Maxim computer questions

I have developed a small glitch in the "check" (computer) system on the Maxim.

POs have disconnected/disabled the sensors for the stand, battery, and fuel, so when the bike is first started those items remain on the list after the system runs its self check. Press the reset button twice and red light goes out...good to go.

The other day, I look down in the middle of a ride and the whole list is displayed with a steady red light. Hitting either button has no effect...this display is locked. I few miles later, it's running a self check again and 2 presses leaves the display at the normal (for my bike) display of stand, batt and fuel with no light. A minute or so later, they're all on again.

Obvoiusly, there is some knid of connection problem and I'll have to do some fiddling to find it. What would be very helpful (since I don't have an owner's manual) would be to know exactly what should be displayed after pushing either of the two buttons. What is the difference between a steady red and a flashing red, etc. Any connections in particular that I should focus on.

Many thanks, guys.

Tim Hartney

 

Update...

Apparently the alternator has suddenly quit or else one of the main fuses blew or broke a connection...battery fully discharged a block from my house. I thought those blinker indicators looked a bit dim!

PO had installed inline glass type fuses on the circuits that were originally in the fuse block. I just bought a new blade style fuse block and had planned to wire it in soon anyway. Looks like that job just moved up the list. I suspect that these problems are related. The plan now is
1) Get the battery on a charger (it was new last fall)
2) install the new fuse block and check all connections in that area
3) install the charged battery and get her started in order to see if there is any output from the alternator.

Got to leave town for a week tomorrow, but I will post updates hopefully next week.

Tim

 

Sometimes it helps to disconnect and reseat all your plugs also. My blinkers started functing intermittantly on my XJ1100 and I just replugged everything and it was fixed.

I took the bulb out on my warning light, my full computer system works, but about 4 years ago the battery sensor had just deteriorated to about nothing, surprized it lasted 20 years sitting in battery acid, so my "BATT" is on all the time now, and it's been that way for awhile.

 

My batt sensor is long gone. Not sure where the wires for it are...probably taped up and buried somewhere. Same with the stand sensor. As for the fuel sender...when I removed the tank a couple of months ago, you could see where the wires were completely burned through. I clipped what was left of them for now. Maybe someday I'll get all that stuff working again---

OTOH

I hope I haven't cooked a bunch of stuff in the electrical system. I found a BIG mess with the 3 main alternator wires at their connections behind the battery. Last fall after I had the bike for only a couple of months I started snooping around under the seat and began checking all the connectors I could find. The main 3 wire plug was partly melted, which I assumed to be from a dirty connection. I chipped away the remains of the plug, cleaned the connectors, then seperated and taped the 3 connections.

What I found last night was lots of melted tape and the 2 outer cells of the battery were way low on water. The battery has been on a trikle charger all night and hopefully it's not toast. I've re-cleaned and reconnected the 3 wires, this time using shrink wrap insulation followed by tape. What my enquiring mind now want to know is what got those wires hot in the first place? I suspect that this isn't really a dirty connection problem at all, but a regulator or alternator problem...as in too much current going through these connectors.

I've been a bit lazy about checking on the battery since its install last fall, but in my defense, I've only put a couple of hundred miles on the bike since then. It seems to me that 2 almost dry cells with that few miles again says TOO MUCH JUICE getting to the battery. I may be in the market for a regulator soon, and possibly an alternator rebuild.

 

The MELT is a sign that the bike was hooked-up to a very-high amp situation. Probably a jumper-cable job from a late-model heavy-duty alternator car or SUV that was running when the cables got hooked-up.

Check connections between Voltage Regulator and Wiring Harness. Inspect the pigtail from the Regulator. Look at connection for Red Wire. If the connection is scorched or melted around the Red wire ... the Regulator took a hit and is likely burned-out.

Pull cover off Alternator Cover, on left side of bike -- the Round Cover under the Carbs. Check to see that the Brushes weren't burnt ... or cracked-off from arcing at the Rotor. Minumum Brush length = 10mm.

