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hello and ... front brakes seca xj750rj

Discussion in 'XJ Technical Chat' started by joeseca, May 30, 2019.

  1. joeseca

    joeseca New Member

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    hi everyone.

    just picked up a 1982 seca xj750rj for free ... lucky me. actually, got a 750 virago as well, but thats on the back-burner for now.

    LOTS of miles and sitting for 15 years (according to the PO) but it seems complete, has good compression, and does not appear to have been abused.

    can't do much about making it run 'til my parts come in, but the front brakes were sticking so bad that it was difficult to push around so i decided to remove and clean the calipers. that part went fine so i re-installed and attempted to bleed ... nothing ... no air, no fluid, nothing is being pushed through either the bleeders, including the anti-dive, or the banjo bolts. by the way, i have some motorcycle experience (hondas) but never touched a yamaha.

    from the searching i have done it seems that these are notoriously difficult to bleed but ... getting nothing ??? does this indicate a bad master cylinder ?

    i read that i should attach a syringe filled with brake fluid, open the bleeders and leave it overnight. assuming that fluid can make it's way though the system at all, wouldn't it all just drain out being left open that long ?

    looks like a great forum, glad to have found it. looking forward to your suggestions.

    thanks
    joe
     
  2. Timbox

    Timbox Well-Known Member

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    Welcome to the site! I too have just restored a bike like yours. Do you have the anti dive front forks on yours? I know my bleeders were done and I had to bypass them to get my front brakes to work. Playing with that master cylinder behind the headlight was fun. I used a small hose to fill the mater as I bled it.

    Have you taken anything and stuck it down the master cylinder fill hole? If it dried out or is there fluid and it is clear. If the master is all dried out, you will have to take it completely apart and rebuild it to get it to work. I am guessing sitting for 15 yrs that would be your best bet in the first place.

    In the upper right corner of each page is the xj4ever icon. https://www.xjbikes.com/forums/forums/xj4ever-supporting-vendor.23/
    They have all the great parts you will need to rebuild that and anything else on your bike. On that same page you can find so must information that you should take the time to read. It will really help you out and give you a little more insight to your bike.

    Lots more folks will be along shortly to give you all kinds of info about your bike.

    Again welcome to the site and when you get a chance post some pics...we love pics!
     
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  3. k-moe

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

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    It's best to rebuild the master cylinder too.

    What I do to bleed the system.
    1. get a large syringe from a farm store and about a foot of vinyl tubing (you can also use a 2-stroke oil mixing syringe).

    2. Cut 6" of tubing and attach that to the end of the syringe. Remove the Syringe plunger. You now have a funnel to fill the master cylinder with.

    3. Break loose all four bleed fittings (be sure to put down cat litter or drip pans).

    4. Tie the brake lever to the grip.

    5. Fill the master cylinder and syringe.

    6. Wait overnight (or at least a few hours)

    7. You should now see brake fluid coming out. Close the bleeders, and untie the brake lever.

    8. Bleed the brakes as normal, starting with the anti-dive bleeders, then the brake caliperbleeders. Remove the funnel.

    9. You aren't done yet. There will still be some air in the system. The next step cures that, no matter what method you use to fill and bleed the system.

    10. Use a vibratory sander (no sanding pad) and slowly run it along the brake lines, calipers, and distribution block from bottom to top. This will move any remaining air bubbles up into the master cylinder. Tap (or vibrate) the master cylinder to get the air bubbles to come out of the return hole. This process can also be done with a box-end wrench or other similar tool, and tapping the calipers and lines (it just takes longer).

    11. Do one final bleed normally, just to be certain that the calipers are fully bled.

    12. Use a flashlight to check the fuid level in the master cylinder. It should be below the fill neck. Unfortunately there is no dip-stick or sight glass on this master cylinder, so unless you empty it and measure out the fluid you will need to just eyeball it. If the fluid level is too high the brakes can hydrolock and not release.
     
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  4. joeseca

    joeseca New Member

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    thank you both very much for the feedback.

    remarkably, after sitting for 12 years ( not the 15 years that the PO stated, but what"s the difference, right ?), there was fluid in the master cylinder reservoir and it was not at all crusty.

    so, are you saying that opening the system, tying off the brake lever and waiting for a few hours/overnight will (hopefully) get fluid flowing through on it's own ?

    also, am i correct in thinking that the black, plastic, frame mounted part is nothing more than the reservoir and that the master is downstream operated by the cable ? i have never seen this before so i just want to clarify.

    lastly ... pics ... it's really not much to look at but i know pics are always welcome; will get a couple up later today.

    thanks
    joe
     
    Last edited: May 31, 2019
  5. k-moe

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

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    The master cylinder is directly below the fluid reservoir, which is mounted to it. Both are mounted to a plate that mounts to the triple tree. The cable does operate the master.

    Opening the eystem and tying the lever back will allow brake fluid to flow down the system, unless the master cylinder has a bunch of crap in it. The seals age out, and it's rare that anyone ever really cleans out all of the old brake fluid and the accompanying goop that forms as water vapor seeps in. For all you know what is in the master cylinder was added just prior to the sale.

    You can't post any pics or links until your fifth post. It's the most effective anti-spam measure we have come across.
     
  6. joeseca

    joeseca New Member

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    here's where i am at now ...

    opened all 4 bleeders, tied back the brake lever and left it overnight. not a drop of fluid flowed through. squeezed the brake lever ... nada. after removing one of the bleeders completely i could see some fluid just barely pulsing in that bore as i pumped the lever. no action whatosever anywhere else.

    my goal with this bike is to resurrect, not restore. with that in mind, and the fact that rebuild kits are somewhat pricey (exchange on canadian dollar and shipping), and the obvious inaccessibility of these components ... should i be thinking of changing to a conventional master cylinder set up ?
     
