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Discussion Starter #1
So, out of the blue, my '94 Vulcan's temperature guage starts to climb. Now, I've had my share of issues with this bike, all expensive, of course, but this is a new one. We limp home as she's scraping the bottom of the red, not overheating but not far from it.

When I first bought the bike, it seemed to have a coolant leak, but the guy at the shop tightened something and it seemed to be fine. So, remembering this, I top off my coolant, hoping that's it. It's impossible to tell my fluid levels from the dark, murky, weatherbeaten white plastic windows I am supposed to read.

Anyway, I ride to work this morning-- not as bad, but still at least 3/4 in the hot zone! I get worried after work when she sounds different and seems sluggish to catch on, I'm convinced I'm going to seize the engine, so I take a chance and dump a quart of oil in. I started slowly, with a flashight, in the afternoon sun, trying to read that gross little window where the oil is either HIGH or LOW, but I can't see a damned thing. I know the oil was changed when I got the stator replaced about 7-8 weeks ago, so it isn't running with the factory 10w-40 from 1994.

The bottom of the bike looks like it's been to an orgy-- all grimy and oily, and near the front wheel, next to what I believe from the manual to be an oil line, slimmer and more tied down, is a black hose, coming from somewhere inside the bike, just loose and flappy as can be. I don't know where it comes from, and I've been poring over the manual for the last couple of hourse trying to figure it out without taking the bike apart (have to get to work in the morning somehow...)

Anyway, I get home, one eye constantly on the temp gauge, and it sits more or less happily at the halfway, normal running mark, until the very end of my ride (about 20 miles) when it creeps up a little high, close to the 3/4 mark.

On a side note, I get terrible gas mileage-- average around 30 mpg, probably because I go 70+ on the highway for about 15 miles to and form work each day, about 5 miles on normal streets, and I weigh about 230. Even so, it seems... uneconomical.

My questions are:
1) What is this hose?! Where does it plug in?! I didn't see anything within easy sight/reach of where it seems like it should go

2) Is it the cause of my oily bottom? The manual thinks there is a mechanical gasket leak, which is why the channels on the south end are wet

3) Is it why I am overheating all of the sudden? Could that be something else entirely?

4) Why do I continue to pour money into this bike, and have such a weird emotional attachment to it?!?!?! :loser1: She has a name and we have conversations. I know when she's having fun, or having a bad day. I know this is impossible, but I swear it seems to make sense when we are riding together...
 

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2000 VN 750 Senior Member
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That small tube/hose hanging down in the front just may be your radiator overflow tube. The tube should let any overflow exit below the motor and get blown down onto the roadway rather than being sent back onto the motor. If it is disconnected and your system starts to overflow from excessive heat the spray of coolant will coat your motor and pickup every bit of grease, oil and road grim making a mess towards the rear of the motor. Check to see if the tube is just that and reconnect. It should connect if my memory is correct just below the radiator fill cap under the right side neck cover. Your coolant system may also need a good flushing to get it back to its proper operating range. There is a good step by step procedure with pictures here if you do a search on the subject. If you are at all unsure when the last time was that your system was flushed and cleaned I would suggest that now it the time to do it. It is also a good time to clean up the motor so the natural cooling can help the system without all the crude from the road covering it.

This is not an expert opinion by any means but based on some experience may just solve your present issues. Besides a coolant flushing and checking for overflow tube connections can't hurt while if it corrects your problem will save possible shop down time and high costs. Good luck.
 

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Check your engine oil for gas...that will kill fuel milage and make the bike run hot...I know, because I been there...was due to a sticking float....can happen in a heartbeat too...if your crank looks overfull, drain the oil put some in a teaspoon and see if it will light, and smell it...you'll smell gas...
 

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Sounds like you are getting close to frying an engine. When checking the oil, do it with the bike on the center stand. You said NO oil was showing in the glass, added a quart. Did it bring the oil up to the top in the glass with the bike on the center stand? Low oil will cause excessive engine heat, and cook the internal engine parts. Never limp a bike home unless you plan on parting it out.:BLAM:
 

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Chasin' the blacktop
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Ok, First off the black floppy hose is probably just your gas tank vent hose. At this point leave it alone.

If you have a slow coolant leak just refilling the coolant reservoir won't preform an immediate fix. This is because the coolant reservoir can only feed water into your system after the engine has run long enough to warm up and then cools down. As the engine cools down it will suck some additional coolant in but you may still have some trapped air in the system. After several cycles your cooling engine may or may not suck in enough additional coolant to refill the system.

Your best bet is to remove your gas tank and top off the radiator through the fill cap. You will then want to open the bleed vent bolt on top of the thermostat to allow any trapped air out. Then check to make sure that the coolant reservoir is full.

Ready to ride. make that a test ride. I realize your view window on the coolant reservoir is cloudy but keep an eye on it. The level may change as the engine warms and cools but you want to see if the level generally drops.
If it drops slowly over a month you've got a minor leak somewhere.
If it drops within a few days you need to get serious about finding the leak.
 

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Chasin' the blacktop
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and yea, 30 mpg does seem a little low. What color are your plugs?
 

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Black hose flopping about = Long Dong Silver....lol....sorry, couldnt resist...
 

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Discussion Starter #8
Hi, first of all, thank you all for your contributions and ideas. I'm about to go spend my morning trying some of them out, starting with the gas in the oil teaspoon trick.

I got the bike recently, replaced the stator, battery, oil change, and according to the mechanic, he did everything one is supposed to do for the 14K service except the carbs. The previous owner gave me the old airboxes, which leads me to believe the ones on the bike are new(ish).

The plugs are sparkly new NGK's iridiums, which solved a lot of my reluctant starting problems :) I did notice that 2 of the old plugs were pretty runny with oil when I replaced them, and had developed some rust.

The temperature problem has not resurfaced whatsoever since; it occurred after a day of hard riding-- fast (85mph avg), about 1 hour steadily. Thinking that a slow leak dumped out a lot of coolant, and that's what the main problem was.

Again, though, I'm going to go clean things up a bit and look into this air bleeding procedure with the manual.

Thanks!
 

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Hello all im new and i have some questions need some help i have a 93 VN750 bougjt a few years ago long story short my petcock failed on the way to work on the freeway i had someone help me with my bike so this person removes carbs and air intake system and cooling system then gives up.......i had to take my bike back home and set up in my second dining room and reassembled. It i installed new petcock ,fuel float,carb boots and solenoid.

On the carbs you have two ports left and right i use left port #1 for my fuel vac connected to petcock and #2 i capped off i have both fuel lines connected but heres my problem whats the middle hose go to ?? It comes from a t in middle of carbs
Bike starts with some throttle action it does not fire up immediately. Ad when i give it throttle it will bog up to 4000 and kinda die need help please
 

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Old Truck Junkie
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That is the carb vent hose. It goes to the right ear. It connects to a slot behind the ear. Or you can tuck it up under the gas tank away from direct air flow.
 

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Yer in luck Biff...quite a few members in your area...mebbe you can manage to get some hands on help...
 

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Black hose flopping about = Long Dong Silver....lol....sorry, couldnt resist...
thanks wolfie... i thought i was the ONLY one with a pornographic memory :pepper:
 
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