My first build. Need some advice and I have some questions.

Discussion in 'Motorized Bicycle General Discussion' started by Herdo, Sep 24, 2013.

  1. Herdo

    Herdo New Member

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    Hello everyone! I am currently planning out the construction of my first motorized bicycle and I have some questions I am hoping you all can help me with.

    First, I should start out with the parts list and go from there:

    Schwinn straight bar frame: $150

    Monark II Forks: $200

    Crankset: $50

    Handlebars/Grips: $60

    Saddle/post: $50

    26" 2.125" 12 gauge steel rims: $40

    12 gauge spokes: $25

    Sturmey Archer S30 3spd hub with drum brake: $90

    Sturmey Archer XL-FD 90mm Front Hub OR X-FD 70mm Front Hub: $75

    Quick Brick black tires: $60

    Extra/Misc: $50

    Total bicycle build (pre-motorbike addons): About $850



    Motorized addons:

    HuaSheng 49cc kit with 4G belt drive 5:1 ratio: $400

    SBP Shift Kit: $200

    Custom gas tank: $300

    Total motorized addons: $900


    Total cost: $1750 give or take $100 or so

    Minimum cost (if I put the SBP shift kit and custom gas tank on hold for now): About $1250



    Now, that is a lot of money, maybe too much. I plan on commuting on this bike 3 days a week 11 miles each way. So let's just say 75 miles a week or 3900 miles a year which we will round to 4000. I've read on several threads here that I should be able to get 4000 miles out of my motor with regular maintenance and upkeep fairly easily, and even if I had to replace the motor and shift kit annually, I would be happy considering I spend at least double that on gasoline annually as it is.

    In Arizona, the law states that motor assisted bicycles must be driven below 19 miles per hour. I don't plan on going over that. I'm serious! One of the great things about living in the Phoenix metro area is that everything is on a grid, and my entire 11 mile ride to work can be made using entirely residential side streets. I honestly don't plan on riding over 15 - 20 mph hardly ever, so wear and tear on the bike should be kept down.


    Overall, I am looking to build a bike that will last quite a while that will be very durable.

    That being said, is there anything I am overlooking or forgetting? Also, is there anything that I am maybe over doing? I'd like to save some money wherever possible on this, but I'd also like to have a safe reliable bike with some style.

    I have a question about the 90mm hub. I read in a thread here that someone mentioned having to get custom 12 gauge spokes for their 90mm Sturmey Archer front hub. I'd like to avoid this if possible, so would the 70mm work fine for my purposes? Like I mentioned previously, I don't plan on riding faster than 20mph at the most. Also, if anyone has built a bike using 26" x 2.125" rims with the 70mm hubs and 12 gauge spokes, could you tell me what rims and spokes you used? I'd like to be able to buy the correct parts to take to a bike shop to have them assemble and tune it. I've heard taking just the rims and hubs to a bike shop with them supplying the spokes costs an arm and a leg so I'd like to just buy all the parts on my own, but I have no idea what is fits together.



    One final question; with the 4G T belt drive, should I look for the 100T (5:1) or the 80T (4:1)? I have read several comments where people recommend the 100T, but I am unsure what the actual difference is.


    Thanks for taking the time to read this, I know it was lengthy.
     
  2. mapbike

    mapbike Active Member

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    well I read every word here, and I can say that I have no experience with the engine you are looking to use, I don't have any of the fancy hubs you mentioned and I don't have a bike with a shift kit, but what I do have are three very dependable bikes.

    The fact that you are wanting to do such a complete ground up build, I'm hoping you have a good selection of tools and plenty of mechanical experience to get it all done right, personally if all I ever intended to go was 15-20mph Id just order a friction drive setup from Dax and be on the road in a couple ours and just honestly keep it that simple.

    with what you are wanting to do, you should have a nice dependable bike, but most of these little engines build there power under the higher RPM range so if I were wanting to just put around at 15-20mph i would put as big of a sprocket on the back wheel as I could, but then again as I said earlier, I have never used the little 50cc 4 smoker engines so I really am not qualified to tell you 100% what would be the best set up for what your wanting to do, all I know is that there would be no way I would spend all that money on a bike to only go 15-20mph... but hey just like it has been said in the past here.. " it's your bike, build it the way you want it"

    sorry I cant help you with the questions you ask, but I just wanted to ring in here and let you know someone is reading the post and at least has some sort of opinion regarding the build plan you have laid out.

    best wishes and I hope you can get it to where it just what you want it to be.

    map
    reddd
     
  3. curtisfox

    curtisfox Well-Known Member

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    What a awesome start, them engines are baseikly the same as a Honda GX50. So it should last a long time...............Welcome aboard.............Curt
     
  4. Herdo

    Herdo New Member

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    Thanks for the replies! I know it is quite excessive and I did originally plan on just getting a friction drive kit and a used bike off craigslist and calling it a day. I do realize that I am eventually going to want to upgrade to something more stylish though.

