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81 Seca 750 brake and light issues

Discussion in 'XJ Technical Chat' started by Timbox, Feb 12, 2019.

  1. Timbox

    Timbox Well-Known Member

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    I just could not hold off, winter in WI driving me nuts. So picked up a Seca 750 R (I think) with a few miles on it. The battery cover is gone (normal) and the front brakes were locked up.

    Took the carbs to church, there were not that bad. I got a chance to use my sonic cleaner with the heating setting, that sure worked out good. Got them back together and bench sync is done.

    Tank was okay and looks like just a in-line filter should do the trick. If I see issues in the filter, I will soak it in Vinegar for a week or so to take care of it.

    Got the shims in the other day, but we are getting hit with a little snow here in WI, so I will not be heading out to the shop until the snow stops.

    My issues are these:
    1. The anti dive fork bleeders are broken off!
    [​IMG]20190211_134503 by Tim Brown, on Flickr
    On both sides.
    2. No headlight even though I have changed out the bus fuses in the head light bucket and main fuse system with spade type.

    I guess I just can't remember if this bike has a relay that keeps the headlight off until it start or not? I did check both headlight and driving light and they both are working.

    Here she is looking less than happy but getting some much needed TLC.
    [​IMG]20190211_134443 by Tim Brown, on Flickr
     
  2. XJ550H

    XJ550H Well-Known Member Premium Member

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    secs750relay.PNG you do have a headlight relay it also supplies power to the auxilliry light
    for headlight the relay sends power t o the high low switch then to the speedo then to headlight.

    alternator sends power to the diode on the white wire that is the power for relay. it will close when motor spins and starts generating power

    if the bike is an 81 it is a seca 750 no maxim that year
     
    Last edited: Feb 12, 2019
  3. Timbox

    Timbox Well-Known Member

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    HJ550,
    Thanks for the heads up, I thought as much, just know some of the bikes had that. I will get the new shims in, seal up the cover, slap the carbs back on and throw some gas at it. I am hoping that she fires right up, then to work on backing out those nasty bleeders. I am thinking if I can't get to them with a back out, I will drive a old small flat tip in there and see if I can vise grip them out with the post sticking up.
    This is another bike with no title, so I am either going to try to get it done through Vermont or spend the $100 and six weeks of wait time on the bonded title here in WI.

    Again thanks for the schematic XJ550H :)
     
  4. Timbox

    Timbox Well-Known Member

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    Tried to get those bleeders out after letting them soak. Broke two back out bits, used lots of heat and BP blaster. Boiled them a few times, then ended up trying to drill them out. I will just bypass them for now. I don't know if I can even drill them all the way out and re-tap that for a different size bleeder. So for now the lower brake line has been removed and just the lines going from the master to the calipers are there. Not too sure what that will have to offer, for now I am safe as roads are not ready to ride here in WI.
     
  5. Timbox

    Timbox Well-Known Member

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    Got the shims installed today and the valve cover all buttoned up. Installed the new NGK spark plug caps and the carbs. Hooked up the AUX gas and tried to fire it up. Well she wanted to go but had to put my hand over the back and of the carbs even with choke on. I found out the the head to carb boots were so loose that it was not pulling air through the carbs. Have them cleaned up and will add a little gasket prep to them before they go back on. The engine sounds good with the new shims in, glad it started and the head light came on after it started.

    I have to look at the AUX light to see if it is burnt out or the swx. The throttle cable is a little stiff too, so need to work on that. Carbs bounce supper nice on the bench but that throttle cable is not rolling back. The PO must have done something to it.

    With the left muffler being totally shot, it was funny to start the bike up and listen to it growl.
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

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    the cable needs to be lubed.
    there is a tool for lubing cables. or you can let gravity do it.
     
  7. Timbox

    Timbox Well-Known Member

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    XJ550,
    I will take the throttle apart and see what is going on with it. I will hit it with blaster and let it soak in, not buying that tool. I will even build a little fluid dam before I buy that tool. :)
     
  8. XJ550H

    XJ550H Well-Known Member Premium Member

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    cable lube.PNG

    photo from Haynes manual. you can also use a baggie to hold oil.
    and a shop vac on free end
     
    Last edited: Feb 23, 2019
    Timbox likes this.
  9. Timbox

    Timbox Well-Known Member

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    I found the issue with the throttle. It was not the cable, it was the throttle grip, the PO had put grease and or gasket compound in there! I could only guess that when they changed out the grips they over did it on the throttle side. Smooth as new now.

