Lurking Newb, looking to build first bike.

Discussion in 'Introduce Yourself' started by ImpulseRocket89, Apr 19, 2014.

  1. ImpulseRocket89

    ImpulseRocket89 New Member

    Howdy folks, I've been "thumbing" through many posts and following many links for modifications on the little china girl kits for my bike. The bike is actually a Schwinn Clarimont that I bought 2 years ago after a back injury and surgery that put me down for almost 2 years as a means to get myself back in shape (well, relatively anyway). I have always wanted to build a moped like bicycle, and a buddy directed me to some of the kits out there, and well....decided to do it. I soon found out that the bike I bought turns out to be a pretty good starter bike for doing this stuff, so bonus!

    I'm a not quite middle aged (early 30's lol) NFL Lineman sized guy ( 6'5 310lbs ), so I have interest in doing some mods to the engine in question to kind of bump it's power to haul my big butt around with. Yes, I will probably look goofy on it, but I never cared what other people think anyway. I am not looking for a speed demon, and would have no problem with topping out around 30mph, which is also the legal speed limit for a moped before it is considered a motorcycle in my state anyway. I figure if I use a jackshaft kit and utilize the bikes 7 gear shimano cluster, and build the bike with less focus on top end/high speed stuff I can get there. Money is really no object as far as doing what I have to do to make the build happen, but I also don't like wasting money....which is why I have been reading so much.

    That being said, I am always open for suggestions or advice from people that know more, so by all means, leave opinions. The whole point of this bike is to give me a fuel efficient way to get to and from classes, since I am a returned college student thanks to my back injury. Since bouncing around in a truck and doing physical labor jobs is out of the question, I am finishing what I started with my mechanical engineering degree.

    Warning, forgive gratuitous showy offy car pictures. I love my cars, and well.... Let's just say I have a heck of a lot more pictures than this. :whistling:

    For a little more background on me, I am also no stranger to custom fabrication, and I am a bit of an oddball car lover and speed junkie. I am currently in the process of building my 1988 isuzu Impulse as a track car with a 4ZE1 (2.6L) engine with a fully built short block using custom pauter rods and JE pistons and an EFR 7670 Turbo. A couple of teaser shots :grin5:
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    I also have a 1988 Jeep Comanche Pioneer 4x4 4.0L that is a partial project truck/daily driver. Not really much to show with it right now, but I've replaced about half of the driveline at this point. and almost all of the suspension.

    [​IMG]

    Oh, and of course, my actual daily driver, 2005 Crown Vic. Mostly suspension mods, so it's still slow, but it takes a corner like crazy. I claim no ownership of that Explorer. I didn't pick it or want it, and it's in my driveway anyways.... You can probably do the math from there lol

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    Otherwise, this is a pretty informative site with a lot of good information on it, and I look forward to future forum shenanigans.
     

  2. bluegoatwoods

    bluegoatwoods Well-Known Member

    Welcome aboard.

    I guess I'll start with a bit of bad news. Your back injury worries me. These bikes give a hard ride. This doesn't necessarily mean that you can't do it. But you'll have to be careful. Front shock forks plus a shock mounted seatpost is probably the place to start. Then if you can learn to ride the bike the way you might ride a bucking bronco, and I'm only exaggerating a little bit, you should do okay.

    I'd also consider keeping your speed hopes a bit lower. For the sake of your back and your bike.

    But don't let me be discouraging. I'm one of those folks who are always saying, "Slow down!". And I think I'm right, but there are people who seem to get away with some speed. But these bikes are a lot of fun. And you might well be able to ride faster than I think you can. Just be aware that it might take a little doing and some practice.

    Good luck and have fun.
     
    ImpulseRocket89 likes this.
  3. butre

    butre Well-Known Member

    I slipped a vertibrae when I was around 12 and have had proper back pain ever since. A suspension seatpost helps.
     
    ImpulseRocket89 likes this.
  4. ImpulseRocket89

    ImpulseRocket89 New Member

    Hi Bluegaotwoods. Yea, I have taken my back into consideration. I can actually get my bike going at a pretty good clip with my own legs, and some jolts are definitely felt. I was looking at various springer front ends, but I don't think I have found any that will work with the front of my bike. I would like to add some suspension, but.

    As far as speed hopes, like I said, I am not after a speed demon. When I say 30-35, I am talking absolute most. I want to build a more powerful motor so I can get up to speed and climb hills easier. I have no care, need, or wish, to go blazing around at 40+ on a bicycle. They are already scary enough approaching 30mph going down a hill. I would honestly be perfectly cool with cruising along at 20 and have the ability to climb some of the bigger hills around here more easily. The other practical side of it is, Johnny Law won't look at me while I toodle along at 20ish MPH, and I like the idea of not giving the police a reason to stop me and give me hell.

