Bike doesn't start in cold weather

As I come closer to restoring my 81 XJ550 Seca I still haven't figured out the weak charging problem. It idles at around 12volts and maybe peaks into the 13's when I rev it up to 3000rpms. I've brought it to two different shops and one says it's the RR and another says it's the stator. When I did tests on both of these items they both seem to check out fine. Nevertheless, I tried replacing both of these items with USED parts off of other bikes and I got the same exact results. Is it possible that a used or original 37 year old stator and/or RR can be weak so that when it's operating, it can't put out the voltage it used to? Or is it more black and white where they either work or they don't? Should I just go for broke and try replacing these items with brand new parts?

 

The voltage regulator could be the problem. Do you have bulbs failing? If you changed the stator and rotor and then replaced them and got the same results you could have a voltage regulator problem.

 

I'm assuming when you say the voltage regulator you are referring to the Regulator Rectifier (RR). Bulbs have been fine. I have changed the stator, rotor, and regulator rectifier with used parts and nothing changed.

 

Yes RR is right. I am sure input voltage is critical to the rotor. You could have resistance in the cables to the carbon brushes. There are lines on them showing the wear limits and the brushes themselves can deteriorate with age. Also the slip rings on the rotor may need cleaning. Check all electrical connections to and from the alternator and check the brushes before buying other parts that is how l would check it. It could be a voltage drop problem. It cannot be a short to ground or an open circuit if voltage is rising when you blip the throttle.

 

what does it do/not do that your trying to fix?

 

My Turbo's headlight is fairly dim until it revs to 2K or more.....always figured it was just the way the bike was. These early Japanese charging systems were at best, bad. In reality, Lucas was probably worse than Nippon at this point, but not by much!

At least with the older ones, we could adjust the voltage. You can replace the rectifier with a modern one, just match the pins and look around 1999-2004 Yam, kaw, or reach out to these guys : https://www.regulatorrectifier.com/catalog/ I'd call and chat with them.

FWIW: has your connector for the alt fried yet? On our turbo's, it's a common malady best fixed by a permanent solder bond.

Good luck,

jeff

 

Corrosion. You may have corrosion in connectors and wiring. The KILL SWITCH could be corroded. Check the connector coming from the stator. You may find evidence of overheating and corrosion on the pins.

You may try this:
https://www.instructables.com/id/How-to-perfectly-clean-wires-in-minutes/


I avoid follow-up with dielectric grease as it is an insulator.

 

I did everything you said and more. I've changed brushes, checked connections, cleaned the slip rings on the rotor. The only time things look like they kind of improve is if I charge the battery. The idle voltage stays the same but when I rev it to 3000rpms it might actually charge up to 14.5volts. Still no improvement hence the reason why I wonder if I replace with BRAND NNEW parts, it might fix the problem.

 

three more things to measure, voltage at the battery after setting overnight, key off.
then turn the key on and check again
then check while it's cranking
i'd start shopping for a battery

 

then you might want to check it running, at the battery with the meter on AC volts (it won't hurt the meter)

 

I've done that. I've done EVERYTHING, believe me.

 

Again, I'm just curious about the parts themselves. Does an old stator or RR lose it's effectiveness over time and so I should replace them? Or are they simply designed to work or not?

 

Battery is brand spankin' new. That was one of the first things I replaced.

 

It is not charging at idle. It reads 12volts if I'm luck at idle and maybe into the 13's at 3000rpms. Charging is basically weak.

 

You have my attention JetmechMarty. What does the KILL SWITCH have to do with the charging system. The pins coming directly out of the stator all measure fine both when I check resistance and also when I turn on the bike and measure the AC output. I don't have the numbers to tell you exactly at the moment but I know that when I measured in the past that they all reach spec with no problem. So, tell me about the kill switch. Also, I cleaned up as much corrosion as I could find and I also used electrical spray designed to clean the connections. Nothing has worked yet.

 

no xj does

look here at the orange/green chart. now decide if you really have a problem
https://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

no

 

Have you changed out the fuse panel for the blade type fuses? While it won't increase the charge rate it will make it more efficient. I thought I had a new bike when I did mine. The XJ's do take a few RPM's to get changing.

 

Check

 

3000 rpm isn't much. What's it like at 5000?

 

It actually gets to charging voltage when I go to 5000rpm. It levels off around 14.5-14.6 volts but it takes about 5 to 10 seconds of staying at 5000rpms before it finally reaches that number. So, it does seem to be doing it's job when I'm actually riding the bike and I can see the volt meter on the bike reaching to 14volts (I know those aren't reliable but that's the highest it's gone in a while) If only it would go to 13.5 at idle and I'd be a happy man.

 

You do not have a problem with your charging system

 

Okay

 

My XS650 and XS1100 have everything running through the KILL SWITCH. If there's a voltage drop there, the spark gets weak, the current to the charging rotor goes low and so does alternator output. Have a look at your wiring diagram.

