82' xj750 maxim repairs.

So I can't find a wiring diagram that matches all that well and decided to just open it up and chase the wires. I've got them all labeled except these two that go into where the odometer is. The black plastic piece is not coming out and don't want to break it. Would these be just more lights?

 

At this rate I'm gonna owe ya some beers for saving my butt!

 

That is a reed switch that is used to provide pulses to the auto cancel unit for the turn signal flashers. You will need to wire that up if you want to keep the auto cancel function.

 

Thanks! Seeing as I had to eliminate that function when I went ahead and bought LEDs not knowing any better, it'll be one less thing to wire in.

 

there a wiring diagram that allows you to keep the cancelling function with led lights.

 

That was brought to my attention before but the auto cancel gone doesn't bother me.

 

So I have everything wired up and it's all working good except for the tach sits near zero at idle but moves smoothly upward with throttle. I'm assuming low voltage at idle is causing this problem even though my old tach read fine. I'm probably right in assuming it's from me re wiring this, but any shot in the dark ideas out there? I've checked the connections and with the motor off/key on I'm getting 11.58v at the tach connection in the headlight bucket. And the same while running at idle.

 

Edit: I am now getting 13.5v with the black ground and grey wire to the tach, and 12.58 with ground on the black and positive on the brown wire but the voltage stays around 12.58 then goes down to 6 for a split second and then back up to 12.58 ish.. I sure done opened a can of worms now haha.

 

My diagram shows the grey wire going to the tci unit and the coil, and the brown wire to the signal 10a fuse

 

could be the coil is misfiring for some reason or bad connection at the connector.

 

Did you ever for sure identify the gauges as to which bike they came from? I thought I read earlier that the new gauges had a mechanical tach and your original was electric?

 

I'm almost positive they came from a 79 xs1100 not an 81 like the marker said but I'm not sure 100%. Oe tach was electric and so is this one. Lots of cool gauges at the yard but 80% of them had mech tachs so I avoided them.

 

After a little test ride. The Speedo is a bit slow ( but catches up ) and the tach bounces.. gonna do some research into what would be making it possiby do that and also chase the signal wire all the way to the coil and tci unit. It's strange because the old tach worked fine, never a hickup, so it'd be odd that something happened at that same time to the wire somewhere.

Would the two different tachs take a different signal or something since the 79 Yamaha might not have had a tci unit?

 

The bouncy speedo and misbehaving tach speak to them both needing to be cleaned and lubricated. The tach might have cold solder joints on the circuit board, so look at those too,

 

Good call. I'll pull them both off and open them up. I had the back of the tach off and it all seemed good when I was chasing what wires were what, but I'll take a closer look for sure.

There's two little nuts I didn't undo, so I can obviously dive a bit deeper into it

 

I can't seem to get in enough to get the circuit board out. The front glass and round housing are over the lip n won't even spin, the two nuts on the back just loosen the gauge / circuit board in the case.. with the sun coming in through the window I could almost get goodenough of a photo. The brown wire solder looks a bit worse than the grey wire but I'm also not sure what a cold solder is.



I'll keep trying to find a way into this tach.

 

A cold solder joint will be dull and often a little wrinkly. The brown wire in your top pic looks kile t might be a clod joint. When you get in there all you need to do is hit it with an iron to reflow the solder.

It seems to me that the gauge comes apart like this (maybe): Repairing your 700 gauges

 

They seem to match Ebay XS1100 Special. The XS1100 and I believe the XJ1100 get the tach signal form the AC Generator that is mounted directly to the crankshaft, most of the other XJ's get the signal from the TCI. However, I am not sure if it would make a difference. I can't recall anyone ever making this particular swap. +1 on above where bouncy gauges usually do indicate a need for lubrication - sometimes on the speedometer you can just lube the input shaft bearing from the outside and that will work.

 

On one of my older model bikes I had to bend the front cover off of the rim to remove and get to the internals. Here is a link for what I ended up doing, but I am not sure yours are like this.

 

I do believe this is what I have to do.

Ok thanks for the info that puts me in a direction atleast. The Speedo is just a tad slow on the response ( a few seconds ) , does not bounce at all. Will try lubricating the Speedo. The tach bounces but also doesn't read even close to right so I'm assuming it's signal/voltage related