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Thread: Racing exhaust for laker 49 OMC

  1. #101
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    Default Your time frame is a little off

    Quote Originally Posted by Powerabout View Post
    the 2 stokes left the Gp bikes at the end of last year due to some lobbying by Honda

    The 2-strokes actually left the top class of F-1 bikes several years ago (2002), and I would not doubt that Honda had something to do with it, but I think if you research it, cubic dollars had a lot to do with it, as it was costing the manufacturers that were left at the time, which were only a couple besides Honda, millions of dollars each year to compete with bikes that the technology to develop them had nothing to do anymore with what they were manufacturing for the worldwide motorcycle market due to emission requirements worldwide, i.e. 2-stoke versus 4-stoke.

    They (sanctioning body/promoter of the series) made the decision to go to a 4-stroke engine, of 1000CC's at first, ran those for several years, then went down to 800CC's for a while, got those motors turning faster lap times than the 1000CC models with development, and now are going back to 1000CC limits as no manufacturer makes an 800CC engine for wide use on the road. It all comes back to being able to write of development costs for the road bikes and let the technology trickle down to them.

    This brought Kawasaki, Suzuki, Ducati, and several others back to GP racing as the 2-strokes they were trying to compete with against others, were no longer competitive ( some never were, and some simply chose not to compete in the top class as they did not have product and the cost was prohibitive to develop it) against Honda and Yamaha with the two strokes they were building at the time as they had gone to 4-strokes on the road bikes, were not building 2-stokes anymore (at least in the large road bikes), and they were not willing to continue to spend the large amounts in development costs to compete when there was no payoff for the bikes they were making for sale to the public. I just saw a former GP rider who is now a promoter on a motorsports show last Sunday night talking about just the transmissions that are used at present in the GP bikes costing a MILLION DOLLARS per each.

    I would not argue that Honda probably had some input into the formula, but the overiding reason for the demise of the two stoke was emissions and money being spent there was no longer any write off for or benefit in the development on the road bikes, as the road bikes had gone to 4 stokes for that reason (emissions). Plus of course that "Harley " sound versus the Japanese 2-stoke sound of "ring-a-ding-ding".

    Would really be interesting to see just what could be done with a two stoke emissions/max power wise if carried to the state of the art as possible today with computerized fuel and spark delivery. It looks as though the outboard manufacturers have just stopped or cut way back on development of 2-stokes in todays economic situation, by going the path of least resistance of 4-stokes, with the exception of the Optimax from Mercury and the 2-stroke product from Bombardier. Even the small engine folks such as the manufacturers of lawn and garden, ATV, Jet Ski and others have felt the heat and given in to the 4-stroke trend. Of course they as mass market manufacturers also have BOD's to answer to and the profit motive to make, unlike the small specialized high performance builder such as GRM and VRP. That is unless the emissions police get really tough and don't want anybody to have any fun anymore.

    I have changed the link shown previously in the earlier post referencing the NS500 to a better way to reverence the Honda GP bikes, both 2 and 4 stroke with more info.

    ADD: My apologies to Tim Kurcz for hijacking his thread with the last few posts, but since I have always been interested in engine technology, especially two stoke type, when the "oval piston" comment was made I thought it would be interesting to some who may not have been familiar with the engine to give some reference to it.

  2. #102
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    What I meant was they left the smaller GP classes last year so no more GP's with 2 stokes
    Clearly they left the 500 class a few years back.
    Has any 4 stroke got the the power levels of a 2 stroke yet per cc?
    Thanks for the interesting info Bill

  3. #103
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    I heard not too long ago, I believe during the Daytona bike telecast that the Moto GP bikes put out about 200-220 HP out of 800CC. These of course are 4-stroke. I did not hear RPM given but I understand that F-1 car makers including Ferrari had much input on the valve train design of the engines used. The car engines have used pneumatic valve opening and closing for quite some time now and I remember hearing they rev as high as 18,000RPM. I seem to remember hearing that type valve train may have been outlawed recently to help contain cost although I am not positive about that.

    The VRP and Rossi 500CC 2-stokes are claiming around 240HP and I have not heard the RPM they develop that at or whether it is dyno proved, although the 125CC single cylinder engines by the same manufacturers were turning 13,500 and supposedly pulling as much as 50HP as long as 8-9 years ago. The 500's of course are 4 cylinders, and each of the larger engine models are simply multiple cylinder models starting at 125CC then 250CC, and going thru 500CC, although the 350CC current models are twin cylinder of the same design as the 250's. (2 cylinder) All have had much more development since then, so I would not doubt that kind of HP with the 500. It may be more than just 1/2 as much HP in the 250CC model as you have less friction loss with only two cylinders instead of four, but the same cylinders, carb size, and expansion chambers. The two cylinder 350CC engines are definitely more "torquey" and have more punch out of a corner than a 4 cylinder of the same displacement or that is what seems to be proven on the race course these days.

  4. #104
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    no demise of 2 stokes check this
    http://www.suterracing.com/en/suter500.html

    (I think we need a new thread on modern 2 strokes)

  5. #105
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    Default Good news & bad

    Good news: On the subject of engine technology - I'm all about it! A thread dedicated to advances in 2 & 4 stroke technology would be great!

    Bad news: Regarding the modified Nydahl "laker" exhaust, no deposits were received, so I'm scrapping the project except for my own engines. If I get bored next winter, a few may be built and offered.

    For now, it's back to the shop where six customer towers, six exhaust systems, a NBRA 49.9 and 49.9 OMC turbo are in construction.

    Enjoy your 2012 season!

    Tim

  6. #106
    Mike Beegle tunnelboat's Avatar
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    Tim try posting on Screamandfly.com More of a lake racer group..

  7. #107
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    Default Faster

    Quote Originally Posted by tunnelboat View Post
    Tim try posting on Screamandfly.com More of a lake racer group..
    Thanks Mike,

    Will do sometime next winter. Too busy right now anyway. Have a great season!

    Tim

  8. #108
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    Quote Originally Posted by Tim Kurcz View Post
    Bad news: Regarding the modified Nydahl "laker" exhaust, no deposits were received, so I'm scrapping the project except for my own engines. If I get bored next winter, a few may be built and offered.

    Enjoy your 2012 season!

    Tim
    g,day mate,oh thats a shame r.e your exhaust project!!
    so with your exhaust project idea,would that allow a two stroke expansion pipe to be succesfully fitted and work and run nicely ??
    i really want to fit a jet ski pipe from www.factorypipe.com
    you can see my new thread on here r.e expansion pipes,http://www.boatracingfacts.com/forum...engine-possble
    can you please email me more info/price r.e your exhaust kit??
    my email is toprank_mt_racing@hotmail.com
    hope to hear from you soon tim
    thanks mate
    glen

  9. #109
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    I recall a photo of Honda's oval piston set up: There were two connecting rods side-by-side, and the length was about 1.5 times the width. This was for a 4 stroke engine, and it had (as I recall) 8 valves, hence the reason for the oval shape.

    Jeff

  10. #110
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    Quote Originally Posted by Fastjeff57 View Post
    I recall a photo of Honda's oval piston set up: There were two connecting rods side-by-side, and the length was about 1.5 times the width. This was for a 4 stroke engine, and it had (as I recall) 8 valves, hence the reason for the oval shape.

    Jeff
    Just Google NR 500 and you'll find photos.
    David



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