 

I agree with everything said above, however, a quality battery should have 12.7-13.2 Volts fully charged, therefore it should be impossible to have 12V at idle unless your battery is weak.
Be sure you have a quality battery NOT from Walmart!
Also the new AGM and maintenance free Optima style battery's won't charge right in old bikes... Don't ask me why.
My XJ the headlight dims slightly at idle, so they do have weak charge.
These bikes are screamers, 9000RPM and even cruising you should be running 3000+ RPM in any gear.
Mine turns 4500 on the highway, so provided you get 13.5+V somewhere around 3000, your battery is charging while you ride.
Hope this helps

 

...Or you're running the bike at idle long enough to draw the battery down. That's easy to do if the high beam is on, aux light is on (750 only), or you have accessories running. Running it to synch the carbs will draw battery voltage down by quite a bit. Even starting the thing can drop the battery below 12 volts in cold weather.


Also, my garden tractor battery is from WalMart (store brand). A 5 year battery that I've been using for 7 years. I wouldn't put one of theirs in my motorcycle, but I use them in everything else.


Also, also, I use an AGM battery in my XJ. It charges perfectly fine (you may be thinking of LiPo batteries, most of which now do charge fine in older vehicles, but earlier ones did not).


It's only been very recently (about 15 years) that vehicle charging systems have been built to charge the battery at idle. As the electrical demand at idle has increased due to all the fancy gagets we have now, the ability to charge at idle has become necessary.

 

So, it's possible that the connection at the kill switch is weak but is still functionable? I have actually taken it apart once to install a new starter button and I remember it looking okay in there but it's worth the voltage drop test. I'll check it out.

 

A lot of this seems to be almost personal opinion then anything. Some people are telling me no XJ charges at idle. Others are saying charging at idle is a new thing. The manual clearly says it should be at 13.5 at idle and mine clearly isn't. What's interesting is that it does go up to about 14.5 at 5000rpms which is basically in spec but once it hits idle again it's back down to 12 and this is with a freshly charged battery that's brand new! I'm just not sure anymore. I recently cleaned all the connections with a vinegar/salt solution and then followed it with a baking soda/water solution (works great btw and you can see the wires sizzle. cool)and I must say that charging improved slightly at the higher rpm's. So again, I wonder if changing out the stator or RR is the logical next step.

 

Seems to me that it's there or thereabouts. If all the relevant contacts are cleaned thoroughly and reassembled with dielectric grease you've done the best you can. Getting hung up on a few 100 revs ain't worth it in my opinion. But then I can be a lazy sod at times.

 

Joshua,

As I stated before, you do not have a problem with your charging system. Do not replace the stator nor the R/R unless you like wasting money.....

Don't fix what''s not broken.

 

Watching the voltmeter on my 650 that I have installed on my handlebars, at idle I get battery voltage or just very slightly above. As soon as the revs come up, the voltage goes right with it. At cruising rpm its charging between 14-14.5 volts. Near as I can tell this is normal and I've not noticed any adverse effects from it.

 

Chitwood, what you are describing is exactly normal....

 

Where in the world did you find that method? the salt/vinegar solution went right to the crimp and wicked up the conductors past the insulation, now it's in there corroding the wires. no the baking soda didn't neutralise all of it.

sounds to me like you won't be happy until you buy some parts, so that's what you should do

 

Dielectric grease is an insulator. Why would you do that? Keep that stuff away from me!

 

You are funny.

Have you ever done stand-up comedy.....& don't reply with " No...you only do it sitting down"

 

The grease gets scrubbed off from the parts that are making contact when the connectors are hooked up. Applying it is SOP in machine maintainance (my prior career). Keeps the corrosion and oxidation at bay for a very long time.

 

Please explain why you say this. Isn't it not working properly if I'm barely hitting 12volts at idle?

 

I found it right here on this site:
http://www.instructables.com/id/How-to-perfectly-clean-wires-in-minutes

 

Joshua,

I will run the test on my '82 XJ750J Maxim tomorrow for you.

Parameters will be Battery Voltage at:

1. Rest
2. During cranking
3. At idle after warm up
4. At 3,000 rpm
5. At 5,000 rpm

My bike is dialed in.......so we will see the results.......if similar to your resilts.....will find that acceptable ??

 

Charging does not occur at idle. Your system passes the tests for measuring charging voltage.
If you wish to change all the charging system components for new that is your perogative, but the money would be better spent elsewhere.

1. Both of your first statements are true, and both are saying the same thing. The charging system on your motorcycle was not meant to charge the battery at idle, precicely because the typical load on the electrical system does not require that the battery be charged at idle, and because it is quite uncommon for a motorcycle to be left at idle for an extended period of time.

2. Which manual are you using? There are several known errors in each of the three manuals that were published (Yamaha, Clymer, and Haynes).
The spec that you quote is not correct.

From:
the-information-overload-hour.27544
A link that I know you were provided with at least once.

