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How do I tell if I have an original from brake MC?

Discussion in 'XJ Technical Chat' started by JPaganel, Sep 14, 2018.

  1. JPaganel

    JPaganel Well-Known Member

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    I've put up with crappy brake performance on my 550 Seca for as long as I have owned it.

    The lever is stiff, no air bubbles, nothing is sticking. Nevertheless, it takes a serious grab to make it work.

    Since the bike was a basket case when I got it (front brake was the only thing that actually worked), I wonder if the previous "handy" owner didn't swap out the MC for another one with a bigger bore.

    So, how would I know this? I don't remember MCs having part numbers stamped on them.
     
  2. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    NOTE: before ordering your master cylinder rebuild parts, please take a moment to inspect and confirm that your bike does indeed have a factory original (for your model) master cylinder on it. After all these years….and so many previous owners…...there’s no telling what’s resting up there on your handlebars, and since rebuild parts are quite specific designed to work only with a particular style master cylinder ----- well, it’s best to be safe than sorry!

    So here are the clues for original master cylinder identification:

    XJ550 all North American models: the cylinder body will have the size 1/2 and the word NISSIN cast into it along the larger rear facing side of the cylinder body. Original (1981-83) cylinders will have the word NISSIN in all capital, block-style letters, while later “replacement” cylinders will have the word NISSIN appear as a stylized semi-script, with the two “s” letters layered on top of each other. Both types will accept all of the parts that we have listed below as fitting original master cylinders.

    XJ550 non-North American models (dual-disc bikes): the cylinder body will have the word NISSIN cast into it along the larger rear facing side of the cylinder body, and have the size 5/8 cast into the forward face of the cylinder body just to the left of the fluid outlet port (where the brake line attaches).

    1984-85 FJ600 and all XJ900 F, N, and FN models: the cylinder body will have the size 5/8 cast into large front face side of the cylinder body just above the fluid outlet port (where the brake line attaches), and the manufacturer name does not appear anywhere on the cylinder body.

    XJ600 Seca II models: the cylinder body will have the size 14 (meaning a 14mm bore) cast into large front face side of the cylinder body, and the manufacturer name does not appear anywhere on the cylinder body.

    XJ650 Maxim and Midnight Maxim North American models (single-disc): the cylinder body will have the size 14 (meaning a 14mm bore) and the word NISSIN cast into it along the rear face of the piston bore. Also note that these cylinder bodies have a "tilted orientation" to compensate for their "angled" handlebars.

    XJ650 non-North American (dual disc) models, XJ650RJ Seca, all XJ700, XJ750-X, XJ750RL, and XJ900RK and RL models: the cylinder body will have the word NISSIN cast into it along the larger rear facing side of the cylinder body, and have the size 5/8 cast into the forward face of the cylinder body just to the left of the fluid outlet port (where the brake line attaches).

    XJ650 Turbo, 1982-83 XJ750 Maxim and Midnight Maxim, and all XJ750 Police models: the master cylinder body will have the size 5/8 cast into it along the larger rear facing side of the cylinder body, and the word NISSIN does not appear anywhere on the cylinder body. The XJ650 Turbo, 1982 XJ750 Maxim, and XJ750P master cylinders have a small (1/4” diameter) hole in the base of the reservoir where the fluid level sensor wires exit the inside of the reservoir. Also note that both the 1982 and 1983 XJ750 Maxim/Midnight Maxim model cylinder bodies have a "tilted orientation" to compensate for their "angled" handlebars.

    XJ750 Seca and all XJ750 Euro models: the long skinny cylinder body will have the size 11/16 (meaning a 17.5mm bore) cast into it along on side the piston bore, and the word NISSIN does not appear anywhere on the cylinder body. A good image of this type cylinder can be seen at: http://www.xjbikes.com/forums/threads/new-member-need-help-with-brakes.78654/#post-492845

    XJ1100 Maxim and Midnight Maxim models: the cylinder body will have the size 14 (meaning a 14mm bore) cast into it along the rear face of the piston bore, and the word NISSIN does not appear anywhere on the cylinder body. The bottom of the reservoir has a small (1/4” diameter) hole in where the fluid level sensor wires exit the inside of the reservoir. Also note that these cylinder bodies have a "tilted orientation" to compensate for their "angled" handlebars.
     
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  3. JPaganel

    JPaganel Well-Known Member

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    I have that, so it's original.

    Dang. No easy solutions...
     
  4. Xjrider92117

    Xjrider92117 Active Member

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    Do you have single or dual disk? Just curious. I have a single. If I want to stop, somewhat quickly, it always takes a handful to do so.
     
  5. Polock

    Polock Well-Known Member

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    my suzuki has two finger brakes and i don't really like them
     
  6. k-moe

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

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    The XJ loves compression braking. Standard practice when the bikes were made.
    If you're comparing the brakes to anything made in the past 20 years, you'll be disappointed.
     
  7. JPaganel

    JPaganel Well-Known Member

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    I'm in the US. So, it's a single disk.

    Dual disks would be great. I wonder if Radian forks would be a direct swap... The wheel does have screw holes for disks on both sides.
     
  8. Xjrider92117

    Xjrider92117 Active Member

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  9. jayrodoh

    jayrodoh YimYam Premium Member

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    What you need to look at is the bore size on the MC. If you have a single disc and the MC is from a double disc bike, you will have a stiff lever and poor braking. If it says 1/2 on it, that is the correct one. If it says 5/8 then someone swapped it out with a dual disc MC.
     
  10. JeffK

    JeffK Well-Known Member

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    FWIW, I have stock dual brakes on my '82 Turbo and the stock brakes even after being rebuilt/hoses replaced during the restoration are actually WORSE than either of my stock H2's! "Wooden" is an apt description!!

    Being compared to a Widowmakers brakes is not a compliment, not in the least!

    jeff
     

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