BGF engine questions

Discussion in 'Motorized Bicycle General Discussion' started by SavageBlunts904, May 23, 2012.

  1. SavageBlunts904

    SavageBlunts904 New Member

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    I just found a decent deal in town for a BGF engine and its not labeled at all and neither was the instructions for how big the bore is. It seems to look the same size on the outside as my 48cc Skyhawk but im not sure. Is there any way to figure out the size without taking the head off of the motor?
     
  2. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Most of the 50's I have seen look marginally smaller than the 66-7cc's.

    How do you know it's a BGF if it has no markings?
     
  3. SavageBlunts904

    SavageBlunts904 New Member

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    The guy i bought it from said he got a deal on a nice supply of his kits. It also comes with BGF install instructions (which arent needed) but i am not sure about the size. Info kina needed for legal reasons ya know. Im sure once i get my wheel in ill be able to tell once i break it in. If it sucks i still have my china girl sittin in a sealed box thats good to go. Only difference i see on the motor is a different clutch puller and a flat head, the china was a slant head.
     
  4. Al.Fisherman

    Al.Fisherman New Member

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    China girls came in both flat and slant head. Check the cylinder studs, if the nut is a 14mm, then the studs are 8mm, and most likely a 66cc. Although there are a few 66cc engines that have 10mm head nuts, or a 6mm cylinder stud. Different kits come with the straight and angled clutch lever. All my engines (6) are 66cc and I have both levers.
     
  5. Greg58

    Greg58 Well-Known Member

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    That sounds like the bgf 50 I have, no markings what so ever. You may want to check to see if the piston clears the port on the intake side at tdc, on mine the plston blocked about .250 in in the center of the port. I removed the piston and did the mod. found in the performance section of the forum and that really helped that engine a lot.
     
  6. Greg58

    Greg58 Well-Known Member

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    If this helps there was a white box inside a standard cardboard box, all the box has on it is BGF and Z50.
     

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  7. dragray

    dragray New Member

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    who cares what it it?
    if it's a good deal, and it's brand new, buy it.
    to be honest, my 50 c.c. 2 stroke will outrun my 66 c.c. (i bought them both from bgf and both of my bikes are set up very similar to each other).
    my 66 vibrates liek crazy at w.o.t., but my 50 is as smooth as silk.
    legal reasons?
    no one can tyell what size it is unless they take it apart and measure the bore....no cop is going to do that.
    If anyone asks, ust say that it's a 50, no one will know unless they rip it apart.
     
  8. Greg58

    Greg58 Well-Known Member

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    I care, the laws are for a reason.
     
  9. Greg58

    Greg58 Well-Known Member

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    I don't think anyone here should suggest someone break any laws "HONESTLY ".
     
    #9 Greg58, May 24, 2012
    Last edited: May 24, 2012
  10. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Never say never....it would only take a LEO 5 minutes to pop the head off and measure. They have done much more complicated jobs to assure truckers are obeying the laws.

    They used to run us down on our murdercycles and go through all kinds of thorough checks when they felt the need to do so.
     
  11. 2door

    2door Moderator
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    It's never a good idea to suggest that someone intentionally break the law.
    That said, it is a fact that the Chinese 2 stroke engines are so similiar in outward apperaance that the only way for a a law enforcement officer, or anyone else to be sure about the displacement would be to removed the cylinder head and accurately measure the bore and stroke. I feel this is something that few would ever do due to the specialized equipment necessary.

    Nevertheless, if you want to be certain that your case would stand up in a court of law, if it ever came to that, is to keep the engine displacement under, or at the legal limits for your local. That way you have facts and the law on your side.

    Tom
     
  12. dragray

    dragray New Member

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    really?
    holy cow....sounds like some people worry too much.
    not that breaking the law is a good thing, but seriously, this is a bicycle engine, not a 1000 c.c. streetbike diguised as a 250.
    I guess i'm glad that i live where i do because i don't have to worry about this sort of thing.
    heck, here, people ride 4 wheelers and golf carts on the streets.
     
  13. Saddletramp1200

    Saddletramp1200 Custom MB Buiilder

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    If you mess up so bad the cops stop you, the size of that little motor won't matter. (c)
     
  14. rustycase

    rustycase Gutter Rider

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    I'm all for going to court and getting these little personal transport things recognized as being 'below the radar' but I also feel it would be very wrong to tell anyone they are not going to have encounters with the enforcement people if they choose to ride one.

    It will happen.

    The outcome of that event will depend on many variables, least of which being a minor difference in displacement.

    Good luck
    rc
     
  15. landuse

    landuse New Member

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    People worry because there are some guys and gals ou there that have motorised bikes as their only means of transport. If people go about breaking the laws regarding these little engines, the law is going to change and all motorised bike engines are going to be outlawed.

    So stick withing the law, and they won't become illegal. Have a thought for those that use them as their only means of transport
     
  16. crmachineman

    crmachineman New Member

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    Totally dude, I agree! Damn this kind of thing really shouldn't be on anybodies radar. I actually think there are a few legitimate problems with these restrictive laws. Suppose you are a full grown adult who needs to safely go to work or to the store.... If you need a little more engine displacement to safely transport yourself, I don't think anyone has the right to make it illegal to do so. I sincerely believe that low speed bicycles are in greater danger than a bicycle that can keep up with traffic. Personally, I try to get as much speed as I can, so I don't have dozens of cars passing me on the left. What if someone in a car is talking or texting on the phone, and happens not to see the poor bicyclist riding on the shoulder?
     
  17. maurtis

    maurtis New Member

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    Sounds like the need for a scooter or small displacement motorcycle, then. Better brakes, better suspension, more speed... My wife's Vespa LX150 was a pleasure to ride to the store and back, it would barely hit 60 so was not suitable for the freeway, but was a treat as a grocery getter.

    If you want to stick with a motorized bicycle, maybe a high HP Morini, or the DAX KTM clone, and some front and rear disk brakes? That should be at or near the displacement reqs of most states, but get you moving with the flow of non-freeway traffic pretty good.
     
    #17 maurtis, May 25, 2012
    Last edited: May 25, 2012
  18. multipaul

    multipaul New Member

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    Push a kind of ruler without sharp edges into the exhaust. Less than 70mm should be a <50cc engine.

    I hope that helps.

    Multipaul

    [​IMG]
     
  19. maurtis

    maurtis New Member

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    That is a fantastic tip!
     
  20. Dan

    Dan Staff
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    It is!

    I always wondered how many China girl's cc's actually matched what was printed on the box. Not to cast aspersions. Just never got around to measuring one but am pretty sure I got a few that were mislabeled.
     

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