very new to this motorbike thing with a few questions

Discussion in 'Motorized Bicycle General Discussion' started by bro-die, Dec 22, 2011.

  1. Greg58

    Greg58 Well-Known Member

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    Yes, the nuts on both of my 48cc engines are a 10mm, the first is a grubee and the other is a BGF. I thought it would help identify his engine. If you look at his pics it looks like the head and intake and clutch lever nuts are the same, all on mine are 10mm.
     
    #21 Greg58, Dec 24, 2011
    Last edited: Dec 24, 2011
  2. Greg58

    Greg58 Well-Known Member

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    Bro-die, If your engine is new it will get better after your break-in miles. On my first build it was around 300 miles or so when the bike started climbing the hill that until then I had to pedal to keep the engine from dieing. So if it is running well as you say just keep on riding. MERRY CHRISTMAS
     
  3. bro-die

    bro-die New Member

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    ALLLLLRIGHT!! thats good to hear. merry christmas all. I just ordered a couple of parts from SBP and will ride tomorrow. All comments are welcomed as I said i never even touched a 2 cycle engine in my life. Im so new I didnt even know there was a button to prime the gas till I saw it on youtube.
     
  4. rustycase

    rustycase Gutter Rider

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    Hey BD,
    I'm trying to figger what u mean, 'died out on the hill'.

    Mine barely makes it up some small rises, at little more than walking speed, but does plug right along. Sometimes I pedal a bit, but never very much.

    You'll need to make a choice between going for top speed, or conquering that hill you spoke of. :)

    The option here is to get a shifter kit.
    Most reports regarding them are good.

    The button to push on the carby... it's only for bleeding air out of the input line... that is, if you DO have an NT... NT uses a choke for cold start enrichening.

    Tell us more abt this hill, and more abt what 'die' means and details... :)

    ...I got hills around here I just don't even attempt to conquer! lol

    Best
    rc

    Merry Christmas to all !
     
  5. nightcruiser

    nightcruiser New Member

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    Don't get discouraged, I started out the summer at about 225LBS and my bike could pull me up a steep hill without pedaling. From a pedal start at the bottom of a hill the motor would get me up to about 20MPH going up the hill without pedaling. (this is a steep hill but not a suicide hill!) Average flat land high end speed is around 30MPH, but at times I had been getting more around 35MPH.
    Just break in your motor and get on a regular mix, then tune the carb a bit and you should have what you are after...
     
  6. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    With a shift kit, you will conquer most hills. This depends on your overall gear ratio.

    With a 36-tooth rear sprocket, your ratio is 14.76:1. Not too good for climbing hills.

    With SBP shift kit and the lowest gears possible, you might want to use all 8 speeds.

    The engine has 4.1 built-in gear reduction and 10t gear. Connected to a 17t jackshaft (4.1 x 1.7 = 6.97:1).

    The second jackshaft sprocket can be 9t or 10t. Connected to a 44t chainring sprocket, that gives you 37.173 or 33.456:1.

    Using a 30t chainring sprocket and a 32t first gear on your cassette gives you 39.65:1 or 35.69:1. That's equivalent to a 97-tooth rear sprocket or a 87-tooth rear sprocket.

    The lowest gear ratio I can calculate would be with (4.1 x 1.7) x (48/9) =
    37.173:1. Then using SBP's smallest 24t chainring and the largest (most) available 11t/34t rear cassette, you'd get

    37.173 x (34/24) = 52.66:1, which is equivalent to a 128t rear sprocket.

    The 8th gear in this combo is 17:1, equivalent to a highway 42t gear.

    With a 10t/48t chainring, it'd be 33.456 x (34/24) = 47.4:1, equivalent to a 116t rear sprocket.
    The 8th gear in this combo would be 15.33:1, equivalent to a 37t rear sprocket.

    A good all-around combination would be using a 30t bicycle chainring, that'd give you a 42.13:1, like a 103-toothed rear sprocket for first gear.
    The 8th gear in this combo would be 13.63:1, equivalent to a 33t rear sprocket.

    BTW, the first gear on my Tanaka engine/shift kit is 46.36:1, like a 113t rear sprocket.

    My 8th gear is 15:1, equivalent to a 37tooth rear sprocket. Since my Tanaka 47R engine can pull higher rpms than a Happy Time engine, 15:1 in 8th gear is not an issue. In fact, in cruising speed, I am in 7th gear @ 17.73:1, like a 43t rear sprocket.

    In first gear, my MB climbs hills like a dirt bike.

    Just food for thought at low end and high speed. xct2
     
    #26 5-7HEAVEN, Dec 24, 2011
    Last edited: Dec 24, 2011
  7. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    BTW, even with stiff gears, I still get 125mpg.dance1
     
  8. rustycase

    rustycase Gutter Rider

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    Whew!

    I'm gonna have to read THAT one over again.

    ...Lotta info there!
    :)
    rc
     
  9. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    I am long winded.laff
     
  10. bro-die

    bro-die New Member

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    Thats a whole lot of info right there thanks so much people. I will be switching bikes with multiple speed afterall because this single speed is just not cutting it. What I mean by "dying out on the hill" is that itll die out in th middle and since its a sigle speed its really hard to pedal so I walk the other half. Its a great bike and ill be doing mods after the first gallon and right now its takes alot to kill the gas on this thing. Im on about 1/4th way down to my first full tank and I still have the leftover from the first gallon. BTW i used super unleaded thats 97 octane I believe or I can be wrong but for sure I used super unleaded.
     
