Advertise with Kiwi Biker
Page 2 of 2 FirstFirst 12
Results 16 to 25 of 25

Thread: 2 stroke emissions testing?

  1. #16
    Join Date
    13th July 2008 - 20:48
    Bike
    R1200RT LC
    Location
    Paremata
    Posts
    4,060
    Quote Originally Posted by george formby View Post
    Kinda wandering off topic but the new T7 Yamaha, CP2 parallel twin motor, has a 16ltr tank and is taking a big shot at the adventure bike market which demands big distances between fills. Yamaha claim 350kms to a tank, summit like 4.6ltrs / 100km. That strikes me as reasonably efficient considering it has the aerodynamics of a trampoline. I suspect it will only see the dealer for it's service.
    Bikes designed purely for commuting are far more frugal.

    One thing I've noticed wid 2t's, which abandons any emissions arguments, they love petrol! The more you stick in, the more they seem to like it. My DT230 is re-jetted (WR 200 jetting), goes like a cut cat and will slurp 11ltrs in less than 150km of grins.
    I've had 3 F800STs, BMW parallel twins. All were fuel misers, with good range from a 17 litre tank. About 4.6 l/100. It's been around long enough to be a good idea.

  2. #17
    Join Date
    24th November 2015 - 11:20
    Bike
    MV Rivale 800
    Location
    Blenheim and Welly
    Posts
    325
    It does make you wonder (And kind of getting back to the point in the OP) just what 2-strokes would be capable of consumption/emissions-wise if the manufacturers had been able to persist with them and thrown R+D time and money at them over the past 20+ years.

    Direct injection (Such as Piaggio's idea) would be great to see - I'd be fascinated to see just what the art of the possible is with such a set up.

    As for the F800 series Beemers - Great bikes that happened to be crackingly good on fuel too. From what I can see the only big (Over 500cc) mainstream bikes that focus on this aspect now are the NC 750 Hondas though I'm not sure what the latest F850 series Beemers are like.
    Navy Boy

  3. #18
    Join Date
    14th June 2007 - 22:39
    Bike
    Obsolete ones.
    Location
    Pigs back.
    Posts
    4,819
    Quote Originally Posted by Navy Boy View Post
    It does make you wonder (And kind of getting back to the point in the OP) just what 2-strokes would be capable of consumption/emissions-wise if the manufacturers had been able to persist with them and thrown R+D time and money at them over the past 20+ years.

    Direct injection (Such as Piaggio's idea) would be great to see - I'd be fascinated to see just what the art of the possible is with such a set up.
    Tell me about it!

    I suspect road going 2t's were canned, not due to emissions, but the realisation that advancing the technology would cut into profits. The CRM Active Radical, fuel injection, computer engine management, CAT's, performance and a dearth of moving parts would be less profitable than 4t's which require a higher capacity for the same bang and higher maintenance costs.

    I don't really smell a conspiracy but I do wonder what might have been. Quite often.
    Manopausal.

  4. #19
    Join Date
    25th March 2004 - 17:22
    Bike
    RZ496/Street Triple R/GasGas/ etc etc
    Location
    Wellington. . ok the hutt
    Posts
    17,117
    Don't write that off too quickly . On another thread apparently the Obama administration were responsible for marxists popes, so maybe they, or the shape shifting lizard people killed off the blue smokers.

    It's all making sense now


    Best I get up and go earn some more taxes.
    I've been told. Dreaming`s free.
    Think I'll go, back to sleep.
    Everybody listen, voices in my head
    Everybody listen, do yours say, what mine says?

  5. #20
    Join Date
    14th June 2007 - 22:39
    Bike
    Obsolete ones.
    Location
    Pigs back.
    Posts
    4,819
    Quote Originally Posted by F5 Dave View Post
    Don't write that off too quickly . On another thread apparently the Obama administration were responsible for marxists popes, so maybe they, or the shape shifting lizard people killed off the blue smokers.

    It's all making sense now


    Best I get up and go earn some more taxes.
    David Icke blamed the shape shifting lizard people for the demise of the 2t and chocolate bars getting smaller in one of his podcasts. He's an authority on these matters so you must be correct.