    I without a doubt want a custom tank on it, and that is where I started. Obviously to mount the custom tank I am going to need one of the Schwinn straight bar frames, which isn't a huge deal because they aren't too expensive.

    From there, it's just a matter of do I want to buy something cheap now knowing I will want to upgrade it soon anyways?

    Take the forks for example. I could definitely get myself some cheap "Schwinn Style" springer forks for $50, but I am not sure if I want to be riding on those 75 miles a week.

    That is the question though. Am I overdoing it? Will some cheap "Schwinn Style" forks work just fine?

    I am definitely going to hold off on the custom tank and shift kit till later. I've also decided that until then I can just use a coaster brake on the back. I've found this seller http://custommotoredbicycles.com/sta-tru_heavy_duty_bicycle_wheels_26_inch_x_2125_assembled_in_usa_better_chrome who offers a 26" x 2.125" front tire with the Sturmey Archer 90mm drum brake and 12 gauge spokes and a rear wheel with a coaster brake for less than $200. That will save me some money.

    I'll probably rework some of these numbers, haha.

    Also, it should be noted that I am going to be selling my motorcycle so I will have a few thousand to spare.
     
    #4 Herdo, Sep 24, 2013
    Last edited: Sep 25, 2013
  5. bluegoatwoods

    bluegoatwoods Active Member

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    Welcome aboard. Don't worry that your post was lengthy. We like posts that contain plenty of precise info, for that matter. You did just fine on that.

    The bike you've described will be fine. There's no doubt about that. But I'm also wondering if you might be better off starting with something more modest.

    Your riding conditions sound almost ideal. The only downside I can think of is that you're likely to be dealing with a lot of stops and starts if you'll be riding entirely on residential streets. So you might want to go with a larger than normal drive sprocket. Or roller, if you go friction drive. To get the most low speed torque.

    The bike you described above will likely be plenty up to the task you're describing. I'm only a bit concerned that you might spend $1200 or so only to find that the bike doesn't quite please you. If you find that you don't like, for instance, your stance then that might be enough to make the bike not good enough.

    So why don't you consider doing a $400 build? Maybe a china girl engine and 48 or 50 tooth drive sprocket. Maybe a friction drive. They both ought to be able to handle a Phoenix residential commute. You'll get practiced at keeping these things up and running. Then when the day comes that you want something higher-grade, you'll have more experience. Then you'll likely know exactly what you want.
     
  6. mapbike

    mapbike Active Member

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    You read my mind on the points you made here, spend the little bit extra maybe on getting a better wrist pin bearing and better KMC415H chain and then if you go with the right china girl kit you will likely have a very dependable ride, in my experience a 44T sprocket gives loads of low end power on a well tuned china girl bike and will cruise at a comfortable RPM at 20mph.

    Map
    reddd
     
  7. xseler

    xseler Well-Known Member

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    That's a **** of a first motorized bike!! Looks like you've done your 'homework'....

    Welcome to the forum!!
     
  8. Herdo

    Herdo New Member

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    You guys are absolutely right. I should get myself a cheap 2 stroke and strap it on the old rusted out Huffy Cranbrook I have laying in the backyard to see if I even like it.

    So I guess the only question I have left is, where is a good vendor to buy the 48cc Chinese 2 strokes from? I know the engines are all pretty much the same, but it seems like a few places offer extras or upgraded pieces.

    Thanks everyone, I'm thinking I could probably get something up and running in the next month or so.
     
  9. southpier

    southpier New Member

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    I don't make believe to know doodily about motors & bikes, but I do understand the value of customer service.

    whichever way you choose to ride, it might not be a bad thing to have a local bike shop in your corner. I know first hand some of them are a little difficult with which to deal - just like their customers! - but when you get on board with a good one, it can be a real trove of knowledge and save you some time & headaches.
     
  10. chainmaker

    chainmaker New Member

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    I'd say rethink what you want to do, you went from a pretty good plan of attack on a nice 4 stroke build to a rusty cranebrook build in less than 24 hrs.
     
  11. Herdo

    Herdo New Member

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    Thanks guys.

    Southpier, good point. There are a couple local dealers around me actually who sell the 48cc 2 strokes, I will look into them.

    Chainmaker, I agree, I am a bit confused. I do think bluegoatwood has a point however. It makes more sense to go with something cheap in the meantime that I can just put around my neighborhood if anything to see how I like it. I'd rather spend $200 now and realize "Hey, this isn't for me" rather than $1500 later to realize the same thing.

    I should be able to clean up the rusty cranbrook no problem with some vinegar and some aluminum foil (hopefully). I think at most I might have to replace the chain.

