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Radian 600 engine into an Xj600 frame?

Discussion in 'XJ Technical Chat' started by mark1911, Mar 31, 2020.

  1. mark1911

    mark1911 Member

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    Am having some trouble putting an 84 Xj600 engine back together. I was wondering could I just put an earlier radian 600 into an Xj600 84 frame or would there be problems with this? I know earlier models of the xj like mine have brushes and different pick ups on the alternator compared to later models. Seen a radian engine that looks similar the type that has 4 four screws on the left side of the engine and not the Allen bolt type apart on later models apart from that was there anything on the earlier radian 600s that were different or could they be just a straight swap.
     
  2. bensalf

    bensalf Well-Known Member

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    they appear to be a straight swop, if as you say ,you can get the earlier generator type. the radian ,though, was de-tuned to 52 bhp your xj would be nearer 70 bhp
    stu
     
  3. a100man

    a100man Well-Known Member

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    You'll probably need the TCI too and may have to make some wiring swaps to interface to it.

    Early XJ600s will also have the lower power motor, if you swap for a later Radian (crank end alternator) then you probably end up with a higher power than before.

    the power output of the 600s seems to be subject to a lot of conjecture.. e.g how on earth did they squeeze an extra 20 horse from it over teh course of 5 years
     
    Last edited: Apr 1, 2020
  4. a100man

    a100man Well-Known Member

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    oh yes and teh later motors ran BS32 carbs....
     
  5. Simmy

    Simmy Well-Known Member

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    I think my 88 FZ600 is down a couple of horses from the XJ/FJ on account of carbs being BS30 vs BS32. The Radian got BS30 to.
    I don’t believe there was any significant differences in the motors of the three bikes. I put an FZ motor in a girlfriend’s FJ many years ago. A guy warned me that the drive sprocket is aligned further out on the FZ. We didn’t notice and she sold the bike shortly after. Never confirmed if this is true for any of them.
     
  6. Simmy

    Simmy Well-Known Member

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    I did have to stick with the FJ pick up coils and timing plate.
    I don’t know anything about the later FJ bulging ignition but agree best to use a matching TCI
     
  7. mark1911

    mark1911 Member

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    So would I need the radian/fz 600carbs as well from an earlier radian/fz600 engine and or different carb to head rubbers.
     
  8. Simmy

    Simmy Well-Known Member

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    just transfer your existing carbs and intake rubbers over to the new motor. Pick up coils and timing rotor plate to.
     
  9. Simmy

    Simmy Well-Known Member

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    I just looked at various part numbers and this interesting:

    The Radian has different intake cam shaft than the FZ and XJ/FJ so it might be biased for grunt vs top end.
    The Radian, XJ550 and FJ600 all use the same transmission output shaft assembly. The FZ is different.
     
  10. bensalf

    bensalf Well-Known Member

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    by the way , what is the problem with the original xj motor
    stu
     
  11. mark1911

    mark1911 Member

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    Problems with the gear box assembly basically the shift shaft t assembly lever keeps popping out from behind the selector drum. It looks like I've got everything correct though I obviously havent. Problems with timing the top end as well not sure if I've got it correct as it's my 1st attempt. It's took so long to get to this point with it buying tools gaskets cdi etc I thought it would be maybe quicker to just get an older engine from the same era and put it in but in the replies on here it could be I have more issues in going in that direction.
     

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