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GT250 X7 Performance Mods

Discussion in 'Suzuki 250cc 2 Strokes' started by Jock, Aug 27, 2014.

  1. Jock

    Jock Member

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    Hey Fellas
    Im new on here and Ive had a '79 x7.
    Ive ordered a new custom harness, it had new pistons, rods, bearing etc.\
    But I want to go fast..... Really Fast!
    Whats the best way to improve power and performance?
    I have a super helpful mate with a bike dyno in town so we can get some proper figures
    Let me know what you think.
    Cheers
    Jock
     
  2. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    Full exhaust system + re jetting ? That's how it's usually done...
     
  3. Jock

    Jock Member

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    Yeh Righto. Whats the best way about exhausts. I don't know what to do with expansion chambers etc
     
  4. kiffsta

    kiffsta Administrator Staff Member Dirty Wheel Club Contributing Member

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    Hey Jock

    Welcome to the fourm, Phil has his GT250X7 X7 in my Garage, Im down in Brisbane.

    I too looked into this, higgspeed make some chambers for the X7, check them out here :

    http://www.higgspeed.com/-SUZUKI-X7-250-PIPES



    Does your have spoke wheels or mags?

    Cheers

    Chris
     
  5. Jock

    Jock Member

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    Hey Mate
    Ive got the mag wheels. Ill need new tyres as well.... Ill just add that to the list of stuff I've gotta do
     
  6. Mclaren

    Mclaren Well-Known Member Contributing Member

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    Bore the motor out
     
  7. Jock

    Jock Member

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    yeh righto. What size do you bore it out to. Ive also heard that port work can give good gains
     
  8. Mclaren

    Mclaren Well-Known Member Contributing Member

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    Depend on wall thickness and internals but porting can def increase power stops restrictions by that I mean it flows better
     
  9. Murdo

    Murdo The Good Doctor Staff Member Premium Member Ride and Events Crew Contributing Member

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    Hi Jock and welcome.
    Porting a two stroke barrel is not something that you just 'hack' into with a big file. You need to establish what you want to do, and plan towards that (street rider/track/racing?).
    My suggestion would be to thoroughly go over what has been done to check it is all in tip top condition and to specs. Then look to the chambers, bigger carbs (properly tuned with a decent air box, NOT them stupid pod filters), ignition set up, porting work (and matching/blueprinting all ports/cases) and a bigger tank to keep the fuel up to it. Overboring is not such a good idea on two strokes, better to get barrels resleeved, cases bored to suit etc, maybe look for some 350cc barrels.
    Plan what you want, and enjoy the ride.
     
  10. Scotchy

    Scotchy Active Member

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    boring out and putting cast sleeves is no good on engine that were designed to have chrome bores. The thick cast is too much to cool with the little water jackets designed for thin chrome bores. I have a fresh engine with brand new Suzuki pistons that nips up within 5 mins of running. Sent it to wiseco and it came back with cast liners.
     
  11. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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  12. Brizfox

    Brizfox Well-Known Member Premium Member Contributing Member

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    When I was a 19 or 20 something youth back in Blighty I bought one of these and it had already been tuned by a bloke named Harry Barlow. It was quick, 110 mph on the motor way one afternoon with my mate in his Ford Capri 3 ltr sport clocking me.
    Anyway I think from memory it had cross over expansion chambers, 2 base gaskets to raise the exhaust port, no head gasket and bigger jets and may have had Boysen reeds.
    Back in the day the most common way to increase the peakyness of the motor was to raise the exhaust port by a mm . and to widen the intake ports a bit at a time, bit slow but thats how you didi it.Im sure there has to be some notes some where on the net about these things.
     
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  13. tintankaussie

    tintankaussie Well-Known Member

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    I have 5 two strokes the one i just finnished is a kawasaki 100cc g7 two stroke,this bike was a donation so i part restored it.
    In my research on the net look up graham bell two stroke tuning,he covers every aspect of racing and prep work.I followed his guide-lines to the "T" and boy does it go scary
     
  14. Nathan Oliver

    Nathan Oliver Member

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    Hey matey, I noticed you were from Toowoomba, I sent mine down to BRM in murphys creek for some porting work. Also are you going to big chill at all ? I'd like to have a look at yours
     
  15. Brizfox

    Brizfox Well-Known Member Premium Member Contributing Member

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    Have you got a contact number for BRM.
     
  16. Mclaren

    Mclaren Well-Known Member Contributing Member

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    Called google mark lol
    tel:+61434375696
     

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