1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

83 XJ750 Midnight Maxim slow-to-respond tachometer needle

Discussion in 'XJ Technical Chat' started by Jiggs the Geezer, Apr 19, 2021.

  1. Jiggs the Geezer

    Jiggs the Geezer New Member

    Messages:
    12
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Alberta Canada
    Tachometer is slow to respond, needle just crawls up, but eventually gets there, then just crawls back down to either idle or zero if shut off. This model is electronic tach, not cable-driven.

    On this Midnight Maxim, speedo and tach are in two retro-classic bullet-pods, rather than a "dash" like normal Maxims or Secas. Took the headlight out to work slack into the harness to the instruments. Dismounted the instruments, took four screws out to take the pod-cups off the instruments, just worked them back over the mounts and harnesses, did not disconnect anything inside the headlight bucket. Got the covers off the back of the guages, took the mount off the tach (2 x 8mm nuts) to access the screw terminals for the three wires. Took the rubber-cupped tach-backlight bulb out. The tach is three wires, V+, ground, and coil, held to the tach with three screw terminals, took them off. There are four screws holding the white-plastic inner guage cup to the cluster, took them out. The white cup holding the tach is now free, be crazy careful, the tach pointer is super-delicate. There are two screws holding the tach guage itself into the white inner cup, take them out, continuing to be careful handling the guage mechanism. The shaft of the guage goes through the face, and the needle is on the end of the shaft, no further disassembly necessary. When I pushed the tach needle up off zero, it moved very very slowly back to zero. Holding the guage face up, I used aerosol electronics cleaner spray to clean everything under the face. Keep cleaner away from the face, it will eat the paint and make the black and red and white all run together. That would be ugly. After a few seconds of spraying, the tach needle moved normally, moved it up and it dropped quickly back to zero. Sprayed some ptfe white teflon powder aerosol lock-lube into the part of the mechanism where the shaft and bearings are, again, keeping spray stuff off the black face and white numbers and red needle. Put it all back together, and blipping the throttle blips the needle freely like it should. Fixed. Nothing to buy but some electronic parts cleaner and lock lube, which is already in my shop.

    Just keep the spray stuff off the face of the instrument.

    And then I sold my beloved XJ750 Midnight Max to my local carburetor guru. :( Gotta pay bills. 61 yrs old, laid off due to covid, things don't look good.

    I have an FJ600 oil cooler, filter sandwich adapter, and hoses. Sandwich adapter will fit on XJ750 and XJ650 maxim and seca, will need some oil resistant hose and t-bolt band clamps to connect sandwich adapter to cooler. All the frame mount bolt points are already on XJ650 and XJ750 (air cooled) so this engine oil cooler would be an easy bolt-up that would help keep an XJ not-so-hot in 90F+ that we hardly ever get in this part of Canada. Whoever wants the oil cooler can have it for postage. Send an email to jiggseob@hotmail.com
     

Share This Page