Upgrade piston, camshaft and carburator for XR650L

Discussion in 'Thumpers' started by Dr LC8, Dec 30, 2010.

  1. mcma111

    mcma111 Long timer

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    Your correct with the 102.4mm piston with the OE sleeve.
    #61
  2. RichNX650boy

    RichNX650boy n00b

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    To Nic from Manchester / Roma .
    Hello to everyone I have just joined this excellent forum in London.
    Very interesting reading here all the various engine mods available .Love the 105mm piston, XR carb,idea.
    Nic First question.Where did you get your XR650L from? I was not aware that they were available in England.
    Did you have it imported from the States?
    2. Re:NX650 Dominator gear ratio modifications .I had a 1997 NX650 from new and sold it with only 8000 miles on it. I hated the overdrive 5th gear with the big gap down to 4th but maybe it works out on your XR650L bikes. .
    3 JE.10.5:1 piston,stage two White Bros cam , Jagg oil cooler ,Arrow straight through exhaust, stronger clutch springs, 42 rear aluminium sprocket, 15 front sprocket, carb mods,52 slow jet, 158 main, standard drilled out carb and dino jet needle. Drilled out air box etc. lowered 40mm front and rear although I am 5.11.
    4 It pulled like a train once it hit the cam at about 4000 rpm and could cruise at 80 all day at about 4000 to 4500 but I hated the big gap between 4th and overdrive 5th gear..
    5. I sold it because it was a top heavy moose of a bike(170kg /374lbs dry ) and I always wanted an XR650L with all the engine mods.
    6 I assume that I would have to import one.
    7 .Hey ,thanks for listening ,.Bye the way ,.the jagg oil cooler mounted at the side is essential even here in England in the summer to keep the oil temp down when cruising at 80 to 90 mph.Drops the temp by about 30 degree .


    #62
  3. RichNX650boy

    RichNX650boy n00b

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    To Cycle Wizzard or colleagues,
    How much heavier is a 105mm JE Piston than a 100mm Je piston? Just thinking about effect on revs but would not want any more that 5500 revs as would be a road bike .



    #63
  4. RichNX650boy

    RichNX650boy n00b

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    To Cycle Wizzard or colleagues,
    How much heavier is a 105mm JE Piston than a 100mm Je piston? Just thinking about effect on revs but would not want any more that 5500 revs as would be a road bike .
    Rich NX650boy.London.


    #64
  5. RichNX650boy

    RichNX650boy n00b

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    To Cycle Wizzard or colleagues,
    How much heavier is a 105mm JE Piston than a 100mm Je piston? Just thinking about effect on revs but would not want any more that 5500 revs as would be a road bike .
    Do you need to machine the engine casing or use a special sleeve for the 105mm piston.?
    Rich NX650boy.London.


    #65
  6. sark

    sark Been here awhile

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    "wider airbox air conduit"

    Is this de-snorkeling? Thanks
    #66
  7. Mobil1

    Mobil1 Long timer

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    De-snorkel and trim the lip around the opening down half way. Then trim the rib on the bottom of the seat , in front of the opening. The de-snorkel alone is still restricted by the tight clearances under the seat.
    #67
    JCool likes this.
  8. sark

    sark Been here awhile

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    Thanks very much for informing me.
    #68
  9. techforlife

    techforlife CDI REPAIR

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    103MM XR`s Only ceramic coated piston is going in this winter,,see what this does,,:clap


    Digging up old treads = priceless


    :imaposer


    B
    #69
  10. JCool

    JCool Long timer

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    Treads ? :imaposer What compression ?
    #70
  11. sark

    sark Been here awhile

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    I'm anxious to find out. I got passed by a minivan on my XR last summer.
    #71
  12. techforlife

    techforlife CDI REPAIR

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    :imaposer

    B
    #72
  13. Kawidad

    Kawidad Long timer

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    You're okay until a Prius takes you on a hill. :lol3
    #73
  14. mcma111

    mcma111 Long timer

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    10.1
    #74
  15. JCool

    JCool Long timer

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    10.1 is too low. Higher compression will do more than the bore increase.
    #75
  16. mcma111

    mcma111 Long timer

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    Sure. Tell me more.
    #76
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  17. sark

    sark Been here awhile

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    It's funny you say that because it happened on a steep hill in the Catskills.
    #77
  18. JCool

    JCool Long timer

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    Usually YOU are increasing both at the same time , so you aren't seeing which is providing the power increase.
    #78
  19. mcma111

    mcma111 Long timer

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    So going from a 100mm, 8.3 compression ratio to a 103mm, 10.1 isn't enough?

    I have one of these slugs in my daily driver. OE cam, Dave's Mods, Uni filter, XR600 muffler. It sure does a good job of pulling my LARGE ass around at ease. It is a HUGE improvement. HUGE!!!

    BTW... NO PINGING EITHER!!!
    #79
  20. JCool

    JCool Long timer

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    Wasn't Brian running the 11.25 JE before ? Everything equal , except for the piston change , he'll be down on power.
    #80