Decided to build a Motor Bike (But budgets low)

Discussion in 'Introduce Yourself' started by TonyGotSkilz, Jun 20, 2009.

  1. TonyGotSkilz

    TonyGotSkilz New Member

    Ok so i've decided to build a Motorized Bike to commute my 9 or so very hilly miles every day. I haven't ridden a bicycle in a few years (but its like riding a bike right? j/k) but i did own a motorcycle for quite awhile up to a year ago and loved it.

    My budget is only about $200-250 and so far i've seen some kits on Ebay for $120 and i've got someone who will install any kit for $25 so i'm looking on Craigslist for a $50 or so bike. I was just wondering if anyones had any experience with the E-bay kits cause i'm a bit warry.

    I've spoken to a local guy (to San diego) and he has a small business selling these kits and bikes and he says he can sell me the best/faster 80CC motor you can get for $160 and he'll bore out the carbs (cause he says they come with barbs and rough edges on most kits) and add some extra needed o-rings and stuff for that price. He sounds pretty legit, and says he's tested 12 different engines and now thats the only ones he uses (he's made tons of motorized bikes) so i'm thinking about going that route. The only advice i've gotten so far was to get a bike with cantelever brakes so i'll actually be able to stop from 30-40 mph safely.. Any other advice or knowledge would be appreciated. Oh and my names Tony btw if you haven't figured that out yet. Thanks all.

  2. Mountainman

    Mountainman Active Member


    HT dealer close by here sells MB's complect for 300 dollars
    PM me if interested

    what a deal -- 25 dollars for an install !!

    makes it good to ride that thing
  3. bluegoatwoods

    bluegoatwoods Well-Known Member

    However you do it, I'd avoid the ebay sellers. You just don't know who you're dealing with.
    And you can get just about the same price from trusted mbc vendors. Links on the left of these pages.

    You've got just about enough money to build yourself a bike with a two stroke, frame mount engine. There's some other stuff you'll want to add, but they can wait a little bit.

    So I'd go ahead and do it. I doubt if you'll regret it.
  4. will_start

    will_start Member

    My one piece of probably bad advice, use super-glue everywhere.
    For me, It prevents things falling off.
    these motors viabrate the bike lots,
    and in my humble expensive glue costs money,
    and runs out.

    Read the stickies in each area, they help lots.
  5. wheelbender6

    wheelbender6 Well-Known Member

    Buying an engine kit in your budget should be doable. I spent very little on my engine kit and it has been reliable enough for 50 mile round trip commutes to work a few times per week.
    Since you are in a hilly area, your rear sprocket should be at least 40 tooth. Good luck.
  6. Hawaii_Ed

    Hawaii_Ed Member

    Man, save the $25 and do it your self. These kits are not that hard, and the reward of building it yourself is worth it. Any obstacles you hit we can help ya overcome :) And worse case, if you just can not figure it out, then you can take it to your guy.
  7. duivendyk

    duivendyk Guest

    If you have hilly terrain,a single-speed setup is unlikely to cut it!.You need GEARS !.SBP has a kit you can use in conjunction with derailleur or geared hub.But without gears you're either geared too low for the flats or to high for the steeper hills.
  8. hurricane billy

    hurricane billy New Member

    how well or sould i say how easy are the kits to use with say a 3speed hub?
    i know have a beach c with 80cc 1sp . info on gears would be helpfull...
  9. duivendyk

    duivendyk Guest

    The SBP kit is intended for a bike with a front derailleur setup with a jackshaft driving the large chainwheel and the small driving the rear wheel sprockets.Shifting is done with the rear derailleur but could also be done with a multispeed internal hub(expensive ).You need a freewheel crank at the front,check out Sick Bike Parts.
  10. duivendyk

    duivendyk Guest

    TGS,I did some number crunching,to see if you might get away with a single speed drive or not,which would be cheaper of course.The answer is maybe,it would help if you got an 80cc HT engine,you need all the torque you can get (torque is pretty much proportional to displacement) so the bigger the better.I think they have a 4:1 reduction built in .With a 12/44 (12T ? output sprocket) reduction to the rear wheel you have an overall reduction of 14.67 which means a speed of 25mph at 5 k rpm and should be able to get up a 5-6? % grade.assuming that you + bike don't weigh more than 275 lbs.Use a 'clamshell' rear wheel sprocket mounting bracket instead of that through the spokes clamping abortion.
    Last edited by a moderator: Jun 25, 2009
  11. duivendyk

    duivendyk Guest

    HB,go to for more info,3 speed hubs usually have ratios of 0.75-1.0-1.33.I think sprockets can be ordered for them from 15T to 20T,
  12. hurricane billy

    hurricane billy New Member

    thanks for the info . duivendyk , Lynchburg ? i used to live in danville for a while. wish i knew of this bike thing back then.
  13. TonyGotSkilz