Charging System Tests:

a) Adjust voltmeter to DC volts (20 volt range).

b) Place voltmeter leads to the battery terminals (positive to positive and negative to negative).

c) Start the engine.

d) Bring engine up to approximately 2,500 rpm's.

e) Compare the voltage reading to the specification given below:

For all XJ-series models, the maximum available charging output VOLTAGE should be as follows (all values are approximate):

* approximately 500-2000 rpms: 12.6 volts gradually increasing to 14.2 volts
* 2000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts (all models except XJ700-X and XJ750-X)
* 3000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts (all XJ700-X and XJ750-X)

 

If you are going to spend the money on a new stator and R/R , then make sure you buy a very expensive voltmeter......you dont want any bogus readings from a free Harbor Freight one....

Just a bit of humor here......no malice intended

 

Joshua, Test Results

This is on an 1 yr old AGM battery.......I keep my battery on a Battery Tender Jr. when not riding my bike on a daily basis.

Parameters will be Battery Voltage at:

1. Rest after sitting overnight....................................12.2v

2. Key in "On Position"..............................................starts to drop slowly from 12.2v ( due electrical system being charged & lights on, as expected )

2. During cranking.....................................................11.0v ( as expected , sudden temp drop due to starter button being depressed & starter motor drawing current to crank motor )

3. At 3,000 rpm..........................................................14.2v

4. At 5,000 rpm..........................................................14.4v

5. At idle after warm up..............................................12.6v



Results are as expected & within Yamaha specs......I am satisfied my charging system is doing its job....

I think you need to accept that your charging system is working properly......your battery will never indicate 13.5v at idle as you mentioned in an earlier post......however that is just my thoughts......

 

I know it. I remain a contrarian.

 

Thanks. I might be a little OCD about this. I'll check the same readings and compare.

 

that's great if your cleaning pots and pans but corrosive liquid and salt is bad for wires, that's why they have this stuff
http://store.caig.com/s.nl/sc.2/category.188/.f

 

Awesome. Now I know better for next time.

 

Hello everybody. I know this is an old thread but after two months of taking a break from my Seca 550 my uncle came into the picture and gave me renewed vigor to tackle the bike once more. Good news is that it's running and running strong. It's kind of the end of an epic 1 year journey. And it was worth every minute. However, do you ever really finish restorations projects?
I still have questions about the charging system. I rigged up my volt meter onto the bike to see exactly what the heck was going on while I rode around town. My battery was completely charged up at 13.13volts and I took off. The one thing that stood out as odd is that the bike SLOWLY and I mean SLOOOOWLY climbs up in voltage taking a good solid minute of no stop signs, stop lights or even slowing down before it hits full charging capacity at 14.82volts.. Why so long? In LA traffic you barely ride a minute before you either come to a stop light or run into traffic. So generally speaking I never reached full charging capacity while driving around town and every time I hit a stop sign I noticed the voltage at idle was slowly getting lower and lower. It originally idled at 12.13 volts but it got as low as 11.98volts. When I got home I measured the battery and it was at 12.62volts. Is this normal behavior for bikes of these times that still used the generator system? Shouldn't the bike get to full charging voltage within a few seconds of throttle? Could this be a regulator rectifier issue?

 

Hi Joshua, short answer is "yes it should". On my 550 seca, once the RPMs hit 2000 or so, I'm up in the 14v range. I haven't had to troubleshoot this on my bike, but I did put a new fuse holder in and all the lights got a bit brighter!
I'd recommend looking over the Electrical section of the catalog here since there's always a wealth of helpful information in there. https://www.xjbikes.com/forums/threads/xj-parts-catalog-section-d-electrical-system.44641/

 

how long had it been off the charger when you measured this?

i've never heard of "full charging capacity" if you mean maximum charging voltage, then 14.82 is a little high.

after a battery sets for a hour or so, that's what a full charged battery will read.

forget generators, your bike has a alternator just like your car.

depends on how much energy it took to start the bike, less than 5 seconds, yes. more than 20 seconds, no.

try doing this about five more times and see if the numbers stay about the same

 

this link at bottom of the page explains charging system. read itfor guides to getting most out of your charging system.
The Ultimate Relay, Switch, Sensor, and Diodes Guide

your bike has an alternator and voltage regulator for a charging system regulator is a bridge rectifier which turns ac into dc. not a generator

when your bike is running it is running off of the alternator and battery is charging through the main fuse while bike is running.

the headlight ,cluster back lights, and tail light and plate light as well as the tci are all drawing current.
the current draw will affect the rate at which the battery charges.

your grounds at motor, frame and ignition coils need to be spotless for best results so do the battery connections. all the crimps are 30+ years old,

take a look at the voltage regulator connector it may be melted and have poor connectins. resulting in voltage drop at connectors.

go to led back lights in cluster ,led tail light and plate light if you have one this will save you amps when the bike is running.

clean the copper rings with an eraser and spray it off with electronic connector cleaner check the condition of the brushes.

your bike was ment for lead acid battery or gel cell .

also clean all connectors for the always on lights to eliminate voltage drop

 

Joshua,

I think you should just buy my bike down here in San Diego.........PM me......no need for my XJ750 Maxim any more........I would PM you, but your message inbox is full.....