  11. nightcruiser

    nightcruiser New Member

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    I don't know, the 4 acorn nuts on top of that head look larger to me than what's on the intake/exhaust, hard to tell from a pic though.
    Maybe this is a good way to tell 48cc from 66cc, cause all the 66cc motors I have seen have had much larger studs and nuts on the head than the intake/exhaust (13mm or 14mm vs 10mm). I am still having a hard time believing the head studs and the intake/exhaust studs are the same size on even a 48cc, but you've got the wrench there and the motor to fit it on so I guess I have to trust you on that one. You can trust that what I am saying about the 2010/2011 Grubee 66cc is correct, the head studs and nuts are larger than the intake/exhaust...
     
  12. nightcruiser

    nightcruiser New Member

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    When it dies out on the hill is it because there isn't enough power to pull you and your speed decreases until you are going so slow that it stalls, or does it die out on you when you have good enough speed to stay running if not for being on the hill?

    It could be that the going up a hill puts the carb on an angle that makes it hard to run, you might be able to adjust the float in the carb a bit to eleviate that problem and make it run better when on an angle going up a hill if that is the case.
     
  13. bro-die

    bro-die New Member

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    I took a size 10 socket to confirm and it is a size 10.

    It loses speed. i think its ust because im too heavy and the hill is not that steep but the weight factor. Thats why I asked how to make these suckers go faster so I can zooom fast from the bottom and maybe with a multi speed bike I can down shift at the same time (if you can downshift). Overall its a fun bike I never thought Id go back into my childhood years and have fun with these things.
     
  14. Greg58

    Greg58 Well-Known Member

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    Don't give up it will get better, I thought it looked like the bgf kit I built.
     
    #34 Greg58, Dec 25, 2011
    Last edited: Dec 25, 2011
  15. Nashville Kat

    Nashville Kat Active Member

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    .santa.santa.santa.santa

    Get a short aluminum billet intake to improve carburetion and motor performance- under $20 shipped

    You may also want a newer 66 speed carb- also about $20 shipped- look for shutoff valve on the carb and the word "Speed" or "66 carb" in the ad- it's got a bigger bowl, a bigger port area and a larger jet to let in more gasoline. But the billet intake really makes a bit more difference if you have to choose

    Narrow tires will give you a better roll, a lighter bike and less vibration- you can get 26" all the way down to 1.25 inches these days, but those are rare and more expensive. An older !.75 style tire is out there that doesn't cost much and has a nice road tread for a decent roll, or more expensive and generally smoother 1.50 tires are more polular with all cyclists these days . If your rims are alloy and not steel- the general rule is probably look for tires with the size described in decimals like 1.75 and not fractions like "1 3/4"

    I've got narrow 27" and 700c tires on my two cruiser builds, generally about 1 1/4" wide- like an older ten speed road bike, while I use a modern lightweight cruiser frame for motor, tank and chainstay clearances

    http://motorbicycling.com/showthread.php?p=351395
     
    #35 Nashville Kat, Dec 25, 2011
    Last edited: Dec 25, 2011
  16. nightcruiser

    nightcruiser New Member

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    I think the consensus then is that you probably have a BGF 48cc motor there...
    Does anyone know if a BGF 66cc has 10mm nuts on the head studs, or larger? (Cause the 10mm head studs is what is making me guess its 48cc)

    I know what you mean about feeling like a kid again on these bikes, it's just too much fun! Keep it up, she will run better as she breaks in, and better as you move to the regular fuel mix. After riding and tinkering for a while you will get the hang of it and will probably find several ways to increase your speed and ability to pull up hills.
     
  17. tim turbo

    tim turbo Member

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    I have a BikeBerry black 66cc motor I bought three years ago, and it has 10mm nuts on the head. So I don't think head bolt size is a very good indicater of displacement. The motor looks like a 66cc, with the square head, my 48cc has a some what smaller head that is more rounded looking. Just my 2 bits on the subject!
     
  18. Greg58

    Greg58 Well-Known Member

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  19. Sgt. Howard

    Sgt. Howard Member

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    Regarding that hill- in Tonasket, there is 4rth street going from main uphill to the high school. We live in a ravine that is called a valley- you go either direction perpendicular to the river and soon you are going uphill. Unavoidable. The aforementioned 4rth street is right on par with the best San Fransisco has to offer for 6 blocks. My rig is a monospeed Cranbrook with a 48cc motor. I am 57 years of age with a heart attack 4 years ago on the 23rd of this month, weighing in at 200 pounds.
    I can make it to the top without stalling.
    Wasn't the case at first... it became a challenge to me. Took me a while to master it, but persistance paid off... leaving me to look like a rather STUDLY senior citizen! My wife was born the same year I got my first FFL, 1975- I had just turned 21 that year. Oh Yea, Mama Likes!!!! Mama Likes her washboard!!! You're concerned about weight? It ain't the calories you put in, it's the calories you do or don't put out! This bike is your ticket to a new body- make good use of it! Trust the Old Sgt. on this one or I'll come over there and drop you for pushups!
    Gregory F. (the Old Sgt.) Howardusflg
     
  20. nightcruiser

    nightcruiser New Member

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    OK, so maybe the consensus is that the motor he has is older (manufactured a while ago) rather than being a 48cc (since the head bolts are 10mm). I just started this hobby this spring, and all I have seen are newer motors manufactured in 2010/2011, they all seem to have larger head studs than exhaust/intake studs.
     

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