Maxim gauges

[ajvot]

I finally got the XJ started today for the first time. I have a lot of tuning and buttoning up to do, but I have found another problem. The tach doesn't work and all of the LCDs on the dash stay on. With no tach, it will be pretty hard to get everything dialed in.
I'm under the impression that the displays should be blank if all is ok. Is this true? The warning light does not blink, but it is lit. Pushing the buttons makes no difference.
The display has backlighting, power, etc. Can anyone give me some pointers? BTW, I'm not quite sure of the history of the bike. I'm thinking maybe there could be some corrosion inside the cluster.
Thanks

[TopCatGr58]

Hey there AVJOT,

With the tach not working, you will want to check your charging system first thing! Have you cleaned ALL of the electrical connectors, pulled them apart, checked for corrosion and used contact cleaner, wire brush, etc.?? Get a voltmeter and check your voltage at idle and again at 2500rpm should go up to about 14volts, if staying at 12 or less, then problems with charging, could be brushes(XJ specific), could be voltage red/Rect!? That should get you started...the problems with computer could be due to poor voltage or dirty connectors!?
T.C.

[Jerry]

Sounds to me like you have corrosion or pinched wire in one or more of the connectors. The XJ cluster can be taken apart. There are 2 nuts that hold the cluster to the bike, then 6 screws that hold the covers together. Remove the screws and remove the back cover to get access to the wiring, dash lights, and connectors. (You also need to remove the speedo cable, and I find it helpful to remove the trim cover around the ignition switch.) Watch for and keep all the rubber anti-vibration grommets. Make a quick sketch of the wire routing; you will need it to put the back cover back on.

The red light comes on in a variety of error situations; it is a multi-purpose indicator. Amoung other things it looks at brake fluid levels - front and rear, oil level, and battery fluid level if you have one of the OEM sensor type batteries. (If the battery has been replaced with a non-sensor type, chck the Tech Tips section for a procedure to "fake" the sensor reading.)

The cluster will go through a self-test every time you start the bike, and all the cluster functions will light up in order. The wires are soldeed to circuit boards in the cluster, unlikely the problem is there, but the wires are routed around the mounting posts and through an opening between the covers. More likely a wire or harness (there are 3 or 4 connectors) got pinched between the covers or around one of the posts.

Finally, the XJ xluster is unique to the XJ....if you need a replacement your choices are somewhat limited!

[ajvot]

I have checked and cleaned all of the connections twice. I haven't checked the voltage. Seems obvious to me now that voltage should have been the starting point. BTW, the battery is OEM type with the sensor. I'll keep you posted. Thanks to you both for the suggestions.

[Jerry]

The other thing to check would be the brushes in the XJ alternator. (The XS doesn't have them, different design.) If these are hanging up and/or worn you won't get any alternator output. Part numbers are:

4G0-81611-10-00 Brush 1
4G0-81612-10-00 Brush 2

If you need to try a replacement guage cluster I have one with a bad speedo, could ship it to you but you would have to do the speedo swap. Let me know.

[ajvot]

I'm going to check the brushes tonight. I'll let you know what's up. Thanks for the gauge offer. I may take you up on it.

[ajvot]

Just got done checking the brushes. One is sheared off. I'll bet that's making a difference (sarcasm for effect). If you are holding the cover and looking into it with the brushes positioned at the top, there are two small wires that appear to come out of the windings and go into the piece that holds the brushes. They look like they might have some kind of small clip on the ends. Any one have a clue how these attach?
There looks like ther is a hole that they will go into, but is there anything special about what and where they go? I'm hoping I won't have to buy an alternator.
Thanks for the tips up to this point.

[flb_78]

I found out that the turn signal fuse also runs the Tach/dash assembly. May wanna see if the turn signals work.

[ajvot]

Turn signals, flashers, etc., all work great. Great tip though. After I found the sheared off brush and loose leads, I'm pretty sure I've found the culprit.
BTW, I checked with two different dealers today, and new brushes from Yamaha are about $30.00 per brush (2 needed).

[flb_78]

maybe you could take them into a alt/starter rebuilder, they may have some that will work. I know my dad used to use points off a 350 chevy in his 1978 suzuki 750.

[Jerry]

I'll have to pull the cover and look...has been several years since I lst changed mine, don't remember the details, but don't recall anything to special about hooking up the wires. Will also check my shop manual when I get home tonight to see what it says about replacing the brushes.

[Jerry]

Manual isn't clear on the wires, all it says is:

*************
E. Generator Brushes Replacement
The generator carbon brushes require periodical replacement.
Replacement is necessary after the first 13,000km (8,000 mi) and thereafter, every 16,000 km (10,000mi).

1. Remove the generator cover screws and the left-side generator cover.
2. Remove the screws and separate the brushes assembly from the cover.
3. Remove the pan-head screws and replace the old brushes to new ones.

*************

Thats it, all the manual has on generator brush replacement. I also checked in the engine rebuild section, nothing much there except you need a special tool to hold and another special tool to remove the alternator, nothing on any other wires. Looks like you need to go with your best guess!

[ajvot]

A fellow member is helping me out with this one. There are parts on the way. I'll let you all know how it pans out.
As far as the manual goes, it definately can be a little vague at times, but is still a "must have".

[ajvot]

Charging circuit

Ok, here we go. I have replaced the alternator (I can't give enough thanks to Czekus for the help) with one that looks brand spanking new (great brushes, no corrosion anywhere). I have replaced the field coil with the one from the replacement alternator. When I took the other stuff off the bike, I found several spots that the wiring was charred, and the connector was a little melted. I had noticed the connector before, but didn't think too much about it because the internal parts seemed ok.
I still don't have any charging circuit. I get a constant 12.3v, which does not vary with throttle position.
I am down to replacing the regulator/rectifier. Here's what I think may have happened to the PO. The reg/rect went out, when this happened, it may have shorted out the gauge cluster (the warning light is ALWAYS lit, but never flashes, and it does not cycle through the diagnostics). This may have all happened due to a poor connection from the alternator (the partially melted connector). I found the link that mentioned that melted connectors can come from poor connections because they are carrying the same current over a smaller area, thus creating way too much heat.
Tell me what you think. Am I on the right track, or grasping at straws?
Anyone have a reg/rect they want to get rid of? I thought I had a spare, but it's for something else.

[ajvot]

I replaced the rec/reg last night and checked the output. It moved up great and gave me 14+ Volts. Still no tach, so I'm just guessing at the rpm's. The gauges must be fried.

Here's the new problem. Starts and idles great. Runs a slightly rough under throttle. I haven't been able to ride it under load to get everything dialed in yet. The problem is that I rode it around the block, then when I was just about home, it died, just like I had hit the off switch and both pipes let out the biggest backfires I've ever heard. The bike wouldn't retart, but would backfire. I'm at a loss. I've done several searches, but can't seem to find my symptoms. Any suggestions?

P.S. I have Seafoam in with a full tank of fresh gas.