Ryobi 31cc clutch removal

Discussion in 'Friction Drive' started by seabillco, Jul 15, 2008.

  1. seabillco

    seabillco Member

    7-15-08
    Hi,
    I just removed the clutch housing and clutch mechanism from my 2nd Ryobi 31cc weed wacker engine and wanted to pass on this tip in case it will help someone.
    If you are having trouble removing the clutch housing, there's a size 20 Torx bolt in the end of the crank shaft holding the housing on. You can't really see it because it's deep inside the square shaft that protrudes from the clutch housing.
    I put some 'Break Free' oil in that opening and left it overnight. The next morning, I took out the spark plug and crammed some cotton rope into the spark plug hole (using a pencil's eraser end) to fill up the combustion chamber. Leave some rope hanging out.
    This will keep the piston from moving and will allow you to turn the bolt to remove the clutch housing. This way, you won't break any fins on the flywheel by inserting a screwdriver in them.
    With that done, turn the Torx bolt in the square shaft on the clutch housing CCW, as normal; it's NOT a left-hand thread. With the Break Free oil working overnight, it just popped right off and I was easily able to remove the clutch housing.
    This exposes the clutch mechanism. With the rope still in the combustion chamber, use pipe pliers on the largest opening and grab the clutch mechanism on the metal ears - NOT the springs - and turn the clutch mechanism CCW, as normal to loosen things. Again, it just spun right off without any problems or much effort.
    It was so easy to remove the housing and clutch, I thought I had broken them!
    When you're all done doing whatever it is you're doing, simply pull the rope out. Any little cotton pieces will burn up.
    Also, FWIW, I understand you must clean the spark arrestor (if you've got one) every 25 hours. This could prevent your engine from running due to excessive back pressure.
    Finally, FWIW, I have found that the flywheel keys shear pretty easily on these small, 2 stroke engines. If your engine isn't starting and you can't figure out why, check that the flywheel key is intact and in the right place.
    I hope this helps someone.

    Steve G
    Grants Pass, Oregon
     

  2. WOW, this helps a lot I was wondering how to remove the cutch just last night. I found the torx screw but could not find a way to keep everything from moving around while loosening it. Thanks for the other info as well, I will check my engines for these things too.

    I would love to see a photo of this bike when completed.
     
  3. seabillco

    seabillco Member

    Photo of MB with Ryobi 31cc engine

    7-15-08
    Hi,
    You're welcome!
    I've posted pictures and video of how I built my 1st MB on my personal blog at:

    http://steverg.blogspot.com/

    It might help you.
    Also, here's some pictures for you right now.

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

    Attached Files:

  4. Nice clean and simple.

    Watch that lever in front of the seat it looks menacing!
     
  5. seabillco

    seabillco Member

    7-15-08
    Hi, SVH
    The suicide clutch lever has not been a problem so far, but I don't like it either.
    I'm working on a motorcycle style clutch lever to replace it.
    On my 2nd project, I would like to weld the drive spindle to the clutch housing so I'll have the centrifugal clutch operating and, hopefully, I won't need the manual clutch.
    That presents some issues I'm still working on...

    Have fun!
    Steve G
    Grants Pass, Oregon
     
  6. brendonv

    brendonv Member

    Cant u just use a flat head screw driver to get the screw out? I gotta take mine off as when the engine