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Discussion Starter #1
I've recently had some problems with the switch on the bike, but think I have those mostly resolved. I was having problems that when the bike turned hard right, it would cut out and I'd have to jiggle the switch. I cleaned out and adjusted the switch, and that problem seems to have gone away. I also recently blew the main fuse, which I think was due to the switch.

Now, the bike runs great but after a 30-40 mile ride, the bike won't start off the starter. I can push start it, no problem, and the lights are all real bright. But, it seems like after a long ride the battery gets low enough that the starter won't turn over the motor. The battery is a brand new MF battery.

Could this be a problem with the "alternator"? I don't even know if this bike has one, or where it would be, or how to check if there is a problem. Its an 86 with about 25,000 miles on it. So, I imagine there can be many possible problems?

Any suggestions? If I keep having these problems, my only option may be to buy another bike. Seems like every time I fix one problem, I get another.
 

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Old Truck Junkie
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Where do you live, how much do want for it??? Just playing!!
Take the volt meter set it on 20 DC volts. While engine is running test across the negative and hot posts on the batt. rev engine up some and see if the volts go up 13.0 or so. If it does the alternator (stator0 is probably ok. Be sure to check main ground connection and main hot side connections.
 

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Old Twistie Sticks Rider
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Discussion Starter #4
One thing I was thinking, is that the problem seems to be worse when the bike is hot. If it sits for a while, it seems to start up okay. Its hard to tell if the battery is actually dead or not, or if something is causing it to start hard (seems like the starter has no juice, but the headlight and other lights are very bright).

How would I check the main ground connection and main hot side connections? And where is this rectifier? Thanks for the help, hopefully I can get it going.
 

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Discussion Starter #5
One other question, I see a lot of posts about the "RR". What does this mean, and where is it located?

I did recently blow a fuse for some mysterious reason, and am wondering if that could be related to what I'm seeing. It definitely seems worse when the bike is hot, but I'm not much of a mechanic so I don't know for sure what is happening.

I'll get a meter and try checking the battery to see if its is charging.
 

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Old Truck Junkie
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On checking the connections just check that they are clean and that the clamps on the wires are tight.
The r&r is the regulator and rectifier. It is under the battery in front of the rear tire.
From what I gather you may have a starter that needs rebuilding, new brushes, bushing and some cleaning.
 

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Discussion Starter #7
Thanks, I borrowed a good meter and looks like I have some testing to do tomorrow night. I'm confused about the temperature thing though now, since just tonight I tried to start it cold and still it wouldn't start. So, I guess the temperature doesn't make a difference.

The lights are bright, so I'm thinking the battery still has some juice. The starter just doesn't turn over. It goes like its straining, and then sometimes clicks a bunch of times. I figured it was a dead battery, since when the battery is fully charged it seems to start up okay. Its hard to say. These electrical problems are really confusing...
 

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since you mention the temp, it really DOES sound like the starter like niterider said. temperature is a major factor in a starter's incapability to crank the engine
 

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Based on what I have experienced with my bike, the battery seems to need at least 12.5 V to turn over. When I was having issues with the stator and RR, I found that all the lights were on and bright, but the engine wouldn't start unless the battery was up over 12.5 V. If I charged the battery with the tender, I could ride it for a while, until the battery got below around 12.5 VDC. I'd start with the easy stuff and work back. With the battery fully charged, if you can start it, put the meter on and check the voltage @2500 and 5000 RPM. It should be in the 13.5 to 14.5 VDC range, and should increase as the RPM's increase. If it's not, then I would run the diags on the stator and RR. I can help walk you through the testing process if you need a hand. If it is charging, then the starter may be the culprit. The thing that sticks out for me, is that the bike starts on a full charge. It sounds a lot like the way my bike behaved before I switched out my fried stator and RR.
 

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Discussion Starter #10
Thanks -- I have the bike charging now (so I can start it) and do some of the battery tests. I did notice some corrosion around the poles of the battery, which I've never seen before. I did have it on the charger overnight by accident (on 2amp charge) right before this problem started. I don't know if that could be related. The battery is brand new, though.

Are there any pics anywhere of where exactly the wires on the RR are to test? I can see the RR, but am having trouble figuring out what exactly needs to be tested.

If its the stator, the bike might be done for. It sounds like that is a tough job, and I'm not much of a mechanic. How much would a local mechanic charge for fixing that? I only payed 700 bucks for the bike, but I've put over 600 bucks into this year so far (tires, brakes, battery, tune-up). I hate to have to get rid of it, but if its going to cost me a fortune then I might put the money into a newer bike. I'd like to get this one running good at least, so I can sell it without screwing someone over.
 

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Chucklehead
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Just my $.02 ... You might check the connections at the starter solenoid. If the starter won't crank at all and you have good voltage the solenoid may not be working or connections could be corroded.
 

