1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Discussion By god they can go ....

Discussion in 'The Pub' started by trevorlatala, Oct 12, 2020.

  1. trevorlatala

    trevorlatala Active Member Premium Member Contributing Member

    Messages:
    49
    Likes Received:
    41
    Trophy Points:
    188
    Joined:
    May 27, 2018
    Gender:
    Male
    Occupation:
    electrical engineer
    Location:
    Staffordshire United Kingdom
    My Bike:
    Hondavt700 Honda CB250 rs Hyosung SV250 Jawa ts 350 ETZ 250
    I was out today with my wife Ann in her BMW Z3 sports car driving through the peak district in Staffordshire - Derbyshire This is a very hilly area When we were overtaken by a learner on his whatever 125 motorcycle ! Well bugger me these can really go up hill he was doing 50 plus and down hill 60 plus
    What are these new bikes doing my 250 ,s and 350 can only keep up at these speeds Come on guys what am i missing out on
    Trev
     
  2. jmw76

    jmw76 Well-Known Member Premium Member

    Messages:
    492
    Likes Received:
    231
    Trophy Points:
    248
    Joined:
    Mar 12, 2017
    Gender:
    Male
    Location:
    Melbourne, Australia
    My Bike:
    Honda cbr250rr mc22 road + 1 track, Honda RC 162 tribute bike, Honda Spada Vt250, Honda CBR900RR
    Not sure what bikes you have. An old Honda cbr250rr or any of the 250 4 cylinder sports bikes of that period are quite spritely and enjoyable to ride. If you are just interested in outright performance from a 250 then the 2 stroke pocket rockets are the thing, but they require a bit more maintenance.
     
    • Agree Agree x 2
  3. trevorlatala

    trevorlatala Active Member Premium Member Contributing Member

    Messages:
    49
    Likes Received:
    41
    Trophy Points:
    188
    Joined:
    May 27, 2018
    Gender:
    Male
    Occupation:
    electrical engineer
    Location:
    Staffordshire United Kingdom
    My Bike:
    Hondavt700 Honda CB250 rs Hyosung SV250 Jawa ts 350 ETZ 250
    My bikes are listed as I can see so are yours
    This little thing was nothing more than a 125 single but by gum he was giving it some stick !
    I really enjoyed watching him go I could tell he was a learner though as he seemed to be ballet dancing on the brake pedal That is according to his brake light
    I really admire any one who gives it his all possibly getting a 100 miles to the gallon as well
    Trev
     
    • Like Like x 2
  4. DannoXYZ

    DannoXYZ Active Member

    Messages:
    95
    Likes Received:
    37
    Trophy Points:
    188
    Joined:
    Sep 7, 2017
    Occupation:
    IT Manager
    Location:
    S.F. Bay Area
    My Bike:
    Honda CB125TT, Kawi EX250, Ninja 250R street, Ninja 250R race, Honda CBR250RR-MC19, CBR250RR-MC22, VF500F, CBR600RR
    My wife's CB125T has 17bhp and gets 100mpg! Tops out just over 110kph! :)
    Such a fun bike to ride!
     
    • Like Like x 1
  5. trevorlatala

    trevorlatala Active Member Premium Member Contributing Member

    Messages:
    49
    Likes Received:
    41
    Trophy Points:
    188
    Joined:
    May 27, 2018
    Gender:
    Male
    Occupation:
    electrical engineer
    Location:
    Staffordshire United Kingdom
    My Bike:
    Hondavt700 Honda CB250 rs Hyosung SV250 Jawa ts 350 ETZ 250
    I have always loved the concept of getting a lot out of a little I have even fantasised of getting 100 mph out of a 50 cc machine
    Fuel injection turbo and a slippy shape
    I cannot say how much I enjoyed watching the guy getting the max out of the minimum
    Trev
     
  6. Murdo

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

    Messages:
    5,669
    Likes Received:
    4,289
    Trophy Points:
    1,148
    Joined:
    May 4, 2013
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Tamworth, NSW
    My Bike:
    1938 Royal Enfield 250, CF 250 V5 and 650TK, XL250, CBR250, plus a few others.
  7. jmw76

    jmw76 Well-Known Member Premium Member

    Messages:
    492
    Likes Received:
    231
    Trophy Points:
    248
    Joined:
    Mar 12, 2017
    Gender:
    Male
    Location:
    Melbourne, Australia
    My Bike:
    Honda cbr250rr mc22 road + 1 track, Honda RC 162 tribute bike, Honda Spada Vt250, Honda CBR900RR
    Yes. There is real satisfaction out of getting the most out of little bikes. Anyone can go hard on a 1000.
     
