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Recent content by gtrack45

  1. gtrack45

    Very short stroke 250cc single! Advise appreciated.

    thephantom, All a bit experimental but...4 valve, OHC, single cam, air cooled, methanol fuel, inlets: either 29, 30, 34 or 35. Exh: same sizes, prob go with 30 (mm) but depends on what choice of bore i use...either the 80 or the 85. port size and length unsure on, unmanifold length is in the...
  2. gtrack45

    Very short stroke 250cc single! Advise appreciated.

    djcramond, haven`t sorted the gearing side of things yet but would be looking around a band of 9000-11000 ish...although everything is a little sketchy at the moment to be honest!...
  3. gtrack45

    Very short stroke 250cc single! Advise appreciated.

    Fabrico..silly me!...now i get it...i thought you were thinking of a c/case turbo system..i saw something similar a while ago, think it was called a `six stroke`!!...seriously!...theres a web site on it somewhere. Never liked 2 strokes, never will but i do respect the huge power they can achieve...
  4. gtrack45

    Extreme bore stroke ratio

    dj, sounds interesting. Be good to hear from someone that has had hands on experience from beginning to end....what crank did you use and what weight did you opt for with the flywheels? Many thanks.
  5. gtrack45

    Very short stroke 250cc single! Advise appreciated.

    Fabrico, this sounds interesting as the flywheel weight was one area i am still unsure on. As far as i can make out there is no restriction on ports?? I can only use 1 carb and 1 exhaust (not that this would matter?)but it does say the engine has to be N.A with no forced induction?...now i know...
  6. gtrack45

    Extreme bore stroke ratio

    Thanks for the replies, sadly im restricted to a single due to the rules saying so! I knew the b/s ratio was tame compared to a multi, never gave dukes a thought...still a bit concerned that mines a single, think ill have to just build it up and find out i guess?? thephantom, good luck with the...
  7. gtrack45

    Very short stroke 250cc single! Advise appreciated.

    Fabrico, rules only allow single cylinder (mono) im afraid. Make more sense to do what everyone else is and mod one of the new moto x units, but thats just not me, i like to be different! Was hoping someone had some hands on experience with these type of b/s ratios on a single, i know they are...
  8. gtrack45

    Very short stroke 250cc single! Advise appreciated.

    Greg, it all seems to work out ``on paper`` Ive done a similar idea with a 350 but not with a smaller 250. Its going to be very peaky but with my theory gearing we should be ok. I was a bit worried with it only being a single cylinder, the only thing i have a few variables and doubts on are...
  9. gtrack45

    Very short stroke 250cc single! Advise appreciated.

    I am currently building a 250cc 4 stroke single which employs an extreme b/s ration of 1.6...b=80, s=50. Does anyone know of any practical probs im going to have in reality? im especially concerned with the cam timings, i have used a 165mm long con rod, it is 4 valve and on Methanol although due...
  10. gtrack45

    Extreme bore stroke ratio

    thephatom, hi...i am in a similar situation, i am building a short stroke 250cc single cylinder 4 stroke, it has a 80mm bore and 50mm stroke. How did/are you getting on with yours?..i was worried that the stroke and B/S ratio would be too extreme, but after reading what you are up too im...
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