    TonyGotSkilz New Member

    Thanks for all the advice, i'm pretty mechanically inclined so i'm probably going to put it together myself, I'm having a ***** of a time finding a bike right now. Not cause i can't find one in my budget but because I can't get to any of the nicer one's i've found without a car (which i don't have). I have to ask about the kit i'm getting because i'm not sure how the sprocket setup would work. I would like it to be attached to the front sprocket so i could still use the rear gearing but I know i've seen one like that but i guess i'd need a "free wheeling" sprocket right? This is harder than i expected but i can't wait to have a finished bike these look like so much fun.
  14. TonyGotSkilz

    TonyGotSkilz New Member

    Oh and another question, i plan on getting a mountain bike because i want to be able to ride it without the motor on fairly easily. How much do these motors weight? I'm figuring about 15 lbs with fuel is that right?
  15. duivendyk

    duivendyk Guest

    That's in the ballpark,depends a bit on the configuration,frame mount prob. a bit lighter.The cheap Chinese engines are pretty much all f.m.With a mountain bike you have (potentially) decent brakes,they are IMPORTANT.If you can afford it get a clamshell rear sprocket mount, it will accurately and reliably mount your rear sprocket and can save you a lot of grief.The HT setup does not have a freewheel in the engine drive train,so you have to pull the clutch in order to use pedaling power (some resistance there).READ the stuff posted about getting new HT engines in adequate shape for actual use,can save you grief&aggravation!!.Good luck.
  16. Hawaii_Ed

    Hawaii_Ed Member

    I have ridden mine without power a few times (no gas gauge LOL), the weight was not my problem as much as just the chain drag and all. The shift kit bike is def better under pedal power, it has less drag than the bulky chain and spocket setup.
  17. Esteban

    Esteban Active Member

    Two things I would be concerned about. This is MY OPINION !
    1. Someone trying to sell me what they call an " 80cc " engine.
    2. Someone offering to install a kit for $25. Either he is a good friend, [ which is OK ] or he has never installed one before. If the latter is the case, it will be the last one he ever installs for $25.
  18. duivendyk

    duivendyk Guest

    That's his problem!,is there such a thing as an 80cc DISPLACEMENT engine or is it closer to a 70cc engine.There is no question that something like the SBP kit is far preferable over the single speed drive ,worth savingup money for.For example:
    1) Much easier on the engine,with hills to contend with there is an inevitable compromise,geared low you'll be tempted to be screaming along with the marginal HT engine at high rpm.The bearings are only so so,but geared too high ,you wont have enough oomph on steep hills.Runnning WOT not good for it either.
    2) Getting the rear sprocket mounted right &keeping it there is a real pain,the 'clamshell' mounting seems to work well ,but sets you back quite a few $$$
    3)The chain tensioner is a source of trouble,it is crappy and dangerous to boot ,and frequently needs to be replaced with something better,more $$$ .It is a LIABILITY if the engine seizes (which is not uncommon) because it's likely to end up in the spokes and you scraping along the pavement,which is where you certainly don't want to be.
    4)you have no real freewheel which app. is a real 'drag'
    The SBP kit costs more and is prob not ideal either,might be a b**ch to install with the multiple chains, but does not have the serious weaknesses I cited.Gears are very,very nice to have esp. if you don't have all that much power to start with and need not to overstress your HT engine.Take your pick.
    Last edited by a moderator: Jun 27, 2009
  19. 1. my rear sprocket went on like a piece of cake(9 bolts to tighten took a while).
    2. my engine and bike can drag 2 people behind it dragging them down the road(but i wouldnt do that but i could)
    3. i have a bolt and 2 hose clamps to hold my tensioner in place(its not going anywhere)
    4. when do i plan to peddal? well i dont,thats why i got a engine,i only peddal when i need to,but if you dont want no drag dont put a engine on your bike. bike goes 35mph with a 44t and it loves to go up hills,it actually rides better going up hills.
    6. my engine loves to run wide open and i think it will last longer than me.

    these engines weigh 20lbs plus fuel and i would charge atleast $100+ to do a simple bike, someone actually offered me $550 to do a bike for them,that includes a $99 bike and $149 engine.
    Last edited: Jun 27, 2009
  20. duivendyk

    duivendyk Guest

    1) Trouble reports about problems mounting rear sprockets abound,not too healthy for spokes either
    2) I would like to see a video of you dragging 2 people behind you.,you can't with an ordinary HT engine.Needless to say such silly statemens don't exactly enhance your credibility.It would take a few hundred pounds pull to do this.You may have 30 pounds or so and would never get going in the first place.Just ridiculous.
    3) If your engine seizes ,which they are prone to.your chaintensioner is not likely to survive,nor your rearwheel,or possibly you yourself a couple of hose clamps are not likely to hold the fort.These crummy chain tensioners are for the birds.
    4) I never said it could not get up hills,I stated hills steeper than 6% would be a problem,if the combined weight was over 275 lb
    5) Your engine may 'love' running wide open,unfortunately how long it will last has little to do with this,I hope for your sake you outlast it,and maybe manage survive to the ripe age of 35.Good luck.
    Last edited by a moderator: Jun 28, 2009