nos

Discussion in 'Motorized Bicycle General Discussion' started by mike125, Dec 22, 2008.

  1. mike125

    mike125 New Member

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    Hi im michael im 16 years old and i just purchased an 80cc motor and am looking to put a nos system on it what will work out thanks

    also the clutch seems really hard to engage and disengage is this normal?
     
  2. Creative Engineering

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    It seems like I saw this somewhere on the net.

    I doubt these engines would live very long on Nitrous.

    Jim
     
  3. TexasDav

    TexasDav New Member

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    hen I bought this Ibike MB it had a bottle made by NOS that catches the or equalizes the pressure of the intake manifold, http://motorbicycling.com/f15/ibike-before-after-4410.html

    I don't know if it does any good or not, It was there and so I left it, look at pic above carb. Check you cable adjustment on clutch and oil cable. Be sure the cable path is as smooth as possible with no sharp turns.
     
  4. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    NOS is a waste of time and money....and your engine if you use it.
    NOS is for racing, these engines are not.

    If you do it anyway, let us know how long it lasted before you blew it up. Oh yes, you will.
     
  5. jasonh

    jasonh New Member

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    agreed with Joe.

    These engines are cheaply made and are not designed for that type of thing. You'll get more and constant performance by adding a tuned pipe or doing other mods.
     
  6. Creative Engineering

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    Man I wish I could find this site again!
    you guys would get a real laugh.

    They're over in Ft.Frauderdale...they offer a mini Nitrous kit for the HT.

    It comes with a 60 second, 60 foot warranty. NOT!!! laff

    Depending on how you set it up and how much you know about Nitrous you can figure about 2 hours of fun...Being that the rest of the bike won't handle 10 HP why bother?

    Jim
     
  7. slipdrive44

    slipdrive44 New Member

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    Hey,

    I am 20 years old, a mechanical engineering student at University of Arizona and I work at Spookytooth Tucson, some of the guys on here use these bikes for main transportation, not as toys like us, so they are a little conservative.

    If you really just want a nitrous system that works, and is cheap, this is what you need.

    Go to a bike shop and get a CO2 tire inflator that takes the little non-threaded cartridges, then go to a smoke shop (some place they sell pipes and stuff) get some 8 gram Nitrous cartridges, 24 pack of ISI cream chargers, Whip-its, something of that nature.

    Now the inflator you bought is a little too tall for the nitrous canisters which are shorter than the CO2 canisters, what you do is stack about 5 pennies (yes real pennies like the money, change) So that the needle in the discharger will 'crack' the cartridge.

    You now have a nitrous discharger with that handle and its trigger. What I did was use a shcrader valve from an old bike tire, and epoxyd that into a length of fuel line (for one of these engines). The little bit of rubber on the valve from the bike tire helps it hold well stay under pressure so don't worry about getting it scraped off.

    Then just run the nitrous line back to your carburetor, position it so that it blows into the airbox. If you have one of the black 4 pipe down filter covers, push the tube into one of the downpipes, if you have one of the slatted round covers just ziptie the pipe into position blowing into the carb.

    I use the trigger on the actuator to hang the little discharger from a brakeline while getting up to speed, once you are cruising, just pull the trigger and you will feel a surge of power.

    IMO the boost is very controllable and my engine has gone through 20 charges with no problems, ZERO, if it is not actually better for the experience, I feel like it runs a bit more freely after feeling the power.

    The sad truth about nitrous is, you do only get a burst of power, and in the end you can't use nitrous to cruise so the point of it is a little lost in the fact that these bikes aren't quarter mile machines.

    TOTAL COST $40
    Inflator-$20
    24 pack of chargers- $12
    Fuel line-$5
    Valve, zipties, and glue-$3
     
  8. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    That sounds like the best way to do it if you are going to do it.

    I don't want to be a wet blanket, and my first post probably sounded that way.

    If you want to use NOS, or make ANY kind of performance mod, just be aware that you MAY shorten your engines life....is that relavent? Maybe not.

    I do remember finding out once, when building a "performance V-Twin" that there is a direct link between the lifespan of an engine and the amount of excitement it generates.
     
  9. slipdrive44

    slipdrive44 New Member

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    That is the nitrous kit that I use, and yes it is fun to be running WOT downhill and hit the trigger and feel the pull like you see in the movies, but the speedometer on my bike tells the true tail that Nitrous adds about 4mph.
    I can add 7-8mph just by pedaling hard. My bike is geared high enough I can pedal at top gear along with WOT.
    case in point: the added power from a surge of nitrous is less that what you can provide manually by pedaling. Not to mention the power from pedaling is available for longer and more convenient, plus it is safer.