    • Agree Agree x 2
    • Well said! Well said! x 1
  8. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    4,124
    Likes Received:
    2,734
    Trophy Points:
    923
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    Just buy an NSR 150 if you want to play dragonslayer.
    Honda_NSR_150_L_1.jpg
    In fact, this would be the perfect track day bike, 40hp. Everyone passes you on the straight and you pass them all again before you finish the lap.
     
    • Like Like x 2
    • Agree Agree x 2
    Last edited: Oct 13, 2020
  9. trevorlatala

    trevorlatala Active Member Premium Member Contributing Member

    Messages:
    49
    Likes Received:
    41
    Trophy Points:
    188
    Joined:
    May 27, 2018
    Gender:
    Male
    Occupation:
    electrical engineer
    Location:
    Staffordshire United Kingdom
    My Bike:
    Hondavt700 Honda CB250 rs Hyosung SV250 Jawa ts 350 ETZ 250
    there must be some kind of formula for the speed of yer bike against ist horsepower rating
    taking things like drag etc into account
    any one have any tables
    Trev
     
    • Like Like x 1
  10. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    2,306
    Likes Received:
    999
    Trophy Points:
    693
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    Only thing which comes close to a formula I can think of is when Barry Sheene was commentating the 500 GP races.
    He'd always be lauding the speed and power of the Hondas and say that at those speeds each extra horsepower was one extra kilometre per hour by the end of the main straight
     
  11. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

    Messages:
    4,124
    Likes Received:
    2,734
    Trophy Points:
    923
    Joined:
    Dec 23, 2012
    Gender:
    Male
    Location:
    Thailand
    Home Page:
    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    Err nope. Wind resistance is the killer. As with everything it will square with the speed so it only takes 40 or a little less to do 100mph and about 200 to do 200mph. After that it gets really crazy. The Ducatis have gobs more power than the Yamahas even though they might only be 12kph faster.

    You would think a simple comparison would be easily found on the internet of things but not so. Here are some links if you want to mess about
    https://www.omnicalculator.com/phys.../www.omnicalculator.com/physics/drag-equation
    http://elmoto.net/showthread.php?t=3400
     
    • Like Like x 2
    Last edited: Oct 14, 2020
  12. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    2,306
    Likes Received:
    999
    Trophy Points:
    693
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    You're disagreeing with Barry Sheene...always loved his comment - "like a rat up a drain pipe"
     
  13. DannoXYZ

    DannoXYZ Active Member

    Messages:
    95
    Likes Received:
    37
    Trophy Points:
    188
    Joined:
    Sep 7, 2017
    Occupation:
    IT Manager
    Location:
    S.F. Bay Area
    My Bike:
    Honda CB125TT, Kawi EX250, Ninja 250R street, Ninja 250R race, Honda CBR250RR-MC19, CBR250RR-MC22, VF500F, CBR600RR
    While wind-resistance (aero-drag) goes up to square of speed, power-required to overcome that resistance goes up by cube-function of speed. So it requires eight times power to just double speed.

    For example, it requires about 9bhp go push bike through air at 100kph.
    To make it go 200kph, requires about 70-75bhp.
     
  14. DannoXYZ

    DannoXYZ Active Member

    Messages:
    95
    Likes Received:
    37
    Trophy Points:
    188
    Joined:
    Sep 7, 2017
    Occupation:
    IT Manager
    Location:
    S.F. Bay Area
    My Bike:
    Honda CB125TT, Kawi EX250, Ninja 250R street, Ninja 250R race, Honda CBR250RR-MC19, CBR250RR-MC22, VF500F, CBR600RR
    He's not necessarily disagreeing with Barry, who's not talking about ultimate top-speed given unlimited runway, but acceleration to end of straight. So effects of extra power given extra speed at end of straight isn't as great as would be realised with more road.
     