    Buture, I was a lot more lucky (if you can call it that) in some regards. My back injury was actually a severe herniation on the right side of L4-L5 that did not recess properly. That disc, and my L5-S1 both have Severe formial stenosis, aka, there isn't much left there, and what is there is very weak. That's why it herniated in the first place. Between those two problems, the nerves to my right leg were severely compressed and it made my leg useless. Unfortunately, even though the surgery (Laminectomy L4-L5, L5-S1 on both sides, and Discectomy (herniation removal) took the pressure off of my nerves, I still have a lot of nerve damage due to the amount of time that they were being crunched on. The bike worked well enough to help me get in some shape, but I ended up not riding because I have a problem with random muscle twitches and cramps in my major muscle groups. The more I exert said muscles, the more weak and prone to these problems they become, and it makes peddling a bike very hard. This is one of the big reasons my buddy suggested motorizing it to get around, as I had tried to use it to ride to classes to save on gas (I only live about 5 miles from the school I attend) was because of the problems I have. I could get to my school just fine, only to arrive and have problems walking and standing, or having painful cramps that made it very hard to concentrate.

    I will definitely consider a suspension seat, along with a front suspension set of forks if I can find some that will work, as a way to minimize bumps though. Thanks for the advice.
     
  5. LR Jerry

    LR Jerry Well-Known Member

    You may want to consider a recumbent build.
     
  6. ImpulseRocket89

    ImpulseRocket89 New Member

    I'd love to, but seeing as I already have this bike I think I will just go forward for now. Most recumbent bikes are pretty darn pricey too, which defeats the purpose of building my bike to be more economical.
     
  7. butterbean

    butterbean Well-Known Member

    I will suggest something for you to consider. I have a similar build as you (6 ft 2, 285). The china girls are ok, but running them stock you won't get enough power to make you happy. You can mod them, but those little engines are a crapshoot to begin with (meaning some of them are reliable and some aren't, right out of the box they can have problems, and keeping the good ones reliable depends very heavily on the builder's mechanical as well as tuning skills). With your back condition, I gather you don't want to spend a lot of time wrenching on your bike after it is put together. So let me just suggest this, and you think it over. A large displacement 4 stroke will cost a little more to put on a bike, but it will pay for itself with reliability and performance right out of the box. Remove the governor and gear it for your needs, and you will have the power you want without having to do anything extra to the engine. I am currently running a used minibike engine, which is an option but going to run you about $150 on ebay after shipping costs. I myself am planning to upgrade to a 79cc Predator engine, which will run you about $100 plus $6 shipping if you don't have a local harbor freight store to pick it up. There are no kits available with these engines, but there are bolt-on parts available. A motor mount and jackshaft (not like the ones for the 2 strokes, keeps the drive chain on the left side of the bike) will run you about $200 or so, then you will need a throttle and I recommend a sprocket adapter and billet sprocket, but altogether including the engine should be under $400. As long as you install everything correctly, maintenance is minimal (change the oil, put air in the tires, check chain tension and make sure all your cables are working properly) and you're riding. With the 2 strokes, it is possible to put them together and build them real solid, but they can still end up with problems. With the 79cc 4 stroke, just don't over-rev it and you're fine. I recommend getting a tachometer (tells you what rpm you're running, I don't have one yet but I plan to before running the 79cc) and don't go over 5500-6000 rpms. As I said, just a thought but worth considering. The only problems I have had with my current 4 stroke engine/bike were due to my own errors. The engine has been reliable from day one and typically starts on the first pull. Another advantage of a 4 stroke is pull-starting (no pedaling and releasing the clutch). You will need very wide cranks, and may have to heat and bend them yourself. I bought a mapp/pro torch at lowes for $50 (yellow cylinder) and did it myself. Heat in one spot till red hot, bend outwards, heat at another spot and bend in. This keeps your pedals at a 90 degree angle to your frame, but makes extra room for them to clear the wide engine. It's a lot to digest, but the bottom line is that I think a large displacement 4 stroke will give you the performance and reliability that you'll no doubt be wanting.
     
  8. Mr.yup

    Mr.yup New Member

    Hey, could you get me a list of the parts you'll be getting for the predator? I'm looking at using that engine for my build on a Schwinn cruiser bike.
     
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