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82 seca 550 front end swap to dual rotors?

Discussion in 'XJ Modifications' started by cavi, Dec 17, 2008.

  1. cavi

    cavi Member

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    what is needded to do the swap from a 650 with dual calipers to my seca 550 1982? What are the doable donar bikes and what do I need? Forks, tripples, wheel and calipers?
     
  2. taildragger

    taildragger Member

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    First what is the Seca 550 stock tube diameter and length? Measure this first. Unless I'm mistaken the Seca 550 uses 35 mm diam. tubes (1.375 inches).

    Then I'd start looking at Yamaha XS '80-82 forks as most came with slotted dual discs standard. Plus these forks are more rigid = less flex. You could look at transplanting an entire xs850 G Standard front end e.g. using the stock XS triple tree, fork sliders, calipers, discs; the works. Most likely the XS850 forks will have to be either clamped higher in the triple clamps or get trimmed to match the Seca's fork tube length. Make sure you measure the fork tubes for both bikes first. That is, if you want "no surprises" handling.

    As for using the Seca's oem front wheel with other Yamaha forks, I'm not sure. Again, measuring will help here. I have seen Virago spiral type rims used on XS frames.

    Finally, you'll get much better braking response, "clamping power" by installing dual stainless steel hoses and a Cafe Master Cylinder designed for dual calipers (dual brake systems need the extra fluid volume). I used a pair of Goodrich hoses on my xs850 Kruiser project. Even riding two-up the bike stopped like it had been dropped into a sandbank.

    I believe bigfitz has crossover tech / build data available on the Secas and possibly other Yamaha models.

    The oem XS dual brake system is quite powerful and would be a cost effective and significant upgrade for the lighter 550.
     
  3. cavi

    cavi Member

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    what about using the front end from a xj750 as they are easy to find and the forks are 36mm so they would be larger than the 35 that I have now?
     
  4. taildragger

    taildragger Member

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    Since the xj bikes have similar handling profiles that might be a good idea. Go for the whole enchilada - a full front end transplant.

    Depends on how fast you and your wallet wanna go. Don't forget, you'll be adding another 30 lbs or so to your bike.
     
  5. cavi

    cavi Member

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    hadden't thought about that....
     
  6. cavi

    cavi Member

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    who is bigfitz? I would love to see tha crossover data
     
  7. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    The 550 Seca uses an "under the tube" front axle mounting point, whereas all the XJ750 models use a "leading/in front of" axle mounting point. This change in axle location affects steering, braking, etc. in ways that may or may not be to your liking, or safe!

    The "rake" of the frame steering tube ("neck", or headpipe as Yamaha calls it) was designed with such an axle orientation in mind.

    The XJ650RJ Seca and the XJ650LJ/LK Seca Turbo tubes have the same "under the tube" orientation as the 550 Seca does, so they would be the most likely possible donors. Other issues will also have to be taken into account, steering crown intechange (will your stock handlebars fit the other model steering crown, etc.).

    The rest-of-the-world (non-North American) XJ550 models all used dual front disc brakes from the factory, and their fork systems should be a direct bolt-in replacement for your system. Unfortunately, you'll have to find a complete front end from such models in the UK or Australia/New Zealand (that's where the biggest sales of such models occurred) and then have them shipped over, which can get kinda pricey ($100+). BUT, it may be "the" way to go in the long run. Dual front disc brakes sure are nice to have..............
     
  8. cavi

    cavi Member

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    well I ordered a full setup off a 650 turbo minus the front wheel as it is ugly, I did get a wheel off a seca 650 non turbo, I imagine it should fit, hopefully anyway.
     
  9. dinoracer

    dinoracer Member

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    If you can find a FZ 600 front end you can use that also. Just use a larger dia front rim instead of the FZ's 16 incher. I think I used the front rim from either the FJ 600 or the vision 550 front rim. LOL now I have to go out and check..I will take pictures since it's been requested before but it's pretty dusty!!! Also if you wanted to use the stock 550 front rim you can. Just pop off the plastic cover that is covering the other holes on the opposite side of the rim and get a rotor and voilla, a stock looking dual disk setup for the seca 550.

    Sean
     
  10. cavi

    cavi Member

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    oh that is good to know, I might just use my stock rim, even though I like the look of the rim I bought, they also had the rear, but I do not think it would work as it was shaft drove and mine is chain, am I wrong? Will a shaft drive wheel work?
     
  11. dinoracer

    dinoracer Member

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    Nope the shaft drive rear wheel will not work for the seca 550, it must be a chain drive setup. Completely different style of hubs. I did manage to upload some pics into my gallery but it might take a day for them to get approved. That poor bike hasnt moved since I bought my house almost 5 years ago.. Lots of dust on her now and I really should start getting her back to street legal form. Get rid of that silly fairing that is on there now and find the stock bodywork!!! Bet that motor will still lift the front wheel up tho :) ROFLMAO gotta put a back one on there first.. Cavi where do you live, I might have a spare rear rim if you need one.


    Sean
     
  12. cavi

    cavi Member

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    I am in northern cal in Red Bluff about 2 hours north of sacramento,
    thanks for the offer on the rim, but I did already buy one on ebay so I sould be set.
     
  13. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Me but I can't take credit for the "front fork crossover guide" that was another member. However, chacal is right, the absolute BESTEST way to do it would be to get Aus or Euro market parts as those came with dual discs. All you need is the left fork leg and caliper, the wheel is as Sean described the bolt holes are there. I was going to do the dual disc conversion but decided to upgrade the existing brake with an EBC floating drilled rotor and ss lines.
     
  14. cavi

    cavi Member

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    okay, but do you have a general file on what fits from one model to another other than just fork swaps?
     
  15. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    No but I believe that info is on a thing called the "XJCD" and there's a link on ordering it on this forum. Personally, I'm working on figuring out how to do wire wheels "correctly" using Yamaha parts.
     
  16. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Sorry I just realized what Taildragger was referring to. You can use the Yamaha parts fiche to run a part number back through their system and see what bikes it's used on. It's limitation is its by PART NUMBER. There are some parts that are identical except for say, color, but since they carry different part numbers they don't cross. I use this fiche rather than the "official" Yamaha site because the diagrams are bigger: http://www.babbittsonline.com/pages/par ... fault.aspx Look up your part number in "Look up by model fit" and then copy/paste it into "quick lookup" and you'll get the aforementioned list.
     
  17. cavi

    cavi Member

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    okay, looking at pictures of the 82 maximum 550 front end it looks identical to the seca, the wheel mounts at the bottom of the fork, not behind the fork like larger models. Are the forks the same length, as I am going to try and find a euro set of forks and I might find a maximum set before a seca set.
     
  18. cavi

    cavi Member

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    I might be able to get a set of forks from england, can anyone tell me that they are the same diameter and length as the usa version for the 550 seca 1982, I ask as there will be a decent outlay of money on a set of forks that are in shi# shape, I will really only use the outter tubes
     
  19. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Should be. The "rest-of-the-world" models (with the dual discs) use the same chrome upper (inner) tubes as the North American single-disc bike. I would bet (but don't have a parts books to confirm for sure) that ALL the fork parts for the Euro models are identical, save for that single left-side lower (outer) fork tube, which has provisions for the left-side caliper mounting.
     
  20. cavi

    cavi Member

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    thanks, I will keep posted if I manage to get them
     

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