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Performance upgrades for XJ550 seca?

Discussion in 'XJ Technical Chat' started by Spokes81, Jul 14, 2007.

  1. Spokes81

    Spokes81 Member

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    Anybody know of any good performance upgrades for my 1981 XJ550 seca besides buying an XJ1100. I wan't to turn one of mine into a drag bike to see what i can get out of it.
     
    Spokes81, Jul 14, 2007
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  2. gitarzan

    gitarzan Member

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    You can change the Sprockets for a little more oomph at the low end.
     
    gitarzan, Jul 14, 2007
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  3. dinoracer

    dinoracer Member

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    For somewhat cheap, get some FJ 600 carbs and an aftermarket exhaust with air filters. The FJ carbs are two MM's larger. For more fun and expense get a FJ 600 engine and use that. You can order a Wiesco 652 kit for the 600 engine and have the top end balanced. While you have your cylinders out for boring have someone put a 3 angle valve job and port the heck out of your heads. I did that about 12 years ago and I was able to run 11.6 in the quarter mile, and that was with roadrace gearing for Willow Springs:)
    For aftermarket exhaust I have used Yosh and had the best peformance from that. .I had to get another pipe after the 4 to 1 collecter was all cracked up. I wound up using a Spec 2 exhuast. If I remember correctly I had to leave my bike with him so he could make one for it. It was nicely tucked, put out great power and weighed tons less than the stock exhast.

    Sean
     
    dinoracer, Jul 15, 2007
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