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Bit More Hp

Discussion in 'Supersport (1974-2007)' started by Carr01, Nov 16, 2019.

  1. Hi
    Has anyone managed to squeeze a little more Horse Power from their 900ss?
    Looking for subtle tweaks, if any.
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  2. Won't it be the usual airbox/ exhaust / ecu flash for 8? Seems a common theme!
  3. There is engine work that can be done too but return on investment would be negligible. Imho reducing weight gives better value.
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  4. never done anything more than a stage 2 dynojet kit, kn filter, upgraded coils and micron exhausts (on my old ss, current one standard) but there was a noticeable gain in power. not dyno'd but just before and after feel...
    not sure how id quantify the gain... 5%? 10%? dont know, but way better mid range and take off and obviously sound!!
    the only reason ive not done it to my current ss is ive not found any cans at the right price...
    ive heard some say removing or cutting the air box lid is beneficial but ive had a couple of mechanics who were involved in racing the ss tell me they didnt agree...
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  5. Less pies :):upyeah:
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  6. Very much pre ECU technology I’m afraid!
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  7. thats a good thing!!!
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  8. Ah so screwing around with jets and air screws!
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  9. Depends. All of the above.

    SS engines were a bit varied from one to the other so if you’re serious I’d (and did) start with improving the basics first.

    the heads are pretty pants out if the factory and so you’ll see the biggest gains for your money by first sorting that out.

    For bigger torque i went for bigger inlet valves as well and a set of high compression pistons.

    to refine the ride you’d then start looking at things like balancing components and dumping weight off that flywheel helps to allow it to spin up a lot quicker, as does a lightweight clutch basket. Both doable without splitting the cases- whereas balancing cranks/rods etc is case split job.

    the airbox frame mod is nice as its the preferred option to punching holes in the top of the airbox.

    Dynojet and slip ons work well for most in truth.

    you can go flatslides but be prepared to pay for dyno time to get them set up properly and keep a supply of float needles as they eat them like sweets.

    On the other end there’s the slip ons which are best for stock engines with a jet kit or the spaghetti systems and bora systems for higher states of tune.

    these old engines don’t respond as much to constant bore pipes unless you’ve got the tuning to match.

    big bore stuff means you eat away at the piston bore, which is bog roll thin anyway, and the 99x big bore kit you need to machine the cases which puts you quite close to the head studs.

    For all of that you’ll see about +15% hp with the big bore stuff adding dollops of torque.

    don’t forget electrical. A good set of coils will ensure spark is delivered consistently rather than weakening as load and heat increases.

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  10. A mate of mine managed almost 120 bhp out of his carby 900, quite an awesome tune up!
  11. do you know what he had done?
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  12. What did he do, stick an 1100 engine in there...!
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  13. Maybe an error crept in somewhere as does sound high for a hemi 2 valve 900. There once was a garage in London by the name of Elaborazione Colasuonno and it had a rolling road installed that got regular use with many "before" and "after" claims on Italian machinery. My mate Barry always called them Esagerazione Colasuonno.
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  14. I hear there’s one in the midlands and south west the same :p
  15. 120 bhp !!! Where was that measured, at the fuel tank?
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  16. I don't provide this service for everybody but as it's you Anthony i'll be sending up my slipstream in 2020 to help out.;)
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  17. You are one dirty boy Peter, dirty.
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  18. I'll be,time i fetch in some more oak wood today,i looked like shit yesterday covered with chainsaw chippings/mud etc.
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  19. Nice.
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