    How is the for a great mod by a PO!
    [​IMG]DSCN0138 by Tim Brown, on Flickr
    [​IMG]DSCN0157 by Tim Brown, on Flickr
    I guess I need to get a OEM filter and see what I can do to fix it.
     
  10. Timbox

    Timbox Well-Known Member

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    Made the ugliest YICS tool today. Tried to read and or follow some of the drawing from the site. I guess I missed something as the sizes of washers were too big. Anyway, found the correct size hose, washers and used a arrow shaft for the spacers. Once is warms up a little I will try and see if it isolates the carbs as it should. I little cool to be opening the shed to let the exhaust fumes out as I sync the carbs.
    [​IMG]20190227_165330[1] by Tim Brown, on Flickr
     
  11. XJ550H

    XJ550H Well-Known Member Premium Member

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    Make sure you get the little ports cleaned out before trying the tool if the holes are not clear it is pointless to use the tool
     
  12. Timbox

    Timbox Well-Known Member

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    What is the best way to clean them? I was guessing one of those longer cone shaped brushes and some chem tool spray. I should be able to tell on the sync gauges if it is plugged, there should be changes to the individual gauges. If they all move well then it is not sealing...best guess.
     
  13. Chitwood

    Chitwood Well-Known Member

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    I've sync'd mine with and without blocking the yics passage and really couldn't tell too much of a difference. If you are going to clean it perhaps something like a gun bore brush would work? Trouble is getting the little holes clean that connect the ports to the passage
     
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  14. Timbox

    Timbox Well-Known Member

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    Thanks to all for the suggestions, I think I will go with the bore brush and some chem tool. I have them sync without the YICS tool, sounds okay, I just like to have them very well synced. I guess I will leave it alone as long as she is running nice. I will try to clean out the YICS ports and she how it runs once when the snow clears.

    Got the air cleaner in the mail so Now I can box it all up and have it pull the correct amount of vacuum and or suction and do the sync.
     
  15. XJ550H

    XJ550H Well-Known Member Premium Member

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    hopps gun cleaning solvent and a bore brush will clean out the bore that runs through the cylinder head then there are little passages that run up to the intake passage .
    chacal (xj4ever)sells the tool for cleaning the small holes.
    I have a drawing of the passages I will look for it
     
  16. Timbox

    Timbox Well-Known Member

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    Today was nasty but spring nasty, rain. I was able to get to the Seca and give her it's new battery. Then I went to start her, interment lights came on but nothing to do with the started. After I jumped the solenoid, went to the right handle bar and took it off again. Sure enough, pinched one of the stop engine wires when I put it back together. So the new 10 AMP spade fuse and she was working as it should.

    Drained the oil and changed the oil filter along with the "O" rings that came with the kit. One of the great members on here was able to find me a 4-1 header as this bikes exhaust system was rusty and done.

    The title came in so I guess I better get this bike ready to go for the spring weather. If you have been following my 96 BMW R1100GS build, that bike just feels weird and is more or less a gutless wonder. The Seca will be my secondary fun bike.
     
  17. Timbox

    Timbox Well-Known Member

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    Got the 4-1 exhaust on and the clutch cable. New exhaust sounds really nice and once it get all the little rust part blow out of it will be good to go. Still have a issue with the AUX light, I am guessing it is the relay. I check both the light (good) and AUX swx (good) so I am guessing it is the relay not working. I need to get the bike out of the shed and get it de-greased and some power spray the bike clean. I am guessing there might be a head gasket leak but it could have been from the valve gasket. I hope to have taken care of that when I did the shims.

    We are getting nice riding weather, the news is reporting motorcycle accidents already, most caused by bikers hitting sand and gravel left over from winter road conditions. We just lost the snow in the shaded areas and have not had a hard rain to wash off the roads.
     
  18. Timbox

    Timbox Well-Known Member

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    Have time to work on this bike again. I took the carbs off again, the throttle seals are leaking and I can't get a steady running motor. There is a leak someplace and I would bet the throttle seals. I will have to find out what "O" rings go in there. I think I read on one site #10 but I will have to see. I sure like this old bike and the sit on not sit in type bike. Hope to get them apart today.
     
  19. XJ550H

    XJ550H Well-Known Member Premium Member

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    it is #11 buna N o rings or xrings 2 for each side
     
  20. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    If your headlight works, then the problem with the AUX light has nothing to do with the headlight relay.
    The aux lamp taps into the headlight hot side after the relay.
    Check the wires. I'd start at the pigtail from the lamp to the harness in the headlight bucket. Might be a pinched or broken wire.
     

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