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Old Truck Junkie
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2 amps is the most U want to charge this batt with.
Let us know how it goes. If you need help hallor.
 

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Discussion Starter #13
Okay, just got in from the garage. The battery is still pretty dead, but I have it charging more right now. It was reading 11.8 volts with the bike off. With the bike on, it dropped to about 11.3. Reving it up, it climbed slightly, back to maybe 11.6 or so at about 5000 rpm.

I'm not sure if this is because the battery is pretty dead at the moment (just barely enough to start it), or if there is really a charging problem.

So, I checked the RR thing. What a fin pita to get at it, but removing the wiring harness helped. I tried to check the pairs of wires as such:

A B C
D E F

Checking A-D, B-E, and C-F.

With the meter on 200 ohms, it showed (with the bike off):

A-D 1.5
B-E 1.5
C-F nothing (infinite)

All of the wires read infinite against the engine block.

So, after much pain and blood loss, I managed to get the connector off of the R&R and checked it while disconnected. Checking each of the male connectors on the RR showed infinite resistance to the engine block.

Checking A,B,C,D,E on the connector (female) side showed about 2 to the engine block and 0.5 to the negative terminal of the battery. Wire F showed infinite resistance to the engine block or the negative terminal.

This makes me suspect this wire F. It is a white wire, that goes up somewhere near the battery where the wires split off towards the front of the bike and then over to the other side of the battery. I can't really tell where this wire goes, or if it could be the problem.

I was fiddling with the front wires earlier last week, because of problems with the ignition switch. I've suspected that maybe the switch was still to blame, but I'm not sure if the switch is even anywhere in the loop of charging. If its the switch again, maybe its an easier fix. I dunno.

This whole thing is starting to depress me, so any help would be most appreciated. I'm going to start drinking now, mourning the likely loss of my first motorcycle to some mysterious wiring issue. I'm still hopefully there is something I can do, or maybe I can get it fixed at the garage, but I hate to spend a fortune paying a mechanic to go on a wild goose chase.
 

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Those battery readings are low. Did you check the 3 wires from the stator?

Check all three, (with bike off) and check between all three wires. Readings should be .3-.5 ohms.

Also, (with bike off), check each wire to the engine case, you are looking to see if the wires have shorted to ground. A short to ground is a dead stator, and not uncommon.

Oh yeah, do the test on cold engine, then hot. (but not running hot-shut it off after warm up before testing)
 

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IBEW 915 Electrician
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115 Posts
Yuasa MF replacement done but...

I did the Yuasa battery replacement. Before that the idle was OK with the old battery. Now the bike runs a little rough and stalls below 2K. High revs seem OK. The stator wire connectors are good. They were replaced by the dealer for $133.00!! That was before I found out about this website. Since then I have learned the meaning of "stealership". The bike sat for weeks before I got the MF.

Bike starts OK but needs the throttle turned up when at idle. Have I described a stator symptom?
 

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Old Truck Junkie
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Have you adj your idle with the "idle adj screw"? It is a black knob on the left a bit under the fuel tank.
 

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IBEW 915 Electrician
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I did as you said and tried the adj. screw but it didn't seem to make a difference.

I have some new iridium plugs to to install but no one in town, from Home Depot to Advanced Auto, has an 18mm spark plug socket. The 18mm spark plug socket is sold out in this town.


HD wants to sell you a complete deep socket set with 1/2" drive for $25 and their torque wrench is overpriced and out of torque range for the plug. Advance auto has no torque wrenchs in stock. They must be ordered on line. More and more I am walking out of these chain stores empty handed. I don't even want to talk about the K-saki dealer.
 

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Spaceboy,
Any progress after the battery recharge and hangover recovery??
There are several possible causes to your problem. Dirty connections will not allow the battery to charge properly as too much current will be lost because of the added resistance from the dirty connections. You may want to insure that the ground wire to the frame is nice and clean and that the black/yellow wire on the same lead is connected. The positive lead can also get dirty, clean that as well.
You should also check the connections at the starter solenoid. Dirty connections there will not allow enough current to pass and turn your starter motor. Dirty connections are the bane of this bike.
As far as your resistance readings for your R/R, something is wrong here. I have included the troubleshooting matrix from a manual here so you can see what your resistance readings should be from pin to pin. If you try again and get similar results from your last test, it may be your R/R. I'd also recheck the stator readings and do an AC voltage test of the stator output to ensure that the stator is functioning normally. A bad stator can and will take out the R/R.
 

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Discussion Starter #19
Thanks -- how do you test the stator output? I'm still having trouble with this, so much so that I actually bought a new bike. BUT, I plan to fix this problem and hope to fix up the old Vulcan and ride it once again.

I just need to narrow down the problem to the stator or the RR. I'm unclear on how exactly to do that.
 
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