Electrical Connections to Check - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 2 (permalink) Old 01-16-2006, 09:58 PM Thread Starter
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Electrical Connections to Check

1. Cory, there are a couple of other things to check before suspecting the alternator, which is definitely still working at least partially. Some of the things to look at (if you haven't already):

Check the bullet connectors in the alternator leads behind the engine. They should be tight and uncorroded. They've been known to be a source of problems. If they are a bit loose one might be creating a poor connection when warm. Could be a reason for the higher charge voltage with a cold engine.

Check the ground connection and cable on the battery. Could you have any corrosion in the J box? One of the yellow leads from the alternator also goes there as well as the R/R. It's for the relay that keeps the headlight off until the bike starts. It may possibly be grounded. Battery acid getting into the J box is a known problem. A partial (or complete) ground here could be a problem. There may be other things to check, too, but that's what I can think of right now. MokiMan

2. Also check the positive battery cables/connections on the battery posts, of course, then follow the heavy red cable from the battery over to the starter solenoid (right side cover). Make sure that's clean and tight. There's a red/white (I think) wire coming from there with a bullet connector make sure it's clean and tight too. Then clean all j box connectors. Watch for a follow up post about some changes I made to the r/r wiring. WV Ken

3. Have you checked out the fault finding diagram on Electrex's web site? It has an extremely useful step by step flow chart. See it at:


Q: While riding I lost my headlight, Tail & Brake lights, Tach, Instrument lights.While the kick stand is down I can drive off the bike doesn't shut down. The charging system is working. I replaced the Junction box and the regulator. I'm thinking that maybe it might be the Igniter. Has anyone had a problem like this.
A: Electrical problem Usually if the igniter goes.. you don't! I am assuming that you replaced the junction box because of blown fuses? tail / brake lights and the speedo /tach lights are all connected to one fuse. Casuse for this counld be a short. Check all the wires to you light staring at the rear for possible wear or pinches in the insulation. I recently had no rear lights or speedo/tach lights due to a short in my sidecar taillight. replacing the fuse gave me lights ubtil I hit the right bump. Also clean the plunger on the kickstand switch to make sure it is moving freely and the tab on the kickstand dpresses it when it is down. In the files section there are a couple of tests you can do for the R/R and stator Files > Electrical and Lighting > RR & Stator Keep us posted. Dianna

A: I'd start checking the condition of your wires/plugs around the frame head, or inside the headlight housing. I'd also focus attention on all the black and yellow stripe'd wires. You may find one disconnected or cut. These wires provide a ground for many switches and devices around the bike. Make sure you re-route the wires from interfering with the movement of the forks, left and right. Good Luck Lance

While reading that article from gYpSy that Bulldog mentioned, I saw this at the bottom of the page which I had not seen recommended in here yet when discussing shorts. It sounds like a good techique to use and we should recommend it when people are having battery issues..as well as the grounding technique that is also mentioned. RB

gYpSy's web site is at: http://ourworld.cs.com/Moonmist115/vulcanwebsite.html

excerpt from:


Electrical shorts are usually due to a pinched wire where the crushed insulation of a "hot" (positive) lead is touching the metal frame components and draining off the battery, even when the bike is turned off. It's not enough drain-off to overheat and burn the fuse out, though...Typical crushed-wire points are: under the seat, under the gastank and behind the headlight. You can test for battery drain, even with the bike not running. Hook up a multimeter (analog or digital) that has at least 5 amps of DC Current-measuring capability (most do). Be sure to hook-up the leads to the multimeter properly--most Analog (older type) Multimeters require you to move the red lead to a special jack in the panel. Then with the battery NEGATIVE lead disconnected, touch the red probe of the multimeter to the battery harness wire and the black lead of the multimeter probe to the negative lead of the battery ("in series")--battery still disconnected from the harness--. IF you have any measurement of current at all needle moves, either something has been left turned on or you have an electrical short. Finding it is a patient process of elimination. Try pulling one fuse at a time from the junction box or wherever else you have installed aftermarket fuses and watch the meter to see if the current drops to zero. If that doesn't reveal the problem circuit, try pulling each wiring harness *connector* from components around the bike--start at junction box, then ignition module, etc. Sooner or later you'll discover what cicuit/where the short is and then you can focus on that area of the electrical system.

Last edited by Vulcan Verses; 01-16-2006 at 10:01 PM.
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post #2 of 2 (permalink) Old 01-16-2006, 10:01 PM Thread Starter
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Engine cutting out & headlight problems

Actually, my bike was having problems a while back... once every 3 or 4 weeks I'd be riding it (it's my daily commuter) and it would die. I'd be going 30mph or so... maybe 50mph another time, and it would start bogging down and acting like it wasn't getting gas, and it'd die. It wouldn't start for an hour or so. Sometimes when I kept trying it would backfire, other times it might start up but be missing on a cylinder. I got rid of it (knock on wood). I was already to have a new igniter and ignition coils put in... but a buddy and I decided to just take a can of radio shack tuner cleaner, and some stiff bristled small brushes of the type used to clean electronic stuff... and clean all the connectors. We just opened up every connector we could easily get at with the side panels off, sprayed in some contact cleaner, brushed real good with the little brushes, and hit it with contact cleaner another time or two to flush away any oxidation that got knocked loose. I'll be damned... the thing started right up and acted like a whole new bike. No kidding. It even seemed to have more POWER... seriously. Connections in connectors can get oxidized, and even look okay and still be a little resistive. I'm not much of a mechanic, but I am an electronics tech. each of those spots that are going resistive will drop your voltage a bit, and dissipate power as heat. Clean everything up with a brush and some tuner cleaner... and it seems like it can make a real difference. My bike has behaved well since then. I'm actually wondering if this isn't part of the cause of some of our stator and R/R woes... since when this stuff gets oxidized or dirty and resistive... everything electrical has to work harder? Just a thought - a mechanic I am definitely not. Get the TV tuner cleaner at Radio shack. It's about 7 or 8 bucks a can, and comes with the handy red straw for spraying. It's well worth it, and won't dissolve any plastics like some electronic cleaners will. It's safe to use. Also, if you have a control on a stereo or something at home that's gotten intolerably scratchy... give that a squirt too just for kicks. Scott

I also hit those connections with dielectric grease to help keep those contacts clean longer. Dianna
Reminder - exercise some caution with dielectric grease. This stuff itself doesn't conduct eletricity (you can test that with a multimeter). Product directions usually say to maintain metal to metal contact. So putting it between delicate connections that aren't tight could stop current flow. If the connection is tightened down it pushes the grease out and makes a coating to seal around the outside against dust and water, etc. In a situation like Bill described in his post, with a small component where small springs push flat plates together there may not always be enough force to make "metal to metal contact", leading to intermittent problems. I've heard of people putting PlastiDip (rubber tool handle coating) on the outside of connections after they're put back together to seal them (never tried it myself - yet). "Limey"
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