 

Thanks, Rick. It does have a history of jumping, (don't ask me how I know this) but that was prior to the new battery and first attempt at these connections. I will have a look at the items you have mentioned later today. Is there anything potentially bad about mixing up the 3 white wire connections, since the plug is gone? I doubt that they are connected to the exact same wire they were prior to the plug meltdown. Also, are regulators easy to obtain?

 

Fortunately, the Regulator is common across a great number of models and years. The person who'd know about the loose wiring issue would be Robert.

But, with the connector being gone ... I doubt there wasn't harm done to the internals of the Regulator ... the Diodes and soldering points don't take much heat on them before they fail.

 

It shouldn't hurt if you get the 3 white wires from the alternator system mixed as they all generate near the same range of A/C and then go through the diode pack and rectifier. The diode pack will only pass through half the sinewave converting to D/C, then it goes to the regulator to be a controlled D/C voltage between about 9 - 15.5Vdc.

Sure sounds like the PO made a real mess of your wiring harness. You can pick up White Molex plug sets that come with replacement pins that snap into the plug to replace any of your damaged plug units at most Radio Shacks or any other good Electronic's supplier. I always recommend after crimping them to also lay some solder into them, as the crimp arms are always small and are often hard to get a great crimp using small needlenose. Unless you have the proper crimp tool.

 

Confirming that you can cross connect the white alternator wires with no ill effects. As for the 3 pin connector they all go to, this meltdown is common. It is the result of 20+ years of corrosion, bad alternator brushes, and/or poor connections. As Rick pointed out, loose wires will create a high current situation. I'm opting for the corrosion angle but with all of the hacking your harness has suffered, it could well be something shorted.
If it is the wiring, Russ's suggestion is a great way to go.
If it is the corrosion issue that I'm thinking it is, best fix is a new harness.
Loose connections you can clean and repair in an afternoon.
Check your alternator brushes and rotor as Rick suggested and eliminate that as an issue. Better still would be to clean everything in there up and pop in a new set of brushes, odds are really good it needs them anyway.
Give us the skinny on what you find out.

 

Got some time to look things over this morning. No obvious burning or scorching anywhere but at the 3 white wire connectors. My attempts at soldering the other day on the Honda were, well, not pretty, so I went with connectors. I thoroughly sanded and cleaned two, replaced one, and generously coated with dielectric grease. I then sealed each connection with heat shrink insulation and wrapped with elect tape. Probably not as good as soldering, but solid, well sealed connections nonetheless.

I also finally got around to replacing the inline glass fuses installed by the PO with a modern 4 circuit blade fuse block. When I unwrapped the tape he had wrapped things with, I was pleasently suprised that he soldered pigtail extensions to each of the fuse block wires. Tape always looks a bit sloppy but the connections were quite solid. I shrink wrapped the pigtails' solder joints and wrapped with a bit of fresh tape just for a little extra protection as the heat shrink stuff seems kind of thin to me. I have a proper crimping tool and chose to crimp the wires in the circuit bolck...again, not soldered but good tight connections. It sure looks better than the nest of wires and inline fuses that were in there before.

The regulator shows no external signs of trouble. Wires and connector plug look fine, although the plug prongs could stand a cleaning and greasing. I will definitely replace the regulator...the condition of the battery and white wire connections just scream "too much juice!". I'm debating if it will be worth it to chance a used one from eBay or just pay the piper and get a new one and be CERTAIN to have a functional regulator. Looks like around $150 new and $60 for a couple I saw today. Opinions?

Battery seems OK. Topped up the 2 low cells and after 13 hours on the trickle charger it showed 13.25 volts. The acid test will be how it does under a load.

Alternator I didn't have time to get to, but I agree that just planning on new brushes would be the wise choice. Hopefully, nothing else in there is damaged/worn. Assuming all it needs is brushes, where do I get them? Are rebuild kits available from the dealer? Any better sources?

I won't be back from my trip until Monday and I'll post what I find with the alternator Mon night or Tues.

Thanks for all the help guys.

Tim Hartney

 

Keep Pluggin' ... just for the PUN of it!