    By the way chainmaker, your 47 Whizzer H build is where I got a lot of my ideas from http://www.motoredbikes.com/showthread.php?39369-All-Entries-EZM-2012-In-Frame-4-Stroke-Build-Off&p=352977#post352977
     
  12. curtisfox

    curtisfox Well-Known Member

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    I agree, if you are going to ride it as much as you say. in my opinion the 4 stroke would be a better choice. Smother and quieter just less tempermental...........Curt
     
  13. Herdo

    Herdo New Member

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    I hear ya, and that's why I originally settled on a 4 stroke. Funny thing, my girlfriend and I were talking about this bike tonight, and about my 11 mile commute. We happen to work within 1 mile of each other and we ended up talking about moving closer. We started looking at houses for rent closer to our places of work, and we found several houses for rent right in the middle of our works in our price range that we love. So it looks like in the next 3 to 4 months I will probably be commuting less than 1 mile a day round trip, haha :p.

    Either way, I think for now I will just get myself an engine kit and put it on this huffy I have. I'm leaning towards the 4 stroke, because I can always build on that later.
     
  14. chainmaker

    chainmaker New Member

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    Maybe build up the original plan bike for a 2 stroke, but buy the kit last. I'm betting you will find you like this hobby. And go for a 4 stroke. Thanks for the compliments, I started with a 2 stroke kit and before it was done I was planning a 4 stroke, if you do end up with a 2 stroke don't purchase by price, go with customer service.
     
  15. maniac57

    maniac57 Old, Fat, and still faster than you

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    If you decide on a ring-dinger, I've had great results with mingsinternational and rose326 on e-bay. Over 25 kits with only two bad coils! (which were replaced free)
    About the best prices vs. quality I have found.
     
  16. caduceus

    caduceus New Member

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    Just a few comments:

    1. Always use either locknuts or blue locktite on clean threads. Things will vibrate loose quickly if you don't.

    2. For your first build figure on doing everything three times, and spending about twice the money you originally intended.

    3. Buy the best tools you can afford. Cheap tools always end up costing you more.

    4. There are very few things in this world that are as satisfying as riding around on a motorized bicycle that you built yourself. Have fun!
     
  17. silverbear

    silverbear The Boy Who Never Grew Up

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    That's my thinking, too. For me the difference between a 2 stroke china girl and my first 4 stroke (the one you had on your list) was night and day. Vibration that made my hands( china girl) tingle and vibration free( 4 stroke). Pedal start ( china girl) & using the clutch at every stop/start versus easy pull start and an automatic clutch with the four stroke. I used a different transmission (Q matic), but can say that my four stroke was trouble free, very dependable and I put a lot of miles on it.

    Since money is not really the issue (not that you want to waste it) and you're intention is to use it as serious transportation... I'm wondering how much you want a motor bicycle and how interested you are in building one. If you're not really all that interested in building one... just want the cheap transportation, then if it were me I would buy a new European Tomos 2 speed moped for around $1200.00 and be done with it. As you say, you will have money from the sale of your motorcycle and were ready to spend more than that with your proposed build. Nice looking, fun to ride, capable of 40mph, kick start, economical, front and rear suspension, automatic transmission and well made. Buy it today and ride it to work tomorrow. If something is wrong with it take it to the dealer to sort out. Tomos has been around for a long time. Not Chinese.

    If you really do want to build a motor bike then do it in stages perhaps and then upgrade with your 300.00 gas tank, etc. . Go ahead and get the frame you like (yes, to the Schwinn straightbar!) get your solid wheels and brakes. If you really are only planning to go 20 mph or less then the 70mm drum up front is OK, but if you're going faster than 30 then the 90mm would be better.

    So, you need to do some soul searching and be clear on what you want. I like building bikes and don't mind that it may take a whole winter to build one.

    Whatever you decide, good luck to you and safe riding!
    SB
     
  18. bluegoatwoods

    bluegoatwoods Active Member

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    I'll offer one caution on the Cranbrook: watch out for that rear hub. They are not very good.

    I've had to rebuild mine 4 or times during this summer.

    Other than that, though, the Cranbrook really is a good bike for this job. More stout than I'd imagined.

    Though you might want to switch to a shock absorbing fork as well. A 'no suspension' set-up will beat you to death.
     
  19. MadMannArt

    MadMannArt New Member

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    I have the Monark II front end... If you want to cut a corner or two, don't do it on the front end choice.
    I used to build choppers for a living... When your cheap front end gives out, you will not be standing still....
    From what I have seen shop around, you can find those wheels already built, ready to rock & roll a little cheaper from vendors in the sidebar... or or google them, I have seen them.
    I am crazy, I used a one speed coaster, no other brakes, we called it a suicide set up on a bike. (Do NOT do this set up without riding experience, as it will gain you crashing experience...lol)
    26"slick tire on the rear, 26" Bell skinny street front tire, in a local that rains daily. (I have a death wish :)
    If you want some serious quality look at the EZ Motorbike kit, 600 smakers but looks like a set up for the daily commute that you seek, probably wouldn't need a jackshaft set up on it.... Savings????
    I myself am considering that kit...
    I have a Grubee GT5 that is going to get swapped out for a Dax 69cc 2stroke kit..
     
  20. caduceus

    caduceus New Member

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    I use a coaster brake on both of my current rides. They work far better than the band brake on my first build.
     

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