    Either way, the way to go faster, really, and this is pretty much the absolute list:
    For the MOST out of your ENGINE safely and easily:
    1. Port match and polish intake and exhaust
    2. Upgraded Carburetor
    3. Expansion Chamber a.k.a. Tuned Pipe
    4. Best electrical components you can find (high performance plugwire and plug)
    5. Boost Port the cylinder
    6. Use Bel-Ray Si-7, or AMSOIL Saber (dirtbike racing 2-stroke synthetic oil) in LOW OCTANE fuel (it detonates more violently at the expense of smoothness)

    For the Hardware: The idea is to have the bike set up so that you can achieve a desired speed without trying to force the engine to rev beyond what it is made for.
    1. Use a 29inch wheel Cyclocross bike- as lightweight and sturdy as possible, made for racing
    2. Use either a highspeed low tooth rear sprocket as low as 25-27 teeth OR a shifter kit from SBP OR a modified scooter CVT bolted to the frame (this one is hard to do but it is AMAZING)
    3. Keep your tires at maximum running psi

    For the rider:
    1. weigh as little as possible.
    2. ride in bicycle racing attire, to minimize wind resistance ( this includes a helmet for safety)

    There you go. This is how to have a top speed bike, a lot of it also comes from luck of the draw on how your engine performs out of the box due to low manufacturing tolerances, few are F1 grade by sheer luck, most are just useable, some fight you every step of the way just to run.

    and it is absolutely true that the more you demand from your engine the lower its life expectancy will be. That is the point of doing everything possible to achieve high speeds with lower RPM through gearing. More speed= more vibration... vibrations make EVERYTHING fall apart, even you, so remember that just like in professional racing after every run with a "high performance" motor, you must go through and check and retighten EVERYTHING, because everything is subjected to so much more force than a daily easy rider.

    Have fun! and plan to work for every MPH you try to gain! You WILL burn through as much blood sweat and tears as you do fuel trying to get these to go faster, and lets not forget the investment side of the deal!

    $1000 High quality 29inch cyclocross bike
    $250 High quality SkyHawk engine from spookytooth
    $100 for upgraded carburetor
    $250 for Andyinchville's tuned pipe
    $200 for SBP shifter kit
    $100+ for labor on professional port and polish
    $50+ for Electrical and Fuel/Oil accessories
    $50+ for streamlined clothing and various expenses (parts etc.)

    TOTAL for "superbike" ~ $2000
    (...just buy a motorcycle on craigslist...)
     
  10. spad4me

    spad4me New Member

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    Slipdrive44

    I don't want to hijack This thread.
    Nitrous or nitromethane mean little to me .
    Slipdrive44 I did not know spookytooth was working on a cvt. Quote (a modified scooter CVT bolted to the frame (this one is hard to do but it is AMAZING) Unquote.

    A cvt on a bicycle engine is nice.
    Start a new thread.
    Post pictures.
    I will post mine.
    I have some nice cvt mods.
    both on a Happy time. and a 50 cc 4 stroke.
     
  11. ZnsaneRyder

    ZnsaneRyder New Member

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    Not everyone can pedal as fast as the motor takes them. 4 or 5mph is a good amount of extra speed for a bicycle. Besides top speed, I think the NOS would be good for added acceleration anyway.

    Say you are doing 20-25mph and need to cross an empty road to get into an upcoming turning lane, but cars are coming up from behind in the distance.... You want to cross the road as quickly as possible to not get hit by cars. This is one example of many that NOS would benefit a bicycle.
     
  12. slipdrive44

    slipdrive44 New Member

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    The biggest issue is that it isn't a constant and dependable source of power. Once you hit the canister it is done, and it costs about 50-60 cents per canister.

    I am working on a battery powered push button supercharger! This will be what you really need for that application!
     
  13. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    I have a little ducted fan motor that may just fill the bill for something like that- do a search (google or other) for GWS Electric ducted fan.
     
  14. slipdrive44

    slipdrive44 New Member

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    Just tried it.

    The problem I realized is that the motor forced induction for Super/turbo chargers is based on boost levels on the order of 10-30psi to pre-compress the cylinder air.

    There is no way I can see to achieve anywhere near these boost levels pre and post carburetor, The carburetor ITSELF will leak out the throttle cable port.

    Not to mention that the overall design of the twostroke engine is not designed to hold pressure like a four stroke with valves, our intakes and exhaust are simultaneously open, the only thing that this leads to is blow-through, no extra power, no pre-compression, just wasting fuel.

