Centrifugal clutch questions

Discussion in 'Friction Drive' started by seabillco, Jul 29, 2008.

  1. seabillco

    seabillco Member

    7-29-08
    Hi, all
    I've built two friction drive bikes but neither uses a centrifugal clutch.
    I'd really like to build one with a centrifugal clutch so it would idle but I have two questions I'm wondering if anyone can help me with:

    1) What is a good way to attach the drive spindle to the bell housing?

    2) Are these little clutches from weed eater type engines strong enough to actually work?

    Thanks for any thoughts!

    Steve G.
    Grants Pass, Oregon
     

  2. Nuttsy

    Nuttsy Member

    If the system you use now for fastening the drive roller to the output shaft is a threaded configuration, just stay with that and find a clutch bell with the appropriate threads. I believe you were using BMX pegs??? Threaded hole? If that's so, you would just run a bolt through the peg and into the threaded clutch bell.
    Check out some of the online scooter and go kart parts sites for the various clutch configs. And, yes they work!
    WC
     
  3. seabillco

    seabillco Member

    Hi, Nuttsy
    Thanks for your help!
    The clutch bells I have for the Ryobi engines are not threaded. They have a square hole that accepts a long, flexible, square shaft for driving something at the end of the shaft.
    So, you're suggesting there are web sites that sell clutch parts that will thread onto my crank and also accept a bolt...
    That is definitely what I need. If you have any web sites in mind, please let me know.
    I wasn't aware such a thing existed so I'll start looking right now.

    Thanks again!
    Steve G
    Grants Pass, Oregon
     
  4. Happy Valley

    Happy Valley Active Member

    Steve, did you find what you are looking for?

    I think just about all the friction drive setups I've seen use just what Nuttsy described and are plenty strong. What size engines are you planning to use?
     
  5. seabillco

    seabillco Member

    Hi, HV
    Thanks.
    No, sadly, I'm not finding anything even close to what I want based on what Nuttsy suggested.
    I'm using the Ryobi 2 and 4 cycle engines. They have a 3/8" crank that the clutch threads onto with a 24T thread.
    I've been removing the clutch and replacing it with a BMX foot peg with the same 3/8 - 24 threads. That's been super easy and it works.
    I'd like to leave the clutch on and SOMEHOW attach the BMX peg directly to the bell so it will spin only when the clutch is engaged due to high RPM.
    I could weld the BMX peg to the bell housing but that presents several problems relating to centering the peg and the thin metal on the housing vs. the very hard and thick peg metal. The temperature required to penetrate the BMX peg would obliterate the thin, bell housing.
    So, I was hoping to find a clutch with a 3/8-24 bore and a bell that is threaded, as Nuttsy says, to attach the clutch to the crank and then then the BMX peg to the bell.
    I've looked at several go cart web sites and I'm not finding any clutches with a threaded bell. Also, by far, most clutches are for larger bores and have a sprocket on them for a chain drive.
    If you have any ideas, I'd appreciate it.

    Thanks!
    Steve G.
    Grants Pass, Oregon
     
  6. Happy Valley

    Happy Valley Active Member

    Couple of things:

    Two post up you mentioned "clutch parts that will thread onto my crank"
    Not sure what you mean by this but the drum doesn't thead on the crankshaft.

    The other thing is I personally wouldn't ever think about welding onto a drum unless you had a real mongrel parts fit.

    How aabout this:
    http://www.staton-inc.com/Details.asp?ProductID=2613
     
  7. seabillco

    seabillco Member

    Hi, again
    One more idea I had to attach a spindle to the bell housing was to first attach the spindle to a plate and then attach the plate to the bell housing with small bolts. I'd have trouble keeping the bolt heads from hitting the clutch, though.
    Again, the bell housing is very thin metal compared to the BMX peg.
    I might be able to step it down by welding the peg to a plate that is only a bit heavier than the bell housing and then welding the plate to the housing.
    I was hoping someone smarter than I am had already addressed this issue...

    Thanks again!
    Steve G.
    Grants Pass, Oregon
     
  8. I have a method of attaching to the clutch bell with square stock I found at both True Value and Menards. Check out my ride with a Ryobi with the stock clutch, it works so far if it stops working I will put it and go with a dirrect drive.

    Hang on, I will post detailed photos later when I get home.

     
  9. seabillco

    seabillco Member

    Hi, again, HV
    The bell housing thread into the crank END. It is just a small 10-24 bolt to keep the housing from coming off.
    The clutch itself threads onto the crank.
    I think we're on the same page with welding onto the drum. It doesn't seem like a good idea to me given everything.
    Hence, the problem...

    Thanks again!
    Steve G.
    Grants Pass, Oregon
     
  10. seabillco

    seabillco Member

    Hi, SVH
    Thanks! I'd sure like to see that method when you have time.
    I'm really scratching my head here...

    Thanks again!
    Steve G
    Grants Pass, Oregon
     
  11. Happy Valley

    Happy Valley Active Member

    Heh, just read through your other recent clutch thread Steve, hadn't seen it before. I see you've probably been all over this issue every which way you can already. If I come up with anything I 'll post it. Good luck.
     
