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XJ550 Maxim "factory" cam upgrades

Discussion in 'XJ Modifications' started by Raunchtastic, Feb 21, 2019.

  1. Raunchtastic

    Raunchtastic New Member

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    Hello, all!
    I've got an '82 XJ550 that I'm finally getting around to doing something with. its got about 14k miles on it, so it sat for a long time. I have ridden it on and off for the last 10 years doing small maintenance things that I could afford or felt competent enough to do myself, then had kids and parked the bike.
    Over this winter I've decided to really turn it into what I have always wanted it to be: a cool, fun bike and a conversation starter. I dont care about being the fastest, the loudest, etc. Ill be completely transparent and say that in this endeavor, I am merely chasing sound.

    I have been looking into swapping out the cams (which I understand is a crapshoot for reliability). I had read in another forum post that the FJ600 cams will physically fit, and require an electric tach to be installed, which I am fine with. My question is if the '92+ models will also fit, i.e. Seca II cams. I found a reasonably priced set of cams, but don't want to throw money at it if it wont work for my application.

    Should I run into problems with an engine failure, I may go the route of swapping an entire FJ600 driveline in, but again, I'm chasing the sound, not so much the power. I certainly plan on re-jetting the carbs after any work. Let me know what information you can share with me, thanks!

    **edit**

    I should also add that I have already taken the time to do as much maintenance as I've felt the bike needed: rebuild the caliper, new brake line & pads, rebuild the front forks, rewired the fusebox, cleaned the gas tank, oil change, new tires, etc. I will be making sure the bike is 100% safe in stock form before any major changes.
     
    Last edited: Feb 21, 2019
  2. a100man

    a100man Well-Known Member

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    Hmm, I doubt teh Seca2 (Diversion) cams will fit - the motors are quite different. Earlier FJ/XJ in EU is a differnt matter, and yes you can swap teh etire engine (also FZ600)but that wuill alos require some ancillaries such as carbs and TCI (ignitor box). Mikuni BS30 carbs are physically the same size as BS28s (550 standard) and those are what you should be aiming for rather than the bigger BS32s which are a struggle to fit.

    I have in mind that a fun engine build would be to use 550 (528) barrels bored to take 600 (598)pistons plus a 600 head and BS30 carbs - capacity would be
    around 560 (I did the maths once) - using the whole head would be easier I think (no blanks tacho drive) bore matched to size etc.. It is also a trodden path (not yet by me but I have the parts ready!)

    Good luck
     
  3. Raunchtastic

    Raunchtastic New Member

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    I ended up finding a set of FZ600 cams at a fair price and ended up going that route.
    The forum seems to think I am spam, so my reply is cut short.

    Can I use stock intake boots with the BS30 carbs?
     
  4. Thrasher

    Thrasher Member

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    No on the stock boots.
     
  5. a100man

    a100man Well-Known Member

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    It's been a while, I can't quite remember but I think the head intake boot are OK as it's only the ID not OD of teh carb thatis different (BS28 vs BS30) that is. The air box boot might be different though. Best check https://www.yamahapartshouse.com/oemparts/c/yamaha_motorcycle/parts for part number comparison.
     
  6. Raunchtastic

    Raunchtastic New Member

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    Thats good to know.

    My coworker used to race an FJ600 when these bikes were new, so he has been guiding me to the best of his ability, but he never played around with the 550s. He has been trying to convince me to just swap the 600 in, but I would feel like I'm wasting the 550 engine at that point.

    As far as exhaust, I'm still running the original setup, and haven't had a ton of luck finding good 4-1 aftermarket. The air box is long gone, and I have no intentions of putting stock parts back on if I can help it, haha.
     
  7. Polock

    Polock Well-Known Member

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    i'm with your co-worker on that one. you might be wasting the 550 but you might be killing it too
     
  8. a100man

    a100man Well-Known Member

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    This is a good point.. In the 'fun build' scenario the rebore will probably cost as much as a used 600 motor.. Depends on how much time you want to invest in the project and availability of parts. FWIW I have a 600 motor in my 550 but it took a few goes to find a 'good' one. A14k 550 might not be the best start point given the low mileage.
     