    The whole point of charging a fourstroke is to get precompression in the cylinder, unfortunately our motor designs, and all two-stroke designs, have the exhaust port exposed for many degrees of crank beyond the intake/transfers, so even if the cylinder had been pressurized from the intake all of it would blow out once the intake closed and the exhaust was still open.

    THIS is why the concept of expansion chambers is the number one way to improve performance of a two stroke engine, because the cylinder can ONLY recieve precompression from the LAST OPEN PORT, which is the EXHAUST.

    ...case in point... I need a tuned pipe, and forced induction will never work right like on a four-stroke, it may help get airflow at higher RPM, but it will never provide boosted power.
     
  15. Creative Engineering

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    slipdrive44,

    This asks the question...Why did Detroit Diesel put blowers on thier two cycle engines?

    I'll be back shortly and we can discuss NOS and supercharging.

    Jim
     
  16. slipdrive44

    slipdrive44 New Member

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    The Detroit Diesel turbo-compounding engines do not blow the intakes.

    They convert exhaust gas heat and pressure into further mechanical work through a series of "turbo-like" turbines.

    http://www.theicct.org/documents/Greszler_Volvo_Session3.pdf

    Not to mention the added weight and complexity of this as an exhaust based power system is not practical on a bike, especially a single cylinder which is much more affected by a tuned pipe.
     
  17. Creative Engineering

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    Go back a few years and look at the DDC 71 series engines...they were 2 cycle and supercharged.

    Jim
     
  18. slipdrive44

    slipdrive44 New Member

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    MY BAD! I saw you meant the intake blowers on the Detroit Diesels.

    [​IMG]

    How It Works The DD four exhaust valves and a blower, compared with a four cycle with only two valves and no blower. Each cylinder liner has a row of 14 oblong holes near the bottom. After the compression stroke, the piston travels downward, past this row of holes. This is similar to the way an outboard motor works. Except that once the piston goes below the holes, called scavenging ports, the blower forces air in at high pressure from what is called the air gallery cast into the block. Thus, the DD has not only water jackets, but air galleries cast in the block as well. This one thing that makes DD blocks more complex.

    The pressurized air then "scavenges" or forces out the burned gasses up through the four exhaust valves. This enables the engine to make only two revolutions to complete the combustion cycle rather that the four required of the four cycle engine, which relies on a second upward stroke of the piston to exhaust the cylinder of burned gas. In theory, this makes the engine more efficient. In reality, all the friction caused by all those extra moving parts eats up some of the efficiency gain. Why? Because of the drag created by the non-compression stroke, and the power to drive the blower and extra cam shaft. Even so, there is a major power gain through this design.

    The blower and turbocharger aspiration system constitutes another major difference. The four cycle engine is aspirated through intake valves next to the exhaust valves; the DD engine has only exhaust valves, but twice as many of them. The DD cylinder heads are very complex and expensive to replace if one gets damaged, such as cracking from overheating. All those extra working parts make for more potential trouble, but also increase efficiency considerably. This why, pound for pound, DD squeezes quite a bit more horsepower out of their engines than CAT does.

    Unfortunately, on the China made gasoline engines the design of the piston is meant to hold the fuel/air mixture and compress it in the crankcase to blow into the cylinder, on high quality 2-stroke engines of similar design a one way reed-valve placed between the intake manifold and the cylinder is the only way to maintain and keep a higher compression on the crankcase fuel/air, in which case a turbo might work, but only AFTER the carburetor as it would need to suck air through the carburetor to keep it moving otherwise the high pressure air system would blow the fuel back. This would necessitate a sealed and non-electrical post-fuel-addition boost system.

    It is possible. Here is my concept attached.
     

    Attached Files:

  19. slipdrive44

    slipdrive44 New Member

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    Also this would require something near a purpose built compressor to deliver needed power.

    like 24 CFM at 5 psi, something like that, to produce a 25% compression increase, supposing a reed valve already.

    IN ANY CASE: this will not add PRECOMPRESSION which is the fundamental purpose in most monds of a turbo or supercharger, and also the precompression is what adds the power.

    woohoo! power!
     
    #19 slipdrive44, Dec 24, 2008
    Last edited: Dec 24, 2008
  20. slipdrive44

    slipdrive44 New Member

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    as it turn out through some quick research, most air compressor that produce at least 20 CFM have 5 horsepower motors... haha...

    I suppose this makes sense seeing as our small 2.5hp engine at 80cc at WOT only does 17 CFM?
     

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