  7. k-moe

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

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    A conventinal master cylinder is a good option if you aren't interested in a restoration.
    The bore size is 17.46mm, so keep the replacement as close to that as possible (16mm works well). You will have to change handlebars also, as the stock bars have tabs that hold the rubber shrouds in place, which look unsightly with the shrouds removed. Don't cut the shrouds as they are getting difficult to find and can fetch decent money (or can be saved for later should you decide to restore).
    EMGO makes a good variety of bars at a reasonable price. I have their Classic bars on my Seca. Others prefer the Daytona bar.
     
    Last edited: Jun 1, 2019
  8. joeseca

    joeseca New Member

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    i see what you mean about the tabs.
    fortunately, i have a couple of sets of honda handlebars (pardon the blasphemy) that should work.
    when you mentioned that the shrouds would be worth money you got my attention. ran out to check but i think seca shrouds 001.jpg the PO may have carved it up . it's like this on both sides. doesn't look factory to me.
    found the time to get it running today. it's smoking pretty bad but that could just be sticky rings ... at least, that is what i am hoping for. it revs up with gusto and even idles on it's own, albeit poorly. electrical all works but haven't checked charging system yet.
    really like the warning system on this bike.
     
  9. Timbox

    Timbox Well-Known Member

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    If you are careful with the calipers, you can take everything apart and clean them up. If there is not fluid leaking all over the place now, a good chance you can clean them and safe the "O" rings for the puck.

    You could remove one of the brake lines coming down the the "T" connector and see if you have a good flow from the line. This would tell you if it was a blocked master cylinder or something to do with the calipers being all gummed up. Once I cleaned my system it was easy to bleed it compared to other bikes I have worked on.

    The cuts on the bar cover are stick. All the cables and wires that are on each side should be tucked under the rubber covers when it is buttoned up. That will be something you will have to look into if you are changing out the bars as well, how to cover and protect the wiring. I guess it does have a plastic black sheath on it you can just tie wrap.
     
  10. k-moe

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

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    The bar shrouds can do that. The foam breaks down and causes the rubberized cover to split or deform. While a whole set can fetch decent money, it's not so much that you should feel bad about yours being damaged. Liiks like they are just tweaked a little though, and not coming back to meet at the split. You might be able to use a little heat to get them to reform back so the hole for he control cables mates up at the factory split.

    The controls and wires are lashed to the bars with the usual straps, so keeping them in place won't be a problem unless the OEM straps are missing or damaged.
     
  11. joeseca

    joeseca New Member

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    here's where i am at with this bike now ...

    definitely needs a master cylinder. IF the resurrection continues i will go the way of swapping it for a more conventional system.
    smoking problem GREATLY reduced, but still some visible smoke when the engine gets warm.
    engine starts readily, idles and revs quite well considering i have done nothing to the carbs other than drain old gas.
    a few around-the-block test rides (only the rear brake works) have revealed that the tranny is difficult to shift from 1 - 2, almost impossible to shift 2-3.
    tires and battery are, of course, complete garbage.

    not sure what to do with this bike; the cost of a resurrection would likely exceed it's value, but i hate to let it go because there's a lot to like about these bikes.
    probably going to push it down the side of the house until a donor/donee shows up.

    to be continued (i hope) ...
     
  12. Timbox

    Timbox Well-Known Member

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    Most of these older bikes are a bobby and passion for use the have them. The love of resurrection is all part of the adventure of these gems.
    https://www.xjbikes.com/forums/threads/tech-topic-the-real-costs-of-maintenance.14581/
    You have to be willing to put some money back into these bikes to get them running and road safe. If you are unhappy with the bike I am sure it will sell and you will be able to find something that is more suited to you. I hope that you will continue to read up on how to do the work and get her back on the road yourself.
     
  13. k-moe

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

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    My thought about cosmetics are as follows:
    Can you see it while you're riding? NO? Leave it alone except to deal with rust.

    The transmission problem could be one of three things.

    1. clutch cable is stretched or in need of adjustment (or both).
    Clutch Adjustment & Clutch Cable Replacement Procedure

    2. Clutch plates sticking from sitting for so long. The best remedy is to replace with new.
    CLUTCHES 101-Part 1: the 400/550/600s with pics (the 750 clutch is similar, and the differences are pointed out in the thread).


    3. Broken alternator chain guide (one of two annoying problems the the shaft-driven XJs have).
    Checking for a broken guide is pretty simple, but replacing the guide is time consuming since the cases have to be split. If you find a broken guide plan on rebuilding the starter clutch while the engine is apart.
    emergency_guidectomy

    The above is a temporary measure, as the alternator chain is free to contact the inside of the engine case without the guide.

    As for value: I always compare my cost of refurbishemnt to what a similar new machine would cost me (all used bikes need work done to them).
    I cannot come close to buying a new bike for what I have into my XJ. I can't even buy a road-ready used bike for the cost of refurbishment.


    [EDIT] There is a fourth thing that could be the cause of the shifting trouble; bent shifting forks. That is the least likely problem. Odds are that the clutch cable is the cause.
     
  14. joeseca

    joeseca New Member

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    thanks everyone for the feedback.
    to me, the biggest issue is the shifting problem. i seem to be getting good action out of the clutch lever but will look into that a bit further along with the possibility of sticking clutch plates.
    i never expect to make much money on a resurrection; would be far more profitable to work for minimum wage than to fix and flip these oldies. if i can make a bike roadworthy, ride it a while and then recoup my investment when i sell it then i'm fine. i enjoy the challenge of the resurrection and enjoy getting to ride different bikes, essentially for free.
     
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