Pull the Alternator Cover. Measure the brushes. Check the Rotor and Meter what you can.

If it will run. Run it and Meter the Voltage at the Battery during the START and a Run-Up. Check the Regulator against this profile:

Baseline 12V with the Ign Off
Slight hit for Key ON
Drop to 9 - 11V (+/-) for the START
Holds at -- at least 11V during low idle.
Gradually increasing as Rev's are Run-Up.
Beginning to rise through 12V as rpm's near and exceed 1050
Increasing to approx. 14.2 V at 1875 rpm
Steady charging voltage 14.2 - 14.5V at all rpm 2K and above.

You might not need a Voltage Regulator ... but, I'd have a spare handy if I was you.

 

I would hold off on buying a new regulator until you check the voltage output with the bike running. Do you have a maintenance manual? If you do, the process is fairly simple, follow the bouncing ball.
If you don't have a book, get one.
Quick and dirty is that you should read approximately 13 volts with the bike running +/- 1 volt. Anything less than 12.8 is suspect.
If you need, I will spell out the test in the Haynes for your use.

 

Thanks, Robert. I do have a Haynes manual and their procedure uses 2 multimeters so I'll have to borrow one to do thier test. My main concern is that it is allowing too much current rather than too little. If it is allowing the alternator to overcharge, what might I expect to see on a single voltmeter? At what rpm is the alternator maxed out, typically?

 

I don't think it is a case of allowing too much current.
If you read anything over the 14 VDC @ 5000 RPM (Pg. 215 top of the page) specified, then you have a charging issue. A good indicator that the system is pumping out too much is a hot battery and battery cells that dry out really fast, say 2 day or so. Harbor Freight sells a usable multimeter for $4.00 darn near every sale flier. Pick one or two up, they make great gifts and are darned handy to have around. I carry one in my kit for all my vehicles.
If you have a friend with an inductive pickup ammeter, you could do a amperage test, but those aren't something the everyday joe would have lying around (I do but it is not working correctly, sigh, Harbor Freight to the rescue).
Rick's earlier post gives you a very good step-by-step, I would follow his lead and, should everything check out, set your fears to rest.

 

Thanks, Robert. I'll try Rick's procedure and let you guys know what I findNext week.

 

It pretty much boils down to seeing that there's 14 - 14.2V (maybe 14.3, 14.4) happening at the battery terminals when the bike is revved-up over
1,875 - and hold steady at 14.2>V at 2,000 rpm's and above.

 

Got back today and ran a simple voltmeter hookup to the bat after reassembly. Looks to me like time for a regulator:
Voltage with ign switch on and not running: 12.2
Cold started instantly
Idle-1000RPM: 12.4
1500RPM: 14.3
2000RPM 15.3
3000RPM 15.2
4000RPM: 15.4

BTW, the computer seems to be back to its normal behavior. Guess all those glitches were trying to tell me something.

THanks for all the help, guys.

Tim

 

Tim, before you write off the regulator, try another meter. Sometimes the internal resistance on the cheaper units can cause slight errors. You may well be at the razors edge voltage wise and the meter could be leading you astray. From your readings, I'd say it deserves another look before spending the cash on a new regulator. Incidently, I'd like to get my mits on your dead regulator if the voltages don't fall into line. I'm looking for dead/almost dead parts to tinker with so I don't have to hack up my functioning units. I pay postage.

 

OK Robert. It's yours if I replace it. Today's gonna be gorgous, so I'll be ridin much of it (it's nice to have 2 bikes sometimes). Gotta leave again tomorrow for 5 days. If there's time today, I'll try another meter (maybe run the 2 meter test procedure from the Haynes manual), see what I find and let you know.

 

Robert,

I've decided to order a new regulator. PM me with your address. I'll try and get it off to you today or tomorrow.

Tim

 

Put the new regulator in and took her for a 110 mile ride yesterday. all connections look fine. Problem solved. Hope the clutch can wait until fall or winter. Thanks, everyone.

Tim

 

Thank you for the dead regulator, I'm going to start disecting it here at work this week.