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Discussion Starter #1 (Edited)
Hi Everyone,

I have been lurking for a couple of months and I really appreciate all of the information that I have culled from your lively posts. There are some real characters here! I chose to make my introduction in the Electrical forum because that's where I have spent most of my time.

I have an '03 vn750 and have already replaced the stator and the R/R and relocated it as suggested here. It seems to be charging well, except for the battery not holding a charge very long. (I replaced the battery with a Yuasa or Westco MF this summer as you guys recommend.) Last night it had to be jump started as I left from work, then stalled after idling for about 4 minutes at a red light and had to be jump started again. I have high-falutin' Amprobe DC current clamp and I when I got home I monitored the current at the battery cable. Here's what I observed (from memory, didn't write it down):

Idle - headlight OFF - (-) 3~4 Amps (current FROM battery)
Idle - headlight ON - (-) ~8 Amps
1500 rpm - headlight ON - (-) 1 Amp
2500 rpm - headlight ON - (+/-) 0 Amps
4000 rpm - headlight ON - (+) ~8 Amps

The battery was not fully charged and I did not monitor it long enough to verify that the current diminshes as the battery became fully charged. I measured about 12.2 V at idle and about 13.5 V at 4000 rpm.

All of this makes me think that the stator and R/R are working properly. I may test the raw stator output this weekend, but I suspect that the problem is with the battery. Someone said that a ruined regulator will take the battery out. I will take the battery to Autozone to be load tested this weekend.

Does anyone know what the failure mode is that kills the battery? Is it too high of voltage when the R/R control circuit stops working? Just wondering what your experience has been.

One more thing: I have about 16k on my bike and haven't checked the rear drive splines yet. Hopefully I can get to it this weekend. I have read a lot about the lack of grease and I found the front spline sorely lacking when I did the stator replacement. Maybe I will be pleasantly suprised. I'll let you know what I find.

Well, thanks for the great info.

-DC
 

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You could have ended up with a bad out of the box battery, as I've seen it happen before. It could also be some weak wiring going to your coils. Does the bike turn over good but not fire? Or does it turn over weakly? If it turns over good but doesn't fire, I'm betting on weak spark from weak wiring. If it barely turns over, even when warmed up, I'm leaning toward a bad battery.
 

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The Westco's seem to lead over the Yuasa's for bad out of the box batteries.
 

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Geek
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My Yuasa has been working fine.
 

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Your voltages at the battery should be higher. 13.5Vdc at 4K rpm is low, should be into the 14's by then.

Should not be 12.2Vdc at idle, should be closer to if not over 13Vdc.

Your battery may not be getting charged correctly with these lower voltages.

Check out the charging system fault chart here http://tinyurl.com/y99ef8.

Let us know what you find out.

Jon
 

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That's what I meant, the Yuasa's seem to have a lower failure rate. The Westco's seem to have a problem. It could just be the results from this forum but if those results are indicative of a problem, those of us in the market for a MF battery should know about it.
 

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Discussion Starter #7
Thanks for the replies.

The bike just cranks slowly and eventually won't crank (click, click, click). The battery is either not getting charged enough or has no capacity.

But wait! I just got back from Checker Auto where they tested the battery and the machine said 187 CCA; I have the Yausa YXT14AHL-BS maintanence free, CCA of 210. Only 10 percent difference, probably not the culprit. What do you guys think?

I agree with Jon, is seems that the voltages should be a little higher. BTW, I cannot access the troubleshooting link that you gave. I guess I will have to go through the whole procedure tomorrow---unloaded stator voltage, regulator output voltage, current in. Can't think of anything else to test. I'm kind of suspecting that, since (if?) the voltage is low, the stator may be partially shorted. Has anyone seen an R/R that is faulty out of the box, causing low regulated voltage? I just got mine, OEM from Ron Ayers.

Well, I'll let you know what I find. Any other ideas would be appreciated.
 

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I would check the wiring...187 CCA should be fine IMO. what is the history of your bike? has it been outside alot? connections could be corroded. as for the question about a faulty r/r out of the box...anything is possible.

hopefully those splines will look like mine when I saw them 66k miles and they look like new...not a whole lotta grease but was such a pretty site to see.
 

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darrelc5 said:
Thanks for the replies.

The bike just cranks slowly and eventually won't crank (click, click, click). The battery is either not getting charged enough or has no capacity.

But wait! I just got back from Checker Auto where they tested the battery and the machine said 187 CCA; I have the Yausa YXT14AHL-BS maintanence free, CCA of 210. Only 10 percent difference, probably not the culprit. What do you guys think?

