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Discussion Starter · #1 ·
I'm back again with an update. I still don't see >13V when riding. I installed the MOSFET R/R (wow, very straightforward install! it went very well) and also performed the blue wire mod (wow...even more of a straightforward mod). I finished an hour long ride today and my battery reads 12.54V. That's over 90% charge, not bad!

However...

As soon as I flip the key to on (engine is still off), this voltage drops to 12.12V. Could it be an issue with the Junction Box? Could it be my onboard voltage meter attached to the turn signal wiring causing an issue? (I'm grasping at straws here I feel like, haha).

This issue existed prior to my MOSFET install. Any thoughts as to what's going on here? In a previous post I share the results of my stator test and the stator checks out, so I don't think it's that. Something else perhaps is going on here.
 

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As soon as you flip on the key you’re applying a load to the battery. That’s not entirely odd to see a voltage drop. Especially if you have standard bulbs (non LED), you’ll get your best readings if you can have a voltmeter hooked up while riding.
 

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Discussion Starter · #3 ·
As soon as you flip on the key you’re applying a load to the battery. That’s not entirely odd to see a voltage drop. Especially if you have standard bulbs (non LED), you’ll get your best readings if you can have a voltmeter hooked up while riding.
This is great for my own understanding as well, thank you for that insight. I do have standard filament headlight bulbs and turn signal (front) bulbs. Only the rear turn signals and brake light are LED (combination unit). So this makes sense.

What doesn't make sense is why with the new MOSFET R/R I'm not at appropriate charging voltage (~14 to 14.5V) when I'm riding at speed. My onboard voltage meter (again, connected up to the turn signal wire in the headlight assembly) only yields me ~12.5 or 12.7V at speed. I'll check it again later with my hand held volt meter directly on the battery while revving (maybe the onboard voltage meter isn't calibrated correctly).
 

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Discussion Starter · #4 ·
This is great for my own understanding as well, thank you for that insight. I do have standard filament headlight bulbs and turn signal (front) bulbs. Only the rear turn signals and brake light are LED (combination unit). So this makes sense.

What doesn't make sense is why with the new MOSFET R/R I'm not at appropriate charging voltage (~14 to 14.5V) when I'm riding at speed. My onboard voltage meter (again, connected up to the turn signal wire in the headlight assembly) only yields me ~12.5 or 12.7V at speed. I'll check it again later with my hand held volt meter directly on the battery while revving (maybe the onboard voltage meter isn't calibrated correctly).
I just confirmed that the on board voltage meter is accurate.
 

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My voltmeter is hooked up to my accessory leads as well and it’s not the greatest voltmeter either but it works. Sometimes it’s off a few tenths of a volt when I compare it to my multimeter across the battery.
You could pull out the fuses for the lights/accessories and start it to se if it yields any different numbers a different rev ranges.
 

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Discussion Starter · #6 ·
My voltmeter is hooked up to my accessory leads as well and it’s not the greatest voltmeter either but it works. Sometimes it’s off a few tenths of a volt when I compare it to my multimeter across the battery.
You could pull out the fuses for the lights/accessories and start it to se if it yields any different numbers a different rev ranges.
I'll try this and report back with updates. Thank you.
 

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12.7v at speed is really low.., especially if the fan is off. Something isn't right. That's practically no charging at all but there must be some output because it's keeping 12.7v with all the lights on.

Tanner had an all new charging system and wasn't making good voltage. The Two Wire mod fixed it.

I hate to bring up another mod, but something is pulling the voltage down.

I don't know if it would help to pull fuses while watching the voltage, engine running. Maybe...
 

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12.7v at speed is really low.., especially if the fan is off. Something isn't right. That's practically no charging at all but there must be some output because it's keeping 12.7v with all the lights on.

Tanner had an all new charging system and wasn't making good voltage. The Two Wire mod fixed it.

I hate to bring up another mod, but something is pulling the voltage down.