  9. Raunchtastic

    Raunchtastic New Member

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    Well, I opened a few doors for myself. I found a semi-local 600 radian and jumped on it. With a title it was $375 all there, I was able to turn it over with a battery and it sounded healthy, no knocks, metal on metal grinding or other unnatural noises. Forks felt tight, definite cosmetic issues, but otherwise solid. It has a D&D exhaust that I'll be swapping onto the 550. I bought the 600 for a friend, as he has had some bad luck, is going through a divorce, and hasn't had a bike for about a year. I figure I'll throw the 550 exhaust on it, assuming it all fits well, and when he gets back on his feet and buys a bike more to his style (he likes the cruisers) I'll repossess the 600, haha.
     
  10. a100man

    a100man Well-Known Member

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    Result.. BTW the sexy box-section Radian swing arm bolts straight on to a 550 ;-)
     
  11. 50gary

    50gary Member

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    Ride the Radian.

    Cheers, 50gary
     
  12. a100man

    a100man Well-Known Member

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    .. but not far, on that fuel tank.
     
  13. Raunchtastic

    Raunchtastic New Member

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    Maybe sometime down the road I will end up riding the Radian as well, but the combination of time/money I have very recently invested in the Maxim coupled with the intent of gifting the Radian to my buddy puts that off for at least a season or two. I keep hearing great things about the Radian, so some longer test rides are surely in order... for research purposes.
     
  14. a100man

    a100man Well-Known Member

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    Oh, did you say 'Maxim'.. In that case Gary's right - get on the Radian, your mate can have the Maxim after all he likes cruisers..
     
  15. Raunchtastic

    Raunchtastic New Member

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    Nah, the maxim has sentimental value, I couldn't sell it for the foreseeable future. I've come close a few times over the years, but could never bring myself to do it.
     
  16. Raunchtastic

    Raunchtastic New Member

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    figured I would throw an update. I put the 600 cams in the 550 and was able to get it to idle. I took it for a very short ride to the end of the street and back to get an idea of how lean it is. I have some larger jets coming this week, once I'm able to get it jetted well and running smooth I'll post up what sizes they are for future reference.

    I also gave the Radian to my buddy and he loves it. He is moving this month, so it is still sitting in my garage should I ever feel a test drive is necessary.

    Lastly, I convinced my coworker to buy an FJ600 a few weeks ago. It was a "project bike" that "only needs coils." The tci box was fried, confirmed by swapping the Radian box on and getting it to fire right up. He ordered a new box, so that should be getting some love over the next few weeks also.
     
  17. a100man

    a100man Well-Known Member

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    Update appreciated..:)
     
  18. Raunchtastic

    Raunchtastic New Member

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    I've got the bike running through the RPMs, but now it's a bit on the rich side. As of now, main jet is 122.5, pilot is 40, and I have 3 needle shims. I'm going to try with one less shim and see how it acts. I can ramp throttle in and get all the way without stumbling but any rapid throttle movements and it bogs for a second.
    As a reminder, I am running UNI pods, D&D 4-1 exhaust and Radian cams.
     
  19. Raunchtastic

    Raunchtastic New Member

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    Another update:
    I looked back and actually the cams I put in were FJ600 cams, not Radian cams. Not sure how I got that mixed up. I installed a wideband O2 sensor (had one laying around from another project) and watches the fuel through the gears a few times. At warm idle with the 40 pilot jet it sits right around 15:1 AFR, so im pretty haply with that. I took out all the needle shims except one and atill have 122.5 main jets and rolling into the throttle slowly you can watch the AFR dip down to 11:1-10:1 even dipping into the low 9:1 range under WOT. Clearly the main jet is too large. Hopefully I'll have some time to change it and get more time on the road. The bottom end pulls really strong until it starts getting stupid rich. I also took the time to check all the valve clearances and they were all just a bit tight, so I took care of that.
     
  20. Thrasher

    Thrasher Member

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    I am getting ready to install two intake cams from the FJ motor in my FJ motor. I have some cam sprockets that are index-able, with the help from a timing wheel and dial gauge.
     

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