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  1. #1

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    GP1300R Bored EFI from 40 mm to 42mm

    I noticed this on ebay, but missed the final bidding

    Has this been tried and proven as I've seen a few post mentioning this mod. ie do the 1300s need bigger bored throttle bodies with mild states of tune (VF3 reeds, heads, key way but no porting)?

    Or is this a mod for ported engines only?

    Also I guess is the R&D/Riva and stock injectors up to the job for the increase air flow?

    A while back when I've put bigger carbs on 2 stroke bikes you tended to loose out on mid range but gain top end to a point when they were too big and then you just lost out.


    http://cgi.ebay.com/ebaymotors/ws/eB...m=120060831733
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  2. #2

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    I dont think anyone has tested it. I saw that too man they sold for some big cash.

  3. #3
    Happily Self-Employed WFO's Avatar
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    Quote Originally Posted by lvnspeed View Post
    I dont think anyone has tested it. I saw that too man they sold for some big cash.
    Honestly, it would cost you more than twice that to get them bored. You cant just bore them, you have to re-work the shaft bearings too because they get in the way when going larger.

    It seems the guy just gave it away.

  4. #4
    Mr Bill's Avatar
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    So why would he have "given it away" if it was worthwhile? Kind of makes you wonder.....

  5. #5
    Happily Self-Employed WFO's Avatar
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    Quote Originally Posted by Mr Bill View Post
    So why would he have "given it away" if it was worthwhile? Kind of makes you wonder.....
    Sure does.

  6. #6
    WATER WOODY's Avatar
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    I talked with the guy and he said noticable difference in bottom and mid pull along with more top speed but WHY dump them on E-Bay and just walk away? He only had 1 set,kinda made me wonder although i DID bid on them. He never answered my question about speed and rpm gains after i asked him twice.

  7. #7
    Yea i bid on them too, i was the guy who bud 259 with 7 seconds left and lost to 264... Dammit man! Im betting they would work best in the triple pipe rpm range.. 2mm over doesnt sound like as much as it really is when you do percentages of difference from 40 to 42mm.. Anyone remember the formula for finding that? Isnt pie involved in that? The 3.17 pie that is..

  8. #8
    Moderator RX951's Avatar
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    Quote Originally Posted by rossnemo View Post
    Yea i bid on them too, i was the guy who bud 259 with 7 seconds left and lost to 264... Dammit man! Im betting they would work best in the triple pipe rpm range.. 2mm over doesnt sound like as much as it really is when you do percentages of difference from 40 to 42mm.. Anyone remember the formula for finding that? Isnt pie involved in that? The 3.17 pie that is..

    The formula for finding the area of a circle is: pr² (p x r x r)

    pi = 3.14159

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