First build

Discussion in 'Motorized Bicycle General Discussion' started by Rusty_S85, May 4, 2017.

  1. Rusty_S85

    Rusty_S85 Member

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    I have been wanting to start a project lately that will give me something to do that doesn't exactly break the bank like my restorations I am doing.

    I am really wanting to build a vintage looking motor cycle, I'm talking early Indian and Harley Davidson style engine equipped bicycles. I found a fairly close looking frame that could pass for this build over at Kings Motor Bikes for $130. Only thing is I looked on their site and I couldn't find any front forks. Id preferably like to get some front forks that are sprung to make this a little easier to drive on the street.

    The other thing is I cant exactly find any fender listings for this frame surely there is a way to place fenders on these frames.

    I am very new to this so if anyone can offer any help Id greatly appreciate it.


    ~Update~
    Ive been doing some reading in the last hour or so and I see that Kings Motor Bikes have a bike kit for $499 that comes with everything minus the engine. Only thing is I was thinking of piecing the bike together but now I'm not sure what would be more cost effective.

    https://www.kingsmotorbikes.com/col...zed-bicycle-diy-bike-only?variant=14460941572

    The above is what I am looking at. But I am not sure if the drum brakes would be enough for me. I also don't care for the seat style and the handle bars I might change out as well.

    So far my list of what I am looking at doing is as follows.

    GT Frame
    Double Springer Fork
    160mm Front and Rear Disc brakes (not sure if the drum brakes including with the kit above would be enough for stopping the bike with speeds up to 30 mph)
    12v Generator (want to run a vintage style headlight)
    30mm dual air intake pipe (not sure on this thinking I might do this as I am leaning towards doing a high compression 2 cycle build)
     
    #1 Rusty_S85, May 4, 2017
    Last edited: May 5, 2017
  2. crassius

    crassius Well-Known Member

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    lots of folks doing that - at least 6 or 7 years worth of pics of those biles on web and here

    try a search for "80cc board track racer bikes" on google
     
  3. Rusty_S85

    Rusty_S85 Member

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    Thanks for the reply. I did some searching at photos and see that a lot of those are built as racing style bikes but for the most part they are what I am looking for style wise.

    Looks like they are all using the GT style frame I found on Kings Motor Bikes website. Only thing is I need to figure out cause I see the same frame on other sites but the sites say different engines are acceptable as fitting. I don't think I am going to go all the way to 80cc think I will stick around the 66cc I keep finding but some sites say 66 will fit this GT frame and others are saying the 66cc will not fit.
     
  4. Potato_In_Exhaust

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    I say look around Craigslist and piece it together yourself. You will save money, and at the same time have a bike that's not the same as everyone else's.
     
  5. Rusty_S85

    Rusty_S85 Member

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    That's what I am thinking of doing I think if I shop around I can get the pieces I need for less than buying the kit.

    I know I want this frame. I also want those double springer forks. But I don't care for the handle bar setup nor the pedal setup that it comes with.

    Only thing I am looking at right now is engines still. I also might need to do some searching on here for headlight mounting.
     
  6. Rusty_S85

    Rusty_S85 Member

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    Well this morning I did some reading on springer forks. Was going to get the ones from Kings Motorbike but say on Bicycle-Engines that they make the real frame for $170 and im thinking the $130 one from Kings is a knock off. With that said i started reading on double springer forks and been finding conflicting stories on how horrible they all are.

    So what brand should one go with on a motorized bike that would be safe and not fail?

    I prefer bare metail or painted with chrome accents as ill be stripping and painting the forks to match the rest of the bike.

    Only thing is ive read on Monach and heard they are junk. Heard the Monarch II are just improved junk. Then Cuda i was reading was the go to one but the disc brake caliper mount is on 5he fork itself and causes the bikes front to lift up when braking.

    So what really is a good double springer fork for the money that is durable for speed?
     
  7. crassius

    crassius Well-Known Member

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    few that I see use other than an underslung frame in which they pack a round metal section to look like the bottom end of an old long-stroke motor - some even mask the barrel of the 2-stroke with a long head or head cover that looks like the tall barrels of the old motors
     
    #7 crassius, May 5, 2017
    Last edited: May 5, 2017
  8. Rusty_S85

    Rusty_S85 Member

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    I was actually looking at one of the tall high compression heads as it would increase the height of the engine to give it more of a retro look.

    But I found a low profile high compression head that also looks very vintage.
     
  9. Rusty_S85

    Rusty_S85 Member

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    Ive been doing some reading today and for some reason I gave a look at 4 stroke engines mainly because Ive seen it stated numerous times that these 2 stroke engines need cylinder replacements once a year if you drive a lot. Well I want to build a driver to use quite a bit so I started looking at 4 stroke engines.

    With that said on a few motorized bicycle sites I found the Predator 212cc 4 stroke engine as the only 4 stroke sold in kit form for bicycle application.

    Now I do like the idea that you have valves and can hop the 4 stroke up easier by changing parts and timing without having to actually do grinding on the cylinder like with a 2 stroke. Only thing is I didn't find much on here in the ways of using the 212 Predator engine.

    Ive seen it stated frames cant handle the stress of the 212 Predator, well I wont be using a stock bicycle frame bought off the shelf at a bicycle store or academy or Walmart. I'm looking at the frame below for my build as I hate the look of the bolted on fuel tank look.

    http://www.bicycle-engines.com/Grubee-Aluminum-Motorized-Bicycle-Frame-GTA.html

    That is the GTA with the curved frame but they have a GTS with a straight frame built for use with 4 stroke engines. Same price but slight different design.

