building a motorized bike, looking for information

Discussion in 'Introduce Yourself' started by XkronusX, Sep 8, 2011.

  1. XkronusX

    XkronusX New Member

    hi all im new to building motorized bikes and im looking for any important info you have to offer.

    what i have already is a 21 speed bike, im looking to make it a chain drive using a sprocket on the left side of the back tire to drive the wheel directly without stopping the possible use of peddling in case anything happens.

    what im looking to find out is what type of chainsaw/chainsaw motor i should look at getting, i was thinking weed wacker at first but i have heard that they dont have a clutch so its more difficult and not the way to go with a build.

    also im looking at info on gear ratio, my rides are going to be mainly in town, flat land one possible uphill, which i can bike through so not a big incline. but i heard its dangerous doing inclines with certain gear ratios.

    im also looking at the best possible breaking system, possibly disk breaks or some other type of system.

    so my questions in bullet points for easy reading are

    - best chainsaw motor to use
    - reasons for clutch
    - best gear ratio, how to achive good gear ratio
    - dangers of inclines
    - how to govern if nessecary
    - kill switch how to
    - best breaks to use

    Thanks in advance for any help :D

  2. 2strokepoke

    2strokepoke Member

    can't help you with a motor or ratios but i can tell you its nice to have a clutch so you can run the motor while the bike isnt moving.

    what brakes is your bike already equipped with?
    do you have a budget?
  3. ddesens

    ddesens Member

    Just buy a kit. It will come with most everything you need. Ebay or one of the sponsors here.
  4. XkronusX

    XkronusX New Member

  5. PatrickW

    PatrickW Staff Member

    Kronus...Welcome to MBc. I looks like you have done your homework for someone who has not done this before. Just make sure that the Engine will fit in the 'V' of the frame nicely. Get all of the measurements and make sure it will fit properly. Read all of the 'Sticky' notes at the top of this and other forums...they contain valuable information on your first build, and rules you need to follow on the forum. It looks like you picked a reasonable 2-stroke motor, and a bike that should do well around town in general.

    There are some preparatory points you are going to want to follow, tho...such as re-grease all of the bearings with a good lube, and throw away the original Chinese mounting bolts and use U.S. Grade 8 (or what is comparable in Canada) instead. Those kits come with the cheapest nuts and bolts available, and replacing them only costs a few bucks...that will save you a lot of trouble down the road. Read all you can in our 2-stroke forum, and use our search function to find out what a 'Torque-Stop' is, or ask one of our 2-stroke gurus about it. It is just a bent piece of metal that keeps the engine from twisting when you open the throttle quickly. If you are at all familiar with drag racing, we run a chain from the left, front corner of the engine block to the left front frame keeps the engine from 'lopping-over' and twisting itself out of the motor mounts...same idea, only on a different scale. Anyway, it sounds like you are good to go, and have made some good choices. Just make sure you check your measurements twice before you lay out your hard earned cash. Btw, you do realize that you do not really have 21-usable gears? Actually, you have gear 1 on the left side with 1-5 on the right side; gear 2 on the left side, with 4-7 on the right side; and gear 3 on the left side for 5-7 on the right side. That gives you about 12, safely. Actually, other combinations get the gear-to-chain allignment out of whack. Actually, I try and keep mine close to 2 on the left gear, and 4,5,6, on the right gear. That gets me where I want pedaling, and the rest of the time I kick in the motor. Good luck to you, and God Bless.

    Last edited: Sep 16, 2011