  15. DannoXYZ

    DannoXYZ Active Member

    Messages:
    95
    Likes Received:
    37
    Trophy Points:
    188
    Joined:
    Sep 7, 2017
    Occupation:
    IT Manager
    Location:
    S.F. Bay Area
    My Bike:
    Honda CB125TT, Kawi EX250, Ninja 250R street, Ninja 250R race, Honda CBR250RR-MC19, CBR250RR-MC22, VF500F, CBR600RR
    Hey, thanks!!! That list of bike cross-sections are very handy! Can plug into this equation to determine how much power is needed to reach any particular speed on any particular bike:

    TotalPower = aWS + (rho/2)CdCaS^3 where

    a = coefficient of rolling-resistance of tyres, and drivetrain (bearings & gears)
    W = weight of bike+rider in Newtons
    S = speed in meters/second

    rho = air-density (temperature and elevation dependent, so you'll have to expand on this)
    Cd = coefficient of drag, depends upon smoothness of body-shapes
    Ca = frontal-area of bike+rider in square meters, mirrors add surprising amount of area

    Notice that the 1st term (rolling-resistance) goes up linearly with speed while the 2nd term, power required to overcome wind-drag goes up to the cube-power of speed. When you go from 100 to 300kph, rolling resistance goes up 3x while power-required to overcome wind-resistance goes up by 3*3*3=27x !!! This is why you want to focus on aero-mods to improve top-speed. Easier than increasing gobs of power!
     
    • Agree Agree x 2
    • Like Like x 1
  16. mboddy

    mboddy Well-Known Member Premium Member Contributing Member

    Messages:
    366
    Likes Received:
    303
    Trophy Points:
    298
    Joined:
    Mar 18, 2012
    Gender:
    Male
    Location:
    Canberra
    My Bike:
    Yamaha 250cc 2 stroke
    On a push bike you provide all the power. Recumbents are faster because they have less frontal area.
    Around my local area I can pedal my recumbent trike up to 60kph.
    Once I fitted a small nose cone that increased to 80kph.

    I took a Trisled racing trike for a ride around the bike race track.
    It is fully enclosed with only a few cm of the bottom of the tyres exposed.
    The track has quite an uphill slope around the back of the circuit.
    When I got into it my heart sank when I saw that the only front sprocket had 80 teeth.
    I thought there was no way I would be able to get it up the hill.
    But when I tried it we just sailed up it really fast.
    The hill was nothing compared to wind resistance.
     
    • Like Like x 2
  17. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    2,306
    Likes Received:
    999
    Trophy Points:
    693
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    I can think of one way to get more power on a bike, but I am uncertain as to the conversion between horsepower and sheeppower or if it's going to go any faster with that wind resistance

    Wallace-Gromit-sheep-bike.jpg
     
    • Funny Funny x 3
    • Like Like x 1
  18. DannoXYZ

    DannoXYZ Active Member

    Messages:
    95
    Likes Received:
    37
    Trophy Points:
    188
    Joined:
    Sep 7, 2017
    Occupation:
    IT Manager
    Location:
    S.F. Bay Area
    My Bike:
    Honda CB125TT, Kawi EX250, Ninja 250R street, Ninja 250R race, Honda CBR250RR-MC19, CBR250RR-MC22, VF500F, CBR600RR
    Now.... if all those sheep were to fart at same time....
    ... and we ignited it.... hmmmm....
     
    • Agree Agree x 1
    • Funny Funny x 1
  19. Andych

    Andych Senior Member Premium Member

    Messages:
    3,241
    Likes Received:
    1,746
    Trophy Points:
    898
    Joined:
    Oct 6, 2016
    Gender:
    Male
    Location:
    Sydney
    My Bike:
    1987 Yamaha SRX250, Honda 1975 CB400F, Honda 1991 250 Spada, Honda CT110 1986 Postie Bike
    That would probably have a level of difficulty on a par with tuning FZR250 carbies first go.. :)
     
    • Funny Funny x 3
    • Like Like x 1
  20. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

    Messages:
    2,306
    Likes Received:
    999
    Trophy Points:
    693
    Joined:
    Oct 1, 2013
    Gender:
    Male
    Location:
    Narrabeen, NSW Australia
    My Bike:
    Yamaha FZR250 3LN1
    I think that has likely never happened, ever!

    They are worse than trying to play a game of Jenga whilst juggling three pins whilst balancing a plate on a stick on your nose with a hula hoop going on one leg whilst hopping over a skipping rope
     
    • Like Like x 1
    • Funny Funny x 1

Share This Page