    It would be interesting to compare the emissions of carbie v FI 2t's. The KTM Enduro models come road legal in some countries and US states. Apparently.
    Manopausal.

  6. #21
    Join Date
    25th March 2004 - 17:22
    Bike
    RZ496/Street Triple R/GasGas/ etc etc
    Location
    Wellington. . ok the hutt
    Posts
    17,117
    Well I've just had a piss off the balcony and it was quite glorious. Got some fair distance which isn't always apparent standing at the bowl.



    Maybe this is more of an Instagram thing. Not sure how that works. Can I post a video?
    I've been told. Dreaming`s free.
    Think I'll go, back to sleep.
    Everybody listen, voices in my head
    Everybody listen, do yours say, what mine says?

  7. #22
    Join Date
    2nd November 2008 - 21:50
    Bike
    speed triple
    Location
    Hamilton
    Posts
    50
    Quote Originally Posted by AllanB View Post
    Old vehicles will get exemptions of some form - may be km limited or with the current government more likely you'll be taxed higher if you own a pre XX vehicle.
    I think so too . A 40 buck rego for an old clunker is to good to be true..

  8. #23
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,125
    Quote Originally Posted by rastuscat View Post
    Bikes appear to be smokier because you can see the smoke. Thing is, emissions aren't just the smoke you can see. For this reason, a 350cc bike emits less hydrocarbons than a 1600cc car despite appearing to be a lot worse.

    I'm not sure about this, but it kind of makes sense. Any of you scientist types care to advise?
    Well... it's not straightforward and it certainly isn't as simple as emissions are in proportion to engine size. There's emissions from unburnt fuel (vapour out of the tank or intakes), emissions from high combustion temperatures like nitrogen oxides, sulphur emissions from nasty fuel, and things like soot and particulates which is not good to breath in. Then there's the noise emissions, Harley rally anyone?

    The bit that's a surprise is that you can get small engines that are dirty and large engines which are relatively clean. Small displacement two-strokes are among the worst because there's a lot of mixing of exhaust and inlet charges. High performance 4 strokes which use valve overlap and exhaust resonance will have a similar issue, it won't be as bad per cc but since there are so many more of them... But yeah, nothing's more obvious than a worn out diesel.

  9. #24
    Join Date
    28th January 2015 - 16:17
    Bike
    2000 Ducati ST2
    Location
    Lower Hutt
    Posts
    1,125
    Just reading the posts above...

    Fuel consumption is helped by ratio of cylinder volume to surface area. A high volume to low area means low radiation heat loss to head and piston. There's also inertial loss, pistons and conrods being thrown back and forth does require energy. So does bearing and ring friction. The most fuel efficient engine is large displacement, limited number of cylinders, low revving, square or undersquare bores. This is exactly not what racing competition, where it's all about HP / cc, has given us... thirsty engines that rev like hell and are all about throwing air and fuel through as fast as possible.

    Two strokes: a really interesting type was opposed piston, uniflow, positively scavenged by blower. By the time you've done all that though you might as well make a 4 T. Would be really interesting to see what a modern, direct injection version of that could do.

  10. #25
    Join Date
    24th November 2015 - 11:20
    Bike
    MV Rivale 800
    Location
    Blenheim and Welly
    Posts
    325
    Quote Originally Posted by OddDuck View Post
    Just reading the posts above...

    Fuel consumption is helped by ratio of cylinder volume to surface area. A high volume to low area means low radiation heat loss to head and piston. There's also inertial loss, pistons and conrods being thrown back and forth does require energy. So does bearing and ring friction. The most fuel efficient engine is large displacement, limited number of cylinders, low revving, square or undersquare bores. This is exactly not what racing competition, where it's all about HP / cc, has given us... thirsty engines that rev like hell and are all about throwing air and fuel through as fast as possible.

    Two strokes: a really interesting type was opposed piston, uniflow, positively scavenged by blower. By the time you've done all that though you might as well make a 4 T. Would be really interesting to see what a modern, direct injection version of that could do.
    In a way that explains why my H-D 48 does quite well on fuel, as does my wife's Sportster 883. The bore and stroke of the motor as well as it being low revving are all in its favour with regards to this particular argument. I guess that's partly the reason why the Honda 750NC motor does so well too.
    Navy Boy

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •