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What bike...

Discussion in 'Bike Reviews, Questions and Suggestions' at netrider.net.au started by [FLUX], Jun 20, 2008.

  1. ...would you start with? Here's a question for you all. I'm looking for suggestions on the best bike to start with in order to modify to reach the following goals:

    - At least 110hp (~82kW) at the rear wheel
    - Weigh no more than 150kgs with a full tank of juice
    - 4-stroke engine without needing to be tuned to within an inch of its life to achieve said performance
    - Sporting geometry. Naked is fine. Faired is fine.

    Am interested to hear your suggestions as to a good bike to begin modifying to achieve such.

    I'm starting to think that it can't be done, but am open to be corrected.
  2. I thought most of the Supersport bikes would get you in that ballpark.
    They're sitting around 110hp and a bit over 150kgs.

    The ZX6R is supposed to be 125 hp. Dry weight 167.

    Just keep ripping heavy bits off it. They add valves and servos to the exhaust to improve low end response. Take that off.

    They run the exhaust all the way under the bike then under the seat.
    Shorten that up. Replace the muffler with carbon fibre or something.

    Put a smaller fuel tank :)
    Possibly a 5 speed gearbox would be lighter than 6.
  3. Ignore manufacturer's stated dry figures. They are pure bunk. Most supersports sit in the ~185-190kg range with a full tank of fuel.

    It's a bit hard to pull a whole 40kgs off a Supersport bike, and herein lies the problem.

    In general you can do the following weight savings:

    4.0kgs - No fairings and fairing brackets & bolts
    1.5kgs - 520 chain and alloy sprocket conversion
    5.0kgs - Carbon fibre rims
    0.5kgs - Fender elimination
    8.0kgs - Full titanium exhaust system
    1.0kgs - Light-weight clipons and removing all bar weights
    0.5kgs - Replace all non-weight bearing steel bolts and screws with aluminium items
    1.0kgs - Headlight replacement
    0.5kgs - Pull off steering damper
    0.5kgs - Pillion pegs
    0.5kgs - passenger sub-frame reduction

    Even with all that, you're still looking at 23kgs weight reduction while still keeping it road legal.

    At best, we're still coming up 15kgs short.
  4. Umm... A CT110 with a 120 shot of nawwwwwwwwwz? :)

    *grins, ducks, runs!*
  5. I think your right.

    The closest I find in my wishlist:

    '08 990 Super Duke:

    118HP - I think.
  6. It also depends where the weight is... Some bikes are top heavy.
  7. Ill gladly be corrected, but the power you seek will only found in a litre.. yes? - this is where the problem lies engine weight and frame reinforcement.

    Carbon Fibre Frame springs to mind?
  8. More seriously... Hmm. Street Triple R? I'm not sure what they weigh in at, though. I thought it was down around 150 dry, from memory.

    I think I'd be looking at the hotly-tuned 600-ish motors (Daytona675, ST675, 600RRrRRrRR) in naked bikes, but even then it's a stretch. :-k

    If all those hard-as-nails Italian nakeds like the Brutale weren't 1000cc or more, I'd say they'd get close. Methinks the Street Triple R's about as close as it gets.

    Or Superduke mebbe.

    Edit: I think the hard part is that a 600cc engine+gbox weighs 60-70kg on its own... Can't do much about the 20L of fuel (another 15kg), or coolant and radiator (6-10kg?), or oil (3kg), so that's already 100kg before you get to the chassis, suspension and wheels...

    Some Formula SAE teams do interesting things with engines and turbochargers. There was a 120kg car with an 80 horsepower, 400cc thumper w/ turbocharger...
  9. How much power can be had from a NC35? Is there a more modern equiv?
  10. My baby is factory stated: 88.1Kw/118HP/120PS (no idea what at rear) at 155kg dry

    You need another toy, Stew?
  11. Looking at the Tech Specs of the Desmosedici RR , I think you may be right. Even one of those, you'd need to win Tattslotto and find someone willing to sell their pride and joy.

    Perhaps an old MotoGP 500cc two stroke? Wouldn't be road legal though.
  12. Found it... sought of...

    Carbon Frame + More

    ... only one catch its still a concept.

    Aprilia FV2

  13. Well, any 600cc I-4, 675cc I-3, or 750cc twin will make that sort of power reliably with a full exhaust system.

    Can get the 600cc I4's up to 140rwhp if you really want, but of course engine tractability and lifespan goes down. At 110rwhp it only takes a moderate state of tune for a super-sport engine to achieve that.

    My current super-sport makes more power than what I'm asking for in the OP at the rear wheel and it's had absolutely zero engine work done.
  14. Worked for Britten. In fact I think that bike would have come pretty close to meeting all your criteria, just a shame they're so rare and expensive.
  15. Thanks guys. Yeah, the only things that seem to fit are the truly custom bikes.

    I do think that the Street Triple 675 R may be the best starting point, especially if it's got the Daytona engine in it. Might still fall short of the target weight by 10kgs or so. All depends on what weight it's starting at.
  16. Do you have 10kgs you could lose? This is a cheap method, me I could lose 20kgs! :LOL:
  17. I've got 15kgs that I could lose. Am working on it (started going to the gym now as I plateaued with just trying to walk it off). All that added weight should be gone by the time I'm ready to buy the second bike.
  18. Hey Hey. Someone planning a new project heh?

    As for the wieght issue, I don't think you will get near it from any production based bike. Especially fully fuelled as you state. I reckon you could get some bike downs near 175 kg fully fueled but that would be about it. All manufactuers lie like sailors when it comes to claimed power and wieghts.

    But as for my suggestion.

    As cafe racer version of a KTM Superduke. Dump the motorcross bars. Add clip ons and a sporty exhaust and if money is no option, some carbon fibres wheels (These are an actual factory option). They will throw out around 110 hp as well with a massive midrange. Also lots of carbon fibre/titianium options to lower the wieght as well, but you still won't get to 150 kg's.

    Be interested to see how you go. Good luck and good engineering :grin:
  19. To meet your weight requirements, how about the 2008 KTM SMC/SMR.

    It has a chrome-molybdenum tubular space frame with most other components made from aluminium.

    It's 135kg dry, add 15kg for fuel and oil and it hits 150kg spot on.

    It only has 63hp but it you're not after longevity in the engine you could try fitting a turbo. Certainly would be interesting.

    If you're on the shorter, lighter side this would be your bike.


    It would also be a bucket load of fun :D
  20. I was going to suggest the Duke, but yeah, the lighter SM models would be better. A sensible turbo installation wouldn't necessairly affect engine life, but how would one go on a single in performance terms?