I don't know if it would help to pull fuses while watching the voltage, engine running. Maybe...

Just trying to figure out how to have the bike running while drawing the least amount of load. Wouldn’t pulling the two 10amp fuses cut most of the lights out of the picture?
 

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Just trying to figure out how to have the bike running while drawing the least amount of load. Wouldn’t pulling the two 10amp fuses cut most of the lights out of the picture?
Yes it should.

I think it has some output, otherwise the voltage at speed would be closer to 12.0v, even 11.
 

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If I’m in traffic and the fan kicks on my bike will show 11.x on the meter if I’m sitting for a while. My idle is right around 1000rpm. As soon as I can move and get on the throttle the meter jumps up to 13.x. The highest I’ve seen on it is probably 14.2 on my dash meter which probably translates to 14.5 directly at the battery. This takes into consideration the cheap onboard voltmeter and any loss across the bikes wiring through the accessory leads.
 

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Discussion Starter · #11 ·
12.7v at speed is really low.., especially if the fan is off. Something isn't right. That's practically no charging at all but there must be some output because it's keeping 12.7v with all the lights on.

Tanner had an all new charging system and wasn't making good voltage. The Two Wire mod fixed it.

I hate to bring up another mod, but something is pulling the voltage down.

I don't know if it would help to pull fuses while watching the voltage, engine running. Maybe...
I completed the two wire mod, but I still have low charging voltage. Next I will start to pull fuses, but before I do are there any fuses I should stay away from and NOT pull while the motor is on? (also, as a reminder I now have the MOSFET R/R, blue wire mod, and two wire mod...just in case if this impacts the answer).

So what should the fuse pulls show...if there is a trouble area with the headlight system, or tail lights, or main, etc.? I'm hoping this leads me down another path because do you think the stator is the root cause? Last time I did the stator test I got good consistent resistance, good voltage at idle (20V) and 3,000 RPM (56V) and the ground test passed.
 

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If you pull a fuse and voltage rises significantly, that circuit has a problem. A minor rise is expected because lights may shut down, etc.. This test may not prove anything.

The mosfet install bypassed all the old RR wiring, correct? I'm trying to think of where the short can be.

With a good stator and mosfet kit, you should be able to remove the positive wire coming from the mosfet at the battery and read really good voltage on that wire, like 13.5-15v. So try that. I think that should prove if the system works or not.

If it has good voltage there, then we have to look at the battery and electrical system.
 

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Discussion Starter · #13 ·
If you pull a fuse and voltage rises significantly, that circuit has a problem. A minor rise is expected because lights may shut down, etc.. This test may not prove anything.

The mosfet install bypassed all the old RR wiring, correct? I'm trying to think of where the short can be.

With a good stator and mosfet kit, you should be able to remove the positive wire coming from the mosfet at the battery and read really good voltage on that wire, like 13.5-15v. So try that. I think that should prove if the system works or not.

If it has good voltage there, then we have to look at the battery and electrical system.
Yes, the MOSFET regulator bypassed all the old R/R wiring.

I pulled fuses and found that with the headlight fuse out, I'm back at nominal charging voltage! I finished an hour long ride last night at sunset with a battery that reads 100% charge! So I'm going to ride again today after work to make sure all is the same. And next on to troubleshooting! Is it the Amazon headlight I put in over Christmas break? Is there a short or some issue in the headlight housing? We shall see!

Thank you for the guidance and troubleshooting help. I'll come back to post a summary update of everything, because this bike has never been running better. Also by the way the pickup coil mod is a MIRACULOUS improvement in hot starts! Wow!
 

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Is it the Amazon headlight I put in over Christmas break? Is there a short or some issue in the headlight housing? We shall see!
Wait, were you riding at night without a headlight?!?

What's the headlight you put in? LED? I wonder if the load is improperly sized. This bike has an auto filament switch that detects a burned out filament and switches over to brights (at reduced brightness) if the low beam is burned out, or vice versa.
 

