front engine front wheel drive question

Discussion in 'Rack Mounted Engines' started by rkbonds, Sep 16, 2008.

  1. rkbonds

    rkbonds Member

    Ok I'm still the new guy here but, quite the shade tree engineer. I've got a 25cc weedeater motor w/clutch that I'm working on putting on the front of my mtn bike. I'm pretty sure I've got the drive system worked out (chain drive) but, I was wondering if anyone had any ideas for mounting the engine? I'm playing with a few ideas in my head just didn't know if someone else had already tried this before or not. I know it would be easier to put it on the rear but I don't have the room to mount it in back. And yes I have since modified the trailer to pull level.
    Last edited by a moderator: Nov 25, 2008

  2. s_beaudry

    s_beaudry Member

    First, I hold NO engineering degree myself....

    Before you mount the 25cc engine, that picture is showing you, 3 kids, and a pull trailer as well. This is alot of weight and momentum to get going, so you are looking at a fair amount of pedaling before getting any power out of the engine. 25cc's may be a little small for what you are using it for. But, if you get up to speed, it would/could have enough torque to keep you going at a reasonable speed.

    Next, the engine mount, this may be a little more difficult as the wheel pivots and would cause a issue for mounting.

    Take a close look at the following link, it is a GEBE setup, but it will show you how to mount the engine ro the axle and forks....

    Any questions, please ask us at the forums here, we are very friendly!
  3. rkbonds

    rkbonds Member

    I will only be using the engine to pull me by myself and not with the trailer. I do plan on doing most of the pedaling but would like to be able to use the motor for short commutes (lunch, store,etc...). Thanks for the link. I can't decide what would be the quickest drive system to get going quicker. I plan on the final product being the chain drive but, think friction would be quicker to get going until I get all the parts for the chain drive. It would also give me the chance to work out any bugs in the system without ruining my wheel. I don't have an engineering degree either just a lot of determination I guess is what I should have said. lol
  4. Mountainman

    Mountainman Active Member

    looks like that should turn out to be -- A LOT OF FUN !!!

    a friction drive to hold you over -- I sure like mine

    is that the Huntsville close to Tuscaloosa ?

    we were out there a year ago -- many nice roads for riding..

    Ride That Thing - Mountainman
  5. rkbonds

    rkbonds Member

    Tuscaloosa is a several hours away but, same state. I'm looking forward to getting it finished and get to riding.
  6. s_beaudry

    s_beaudry Member

    With you yourself riding the bike for those short trips, that engine should work very well for you...

    Start with the friction and when all the bugs are worked out, switch over to chain or belt....

    But, you may just find you like the friction fine and stay with it, if so, invest that money in a new engine, a Honda GX50 has plenty of torque to handle you and the kids!

    Stay safe and keep the kiddies happy!
  7. Soon I'll have a Titan mount up front for my trike.
    I have plans for mounting and it does not involve drilling into the fork.
    I have to see first if it will work I'm rather sure it will but it would involve rather inexpensive hardware at lowes and my gooseneck.
    I'll get back when I have it all figured out.
  8. rkbonds

    rkbonds Member

    Today I got my short drive shaft made and got it and the clutch assembley put together today working properly. I hope to get the motor mounts fabbed up over the next few days. I'll keep you posted on the progress as it comes. I'm wondering if it will still be considered a motored bike by the state of Alabama if I'm not using the motor???
  9. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    25 cc weedwacker
    Are you using a gearbox?

    Or driving the front wheel directly with a sprocket and chain?
  10. rkbonds

    rkbonds Member

    Right now the motor is set up with a drive wheel. I don't plan on using a gearbox or a jackshaft all of the ideas I'm working on drive directly from the motor to either friction, chain, or belt drive. The weedeater engine came with a clutch ( most of the better models do) which will all me to set it up this way.
  11. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Friction will work on any size wheel with no gearing problems

    Have you calculated your gearing for chain or belt drive?

    GEBE belt drive works driving directly from a motor like yours
    because the drive ring is about 17" in diameter and the clutch
    sprocket is very small

    What size chain sprockets do you plan on using?
  12. HoughMade

    HoughMade Guest

    I don't think you are going to get this to work with chain drive without gear reduction. I'm thinking that friction is the order of the day for you.
  13. rkbonds

    rkbonds Member

    I haven't calculated the ratio's with the chain drive. I figured I'd use trial and error I have 3 different sizes for the drive gear and 8 or 9 for the wheel and they shouldn't be too time consuming to change out ( I hope ). Now if I end up doing the belt drive I only have one size ring for the wheel and I don't have a drive pulley yet so..... unsure on that right now. I also have 2 different size drive rollers for the friction drive. I figure I'll use the friction drive to find out where I think I need to be as far a gearing. Especially considering I only plan on using the motor for cruising take off's and up hill's will be all pedal power. I'm not so much concerned about top speed or low end grunt just a good midrange is what I'm looking for.

    HoughMade I take that as a challenge ;) I enjoy that.... tells me I'm gonna have to work extra hard to make the chain drive work. All in good fun we'll have to see how everything works out in the end project.

    What I'm having the biggest issue with right now is the mounting. Can't figure out the best way to set it up. :(
  14. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    what size wheel ring do you have for belt drive?

    What kind of belt are you going to use?
  15. rkbonds

    rkbonds Member

    It's a 20" ring not sure on belt's haven't gotten that far yet. I was thinking about either an automotive type v belt or a lawnmower industrial type to start with.

    Opps I just realized I didn't say what size bike I'm using.... it's a 26".
    Last edited: Sep 19, 2008
  16. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Its like pulling teeth with you.....:p 64 questions
    you have a camera, take some pics of the parts

    Is it a whizzer sheave? you can use a 1/2" / 4L belt V belt
    how does it attach to the wheel?

    If so that will work gearing wise for the belt drive and has
    been done before

    This is a GEBE front wheel drive

    however unless you have sprockets for the chain drive
    that are very large it isn't going to work gearing wise

    trial and error???
    Easier to calculate it first.....
    Last edited: Sep 19, 2008
  17. rkbonds

    rkbonds Member

    What's a whizzer sheave? I'm doing all my stuff on the cheap. So far I have $00000 invested in my project. So all of the details haven't been worked out yet. All of the sprockets I have I pulled from other bikes and the drive gear I got off a pocketbike. The ring, I found not sure what it came off of or exactly how it will attach yet. So I'm up for any ideas you have to share on what you think might work better I'll try and get a pic of the engine as I have it set up now ( not mounted ) and post them soon.
    Last edited: Sep 19, 2008
  18. rkbonds

    rkbonds Member

    Here are some pics I managed to take today. I did manage to get the motor half way mounted today. I got the uprights fabbed up and mounted, still have to fab up a side to side mount, front to back, and a tensioner. Seems to be good so far. Hope to get it finished up tomorrow and take it for a test ride.

    Attached Files:

  19. s_beaudry

    s_beaudry Member

    Very nice work you have so far....
  20. rkbonds

    rkbonds Member

    I did some more work today and was able to take it for a ride :cool:. I've got to go get an actual adjustable tensioner tomorrow. I used a ratchet strap today for the test not the best idea I know but, it worked. I was bogging down pretty bad never reached high rpm's, not sure if that's related to tension or drive wheel size but, will have a better idea after I install the tensioner. I will say that other than that little problem I was very pleased with the ride and power. I'll post more pics after mounting the tensioner. :D:D