my stock bike toped out 51km\h!!!

Discussion in '2-Stroke Engines' started by wackey101, Jan 16, 2011.

  1. wackey101

    wackey101 Member

    my bike just got 51 km\h on flat surface what im running:
    25:1 ratio fuel and oil
    ngk bp6hs spark plug
    44 tooth sprocket
    F80B 66cc/80cc
    everything is stock wow cant wait for upgrades
    Last edited: Jan 16, 2011

  2. motorpsycho

    motorpsycho Active Member

    That's 31 mph.
    are you running 26 inch wheels?
    my bike with an 80 c.c. 2 stroke, 20 inch wheels, 24 inch tall rear tire and a 41 tooth sprocket will top out at 32 mph on flat ground. the only mod that has been done to it???
    a modified stock muffler on a long exhaust pipe, a velocity stack with a high flow filter, an ngk spark plug and an 8 mm. Accell spark plug wire.
    I'm running 32:1 oil-fuel ratio.
    my other bike with a 50 c.c. 2 stroke, 20" wheels, 21 inch tall rear tire and a 41 tooth sprocket will just get to 30 mph. the mods done to it are a spooky tooth expansion chamber (which is tuned for low end torque), modified stock muffler, ngk plug, 8mm Accell spark plug wire and a high flow k&n air filter.
    also running it at 32:1.
    I weigh 150 lbs, which definitly helps.

    26 inch wheels will give you more top end than 20 inch wheels (like i have).
    but, 31 mph totally stock is a good start.
    Last edited: Jan 16, 2011
  3. wackey101

    wackey101 Member


    dude thnx for your reply yes its 26" any body elese want to list there top speed with there specs
  4. HeadSmess

    HeadSmess Well-Known Member

    78.9km/h downhill with guesstimated oilratio, stock plug and a silly li 36 tooth cus i was one link short with my new chain to stay stock... 26 "rims... what else?

  5. geebt48cc

    geebt48cc Member

    Hey there guys,

    I just got a slant 66cc, and looking forward to seeing on 28" wheels. Ok, just got to tell you guys that my 48cc skyhawk mtb on 26", 32:1,NGK,wire,Free flow filter,SBP expansion,port matched on 44T---can hit 34.8 on flat. (But, I go easy 90% of time) PS-I weigh 255...
  6. blue 48

    blue 48 Member

    76kmh 50:1 rear tooth unsure, 26" wheels rock solid 48 or 49cc dunno bout that yet only had it 2 weeks and cops pulled me over and told me hed clocked me at 76 on flat gnd i use 100 octane fuel and penrite oil i got it second hand and have not been told much about it. but it aint normal thats for sure all i know its done about 400 kms since new
  7. motorpsycho

    motorpsycho Active Member

    ummm, that would be 47.22 mph.
    sorry, but i'm not buying it especially because 100 octane fule is useless in one of these engines, unless you have an high compression head and/or domed piston. (which would make it very hard to start). most kits come with 44 / 41 tooth rear sprockets and to get max speed you need to drop to a much smaller rear sprocket. By dropping to a smaller rear sprocket you will lose a ton of take off power. you'd have to pedal the bike up to 15-20 mph before the motor would even start to pull it on it's own. so unless your bike is set up with a 36 or smaller tooth rear sprocket, or a shift kit i doubt that your bike would get up to 47 mph.
    add in rider weight, wind resistance, tires, and all that speed robbing stuff, and i am very doubtful that it was 47 mph.
    now, if this motor is not 100% stock and has a ton of mods done to it with a light weight rider on a non windy day...maybe 47 mph.
  8. My bike has alot of mods, and a 36 tooth sprocket (well I'm putting on my shiftkit now). Anyway I can only get to just over 42MPH on the flat. That's mixed at 20/1.

    BTW I only weight 135 lbs.
  9. nathonix

    nathonix New Member

    oil mix 25:1(duplex brand oil, regular unleaded) stock 44 tooth, stock carb, so on so forth stock 48cc engine with a carb that was improperly installed at an angle so as to facilitate the small frame would run 28 on a flat with 26 inch rims, and i weigh 240lbs. downhill has hit 37.8mph

    have new lighter frame, and a short fit expansion chamber, but have yet to give it a speed test, mostly out of having to work and not having everything entirely rigged up properly.
  10. adrian101

    adrian101 Member

    Awesome work, Mines an f80b also. stock, but I'm just breaking it in. Nice speed thou for a stocky
  11. damo99

    damo99 New Member

    i'd like to know how most people measure there speed.i think you'll find that if you used a gps your speeds will be alot lower.
    i have 4 motored bikes the only one that gets over 40klms is my new cruiser with a gt-5 high comp head, nkg -bp6hs plug, sbp expansion chamber , boost bottle(all it does is help idle),speed carby and sbp shift kit (34-14)7 speed. on flat ground in 6th (16tooth)gear top speed 63klms.
    my friend who has a 66 (z box)keeps telling me he gets 55klms on a 44 tooth rear sproket . so i got my gps took it for a ride -top speed 35klms (just).
    i used to think i was going a lot faster with one of the bike computors set up by the instructions and it said i was doing over 50klms when i wasn't .
    theres to many vairiables setting up the bike computor ,you might have 26 inch wheels and insructions say set at a scale of 200 but it all depends where on the spokes you put the magnet . 1 cm up or down can be a big diffrence to your speed. also it also depends on the distance between the magnet and pickup .if your wheel has a very slight buckle this will affect the pickup giving a wrong reading
    this is just food for thought
  12. shell shock

    shell shock Member

    whoa... not to be a bummer, but my stock bike tops out at 50 km/h. i might want to re-check things on your bike
  13. damo99

    damo99 New Member

    not a bummer but how did you measure your speed
    as i said before the only realy accurate way is by gps
    even a car sitting next to you isn't accurate
  14. shell shock

    shell shock Member

    twas on a gps. mind you that was last season. shes been beat since then, as well as put on a heavier bike. she now tops around 45km/h. ****... lol hows progress on your end?
  15. adrian101

    adrian101 Member

    okay update

    53km on the straight flat

    26" coaster bike
    F80b engine
    Speed caby
    Stock plug
    Stock muffler
    32:1 oil to fuel mix
    44t sprocket
    and i weight 112kgs lol

    What i have coming in the mail: expansion chamber, after market bullet head, NGK wires and plugs, a new and not bent 36t sprocket, "nos kit" which i will not use but it's for show ;)
  16. shell shock

    shell shock Member

    you might want to re-think the coaster brake... sides that, nice and simple. man you have to update us when you get all your accessories in!
  17. adrian101

    adrian101 Member

    For the coaster brakes, i took it off and the back rim, i got a simple 26" mountain bike back rim, I took the mountain bike cogs/cassettes off the back rim and replaced them with a freewheel one piece cog.

    I put V brakes on the bike to replace the coaster.

    Reason for taking the coaster brakes off, I have a bad habit of peddling backwards when on motorized bikes. Them brakes prevented me from that habit so i had to in stall a freewheel fixie lol
    Last edited: May 9, 2011
  18. shell shock

    shell shock Member

    there we go, thats the way to do it!

    (ps, 100th post... WOOO!!! this is cause for celebration *raises a glass of locktite*... er maybe not.. XP)
    Last edited: May 9, 2011