lot of time and it would get the "rebuilding" job done right. Most of them are dried up as far as plastic life goes.

:nerd:
 

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Should be about 12.8 at idle and jump up to about 14 at 3000 rpms
Finally got her running. She appears to like a backfire when starting up now. But put the meter across the battery while she was idling fast about 2k and it was already at 14 and giving her a rev had no effect at all, ( which it shouldn't if my meter's 14 is her 14 ). From that fast idle i slowly let down the choke as she warmed up and eventually she was doing i would guess maybe 300 rpm or less, just earballing it. About 3 to 5 pops per second using "one thousand and one". This meter is manual and on a 50V scale, hard to see much diff between 14 and 12.8, but it was noticeable. She was off just a half meter mark less than the line.

For whatever reason, the fuel gauge was now stuck on FULL tank ( and i know it's only half full ). I took her for a ride and that fixed itself.

I have decided to pull out the entire section including the battery case right according to the manual. Wash it all down, crimp/replace every connector in that area. There is enough white powder on enough terminals that it's obviously had a major battery spill or two, or maybe they parked it under a dock near the beach for a year. In any case, i've fixed enough TV's in my life to know better than to chase "the one problem". Big waste of time, that. I may as well sand and paint the case as well, and pull off the tach for a little TLC.

Damned fans. :grin2:
 

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If your rpm guess is even close, it's about 700 rpm too low. 1000-1100 rpm is spec, I think.

14v may be as good as you'll get on a stock system, which is fine. You might look at the Two Wire Mod in case it's having brownouts.

If I open the throttle at all on a start, I usually get a pop. But your description sounds worse than that. It was popping fast while idling? Makes me think of sticky valves, but the idle sounds like it's way too low.
 
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