I agree with Jon, is seems that the voltages should be a little higher. BTW, I cannot access the troubleshooting link that you gave. I guess I will have to go through the whole procedure tomorrow---unloaded stator voltage, regulator output voltage, current in. Can't think of anything else to test. I'm kind of suspecting that, since (if?) the voltage is low, the stator may be partially shorted. Has anyone seen an R/R that is faulty out of the box, causing low regulated voltage? I just got mine, OEM from Ron Ayers.

Well, I'll let you know what I find. Any other ideas would be appreciated.
The troubleshooting chart is over on the Yahoo groups site unders files, electrical, fault finding.

Definitely check all connections for corrosion. Hate to say this, but I'd suspect that stator over a new out of the box r/r.

Let us know.

Jon
 

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Also For Voltage Tests Do You Have Permanent Daytime Headlights Or Not. As uk Vn's Usualy Don't Have This And Battery Demand Is Lower?
 

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93VN750 said:
Your voltages at the battery should be higher. 13.5Vdc at 4K rpm is low, should be into the 14's by then.

Should not be 12.2Vdc at idle, should be closer to if not over 13Vdc.

Your battery may not be getting charged correctly with these lower voltages.

Check out the charging system fault chart here http://tinyurl.com/y99ef8.

Let us know what you find out.

Jon
I'm going No and Yes on this one. No, it shouldn't be 13 volts at idle. The stator doesn't produce significant voltage or amperage at idle. The bike's running off of the battery so 12.2 volts is a totally realistic value. This is why you don't want to participate in any long parades. Stick to open road crusing. I will go along with the voltage should be a bit higher at 4000 rpm though. You should test it at 2500 rpm and then again at 5000 rpm, and test it when the bike's good and hot. Stators can fail so that they test ok cold, but not hot. Checking out all of the ground connections is a REALLY good idea. One bad ground can give you all kinds of grief. Check the connections to the R/R too. Look for melting or discoloration. Make sure all the spade connectors are clean and making good connections.
 

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Discussion Starter #13
Yep, it's the stator

Uh-oh...

I tested the stator yesterday after fully warming the engine up and I found a high resistance short to ground. I used two multi-meters to compare readings; neither one registered conduction until in the 200 M-Ohm range. With the R/R disconnected, testing at the multi-pin connector:

A1-GND = 14M Ohms (meter #1), 34M Ohms (meter #2)
A2-GND = 14M Ohms (meter #1), 34M Ohms (meter #2)
A1-GND = 14M Ohms (meter #1), 34M Ohms (meter #2)

A1-A2 = 0.9 Ohms
A2-A3 = 0.9 Ohms
A1-A3 = 0.9 Ohms

At 4000 rpm:
------------
A1-A2 = 3.4 VAC!!
A2-A3 = 35 VAC
A1-A3 = 35 VAC

With the R/R connected, it never put out more than 13 VDC at 4-5000 rpm.

I drove the bike about 2 miles with no oil pressure a couple of months ago after laying it on it's side when getting off if it. Burping it at the filter fixed that, but the dry stator coils probably got cooked in one spot, which would account for the uneven output with respect to ground on the three phases. This stator should not produce any voltage wrt ground until the R/R is connected.

Does anyone have any other ideas? At this point I'm looking at another stator replacement. First one was at ~8000 miles.

I saw the picture of Jon's new stator from Mike's Motorsport and it looks pretty stout. The output leads look nice and heavy. Is this the best stator to use?

Any help is appreciated.
 

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I think ya mean Ricks Motorsport( < link) That's where I'm going to be ordering mine from. I've heard of more than a couple people who went with the Electrex and it didn't last too long.

Did you go with a stock stator the first time?
 

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Discussion Starter #15
hyperbuzzin said:
I think ya mean Ricks Motorsport( < link) That's where I'm going to be ordering mine from. I've heard of more than a couple people who went with the Electrex and it didn't last too long.

Did you go with a stock stator the first time?
Uhhh, yeah, I mean Rick's Motorsport. Thank you.

My first stator was whatever the guy at the local shop ordered for me, but I'm sure it wasn't OEM. I installed it, but don't remember what brand it was. I was not impressed with the output leads or the thin bullet connectors so I soldered mine into the harness leads. I'm about to order one from Rick's unless someone tells me otherwise.
 

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My second one is a Rick's. Almost 3,000 miles later, going good. Knock on wood!
 

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Ron Ayers OEM lists for $260. Rick's lists for $140 and is better built. No brainer. Rick's for me when the time comes.
 
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