    Only thing is I see difference of opinion. I see lots of people saying you have to run a jackshaft and use your bikes multispeed gear set while others say you could use a single speed set up, so what is it? I looked on here but couldn't find much in the name of people doing a 4 stroke setup and I have done some searching online didn't find much either unless I just am not doing a search with the right words.



    Never mind, I did some more reading and while its doable with a 79cc Predator I really don't want a multi speed bike for the retro vintage look I am looking for, I also absolutely hate the fact you have no manual clutch and you have to pull start this. Guess I will just stick with the 66cc two stroke china engine and just try to build it up as best as I can and limit cylinder mods since from what I hear ill be replacing them more than I do spark plugs.
     
    #9 Rusty_S85, May 6, 2017
    Last edited: May 6, 2017
  10. crassius

    crassius Well-Known Member

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    the 2-stroke is a disposable motor - I have customers that ride WOT only and replace the motor in 20 minutes or so twice a year
     
  11. Rusty_S85

    Rusty_S85 Member

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    I figured it was a disposable motor. I kind of want something that would last a bit longer but I guess could always just keep a spare cylinder and piston and just swap it over when the time comes.

    Its just for me I can do more tuning a engine with valves than I can with a two stroke. I did do a lot of reading on tuning one and the farthest extent I would go is adding an extra gasket under the cylinder to raise the exhaust to increase timing on the exhaust side. Down side is this also decreases timing on the intake without grinding.

    I guess what I need to just do is figure out the basis of the bike first then go from there.

    I know I want to go with the Grubee GTA frame with the curved down tube. It has a vintage look to it to me compared to the straight tube.

    Now I need to decide 135mm or 150mm wide frame. I know I want to go with double springer forks up front but I want to have the forks able to be disassembled to be stripped of paint and painted to match the frame. I also would like chrome hardware so only way for something like this is to go with the Monarch II double springer fork and hope like **** the chrome trim is removable so I can remove the black paint and color it to the frame. Then have to figure out the whole 1 1/8" vs 1" headset. Part of me feels that a 1 1/8" headset would be more durable than using an adapter to fit a 1" headset springer fork to a 1 1/8" headset frame. But I need to know this to figure out what width tire I could run so I can run the same size front and rear.

    Maybe I am just making this harder than it has to be. But only thing keeping me from ordering the Grubee frame right now is the 135mm vs 150mm width.
     
  12. Kletus

    Kletus Member

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    If they ever offer one that has a flat plate engine mount that will accept a Predator or Honda 4-stroke engine I'll jump on it.
     
  13. Rusty_S85

    Rusty_S85 Member

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  14. malatious

    malatious Member

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    There is also the 79cc and 99cc versions of the predator engines. They are a little smaller and easier to fit in the frame. Also, they have much less torque and would cause less stress on the components. The 79cc and 99cc engines don't have as many after market parts available for tuning but they are starting to show up. affordablegokarts.com has some stuff. Also, the 18# springs for the 212cc will fit in the smaller engines.
     
  15. Rusty_S85

    Rusty_S85 Member

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    Does the 79cc and 99cc versions of the predator engine have the ability to use a manual clutch?

    That was the big reason why I moved away cause I thought there might be a way to convert it away from pull start but make it a crank start like the 2 stroke but couldn't find anything on it.
     
  16. Potato_In_Exhaust

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    Go with the 2 stroke..... lighter, twice the power (theoretically), and nothing like the feeling of a 2 stroke when it hits the pipe! It's a myth that 2 strokes doesn't last long, as long as you don't over-rev it all the time, they can be pretty damn reliable. I've taken mine out on 2-3 hour long rides with hardly a break in-between and it hasn't let me down yet..... and I've ridden it a lot and hard.
     
  17. Rusty_S85

    Rusty_S85 Member

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    Well that's good to hear. Considering my first build is going to be a retro build I have been leaning towards the 2 stroke just because it has a vintage look to it.

    Its just ive read a few times now that you shouldn't run a 2 stroke more than an hour at a time with a half hour cool down and a 4 stroke no more than half an hour at a time. Thought that was kind of strange. Ive ran edgers longer than that at a time.

    But it looks like I will be running this engine stock at first to break it in then start making some changes to it. I found a piston and cylinder kit for $80 that is a ported design that I might give a try later on. Long as I can obtain 20 to 30 mph cruise speed without over reving the engine I will be happy.
     
  18. malatious

    malatious Member

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    I'm in the process of building a bike with the 79cc predator with a 3D manual clutch. You have to put a sleeve on the shaft to adapt from 5/8" to 3/4. My engine was from a water pump which required some additional fabrication to get it to work. I'm in California so I can't just go into Harbor Freight and look since they don't carry the 79cc and 99cc here, but I think I saw someone else with the manual clutch on one.
     

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  19. Rusty_S85

    Rusty_S85 Member

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    Looks great. I might go that route for my second build. I do want to build a boardtrack racer style bike for all out performance might do that as from looking at your build I could easily make a chain guard that mimics the original style guard from the old Indian bikes.
     
  20. Rusty_S85

    Rusty_S85 Member

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    Well after all the problems I had with RawMotors I got my money back this previous Friday, my bank refunded the money to me since I couldn't get a hold of the owners or anyone.

    Needless to say I purchased Saturday the same frame from another place and already as of today got a confirmation they are processing my order around 9:30am and as of now I have a FedEx tracking number and will have the frame Friday. Now I just need to get some cash put to the side for the springer forks and then I can start stripping the forks down to bare metal and painting everything.
     

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