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Alright, at least we know it can put out good charging volts. Now to find the power drain.

So you rode without the headlight and it had good voltage. Does the headlight have a normal amount of brightness when it's on?

Assuming the blue wire mod is done correctly, I suspect the headlight or the wiring to it must be the problem.

Does the high/low beam switch correctly?
 

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Did you replace just the headlight bulb? If so I’d start simple by just pulling the bulb and see if that has an effect on your reading.
 

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Discussion Starter · #17 ·
Wait, were you riding at night without a headlight?!?

What's the headlight you put in? LED? I wonder if the load is improperly sized. This bike has an auto filament switch that detects a burned out filament and switches over to brights (at reduced brightness) if the low beam is burned out, or vice versa.
I'd never ride at night without a headlight. I take this sport/hobby very seriosuly when it comes to safety (all the gear all the time). I rode "last night" before sunset. My wife and I eat dinner early so anything after dinner to me is "night". ;)

The headlights I got are ultra-white Xenon HID bulbs from Amazon:

I haven't yet tested the running voltage with the fuse back in but the headlight removed. I will soon, which will nail down the root cause of the problem to this specific bulb. Unfortunately, I don't have any data of what the running voltage was prior to changing the headlight. So stay tuned. What do you make of this bulb? Do you happen to have any other good recommendations for bulbs (LED or otherwise) that you've seen work well on these bikes?

If the root cause is truly something related to this bulb, I'll want to replace it with something else bright/white.
 

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I looked at the link but I didn’t find what the wattage of this bulb is. For sanity you can leave in the fuse and meter across the headlight plug. At least that’ll tell you what voltage is being delivered to the bulb

Here is the bulb I have. I’m real satisfied with it, but I did have to remove/bypass the RLU. Before I did it both the bulb and the high beam dash light flickered. Before you change your bulb it's probably best to pinpoint if it’s the problem or not.

SEALIGHT H4 9003 HB2 LED Motorcycle Headlight Bulb, High/Low Beam, 6000K Xenon White https://www.amazon.com/dp/B071Z7RHY...abc_FNK6REFX7XMA2GQQZFQ1?_encoding=UTF8&psc=1
 

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Discussion Starter · #19 ·
I looked at the link but I didn’t find what the wattage of this bulb is. For sanity you can leave in the fuse and meter across the headlight plug. At least that’ll tell you what voltage is being delivered to the bulb

Here is the bulb I have. I’m real satisfied with it, but I did have to remove/bypass the RLU. Before I did it both the bulb and the high beam dash light flickered. Before you change your bulb it's probably best to pinpoint if it’s the problem or not.

SEALIGHT H4 9003 HB2 LED Motorcycle Headlight Bulb, High/Low Beam, 6000K Xenon White https://www.amazon.com/dp/B071Z7RHY...abc_FNK6REFX7XMA2GQQZFQ1?_encoding=UTF8&psc=1
Wow that LED headlight looks amazing. Was it a simple plug and play installation as far as the locking ring goes? That what it says on the link but I'm checking with you to confirm. But yeah, you are right that first I'll need to nail down the root cause before going down this route.

What do you mean by remove/bypass the RLU?
 

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Discussion Starter · #20 ·
If I’m in traffic and the fan kicks on my bike will show 11.x on the meter if I’m sitting for a while. My idle is right around 1000rpm. As soon as I can move and get on the throttle the meter jumps up to 13.x. The highest I’ve seen on it is probably 14.2 on my dash meter which probably translates to 14.5 directly at the battery. This takes into consideration the cheap onboard voltmeter and any loss across the bikes wiring through the accessory leads.
This is EXACTLY what I'm seeing as well. When my fan kicks in sometimes my voltage drops to yellow (I forget what this correlates to...maybe 12 or 12.5V). Then when the fan kicks off I'm back to 14.5V.
 
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