  12. seabillco

    seabillco Member

    Hi, HV
    I think maybe you solved it with your link to Staton, but I'm not positive.
    I see they have a Clutch "Drum 2 - 1/8 with 3/8-24 threads" at:

    http://www.staton-inc.com/Details.asp?ProductID=2607

    And, I see they have a Clutch rotor 2 - 1/8 inch or 54mm at:

    http://www.staton-inc.com/Details.asp?ProductID=2645

    If I'm getting this, the clutch rotor is actually what I would call the clutch and it appears it would thread onto my crank since it's a 3/8" - 24T.
    Then, what they call a clutch 'drum' is what I'm calling a clutch housing. I'm unclear how the housing would attach to the crank (or whatever) so it wouldn't fall off.
    Once you get the housing on, then it appears the BMX peg would thread into the housing just like Nuttsy said.
    Can anyone see what I'm missing here? What holds the 'drum' on?

    Thanks a lot for all the help!
    Steve G
    Grants Pass, Oregon
     
  13. Happy Valley

    Happy Valley Active Member

    Steve
    Hats off to your inventive MB builds I see on your blog!

    I'm gonna post a link, maybe you've seen it or maybe not, and I know it doesn't pertain exactly to what you are seeking for your DIY drive set-up.
    I do so hoping it might offer an insight into your solution.

    http://www.youtube.com/watch?v=GCDOoWD4NGc&feature=related
     
  14. seabillco

    seabillco Member

    HV
    Thanks for the kind words.
    Yes, I've watched that video several times.
    I'll watch it again and see if I can pick up something new.
    sweetvalleyhigh says he has solved the issue I'm worried about and will post pictures later when he gets home.
    If I get a solution, I'll be sure to explain it here in case anyone else is struggling with this issue.
    It's been a lot of fun!

    Thanks!
    Steve G
    Grants Pass, Oregon
     
  15. seabillco

    seabillco Member

    Hi, HV
    I watched the video again and have looked at SVH's great-looking project and I think I see my problem.
    The system on the YouTube video has a U member, bearing and collar that stop the clutch housing from coming off. SVH's ride, similarly, has a plate on the outside that the spindle butts into with a bearing in the end that, among other things, holds the clutch housing in place.
    I may need to modify my build to this idea in order to use a clutch.
    I really like SVH's design.
    Thanks again for reading and helping!

    Have a great day!
    Steve G.
    Grants Pass, Oregon
     
  16. Nuttsy

    Nuttsy Member

    Seabillco,
    I think what you are missing is the idea that the motor, shaft, and clutch(rotor) are one part of the system. The clutch drum(bell), and drive roller are independent of the motor. You can mount the drive roller to the clutch drum by a simple nut and bolt through the drum and into the peg(roller). The sticking point would be how that setup is supported and perfectly centered over the clutch. I am not familiar with your support bracket system but the drive roller would need to be supported on both ends with bearings and collars. These offer the needed support and centering.
    I also don't know the existing clutch bell setup, but it may be possible to drill out the square hole drum and run the bolt/shaft setup through that. Or find a carriage bolt that fits that square hole. Then all you need to buy is the local hardware store stuff.
    I know, clear as mud!
    There is a YouTube video of a guy that made a friction drive and shows at length all the parts and how they go together. Its a 3 parter. Search YouTube for it with terms like "friction drive"; "motor bike". If I can find it I'll send the link along.
    WC
    Never mind. That was the link above and you claim to have seen it already. Sorry.
     
    Last edited: Jul 29, 2008
  17. seabillco

    seabillco Member

    Hi, Nuttsy
    Thanks!
    Yes, I think you're right. I think my problem is that I didn't see it all as one system.
    I think I get it now.
    I may need to revise my design...

    Thanks again for your patience!
    Steve G
    Grants Pass, Oregon
     
  18. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    http://bikemotorparts.com/page05.html

    there are all the parts for a friction drive system
    looks to be about the same design as Staton

    That is for 76 / 78 mm clutch shoes on your motor

    Are you sure your engine use the smaller 54 mm clutch?
     
  19. seabillco

    seabillco Member

    Hi,
    Thanks for the link. That seems like a very good kit, especially for the price.
    I don't think my engines' stock clutches are compatible. They are all Ryobi engines with a 3/8" 24T threaded shaft.
    The stock clutch measures 60mm in diameter. The stock bell housing is 61.5mm diameter. I might be able to get a proper clutch with my thread pattern.
    I'm guessing it would be wise to buy one of the recommended engines if you get the kit.
    Again, it looks like a very nice kit for the price but I don't know how much the engines would cost.
    For me, I'm a DIY kind of guy and just trying to figure a way to connect the stock clutch to the spindle.

    Thanks!
    Steve G
    Grants Pass, Oregon
     
  20. mark2yahu

    mark2yahu Member

    parts

    Seabillco, you can get a clutch bell and a freewheeling drive roller from www.bikemotorparts.com and other parts separately. :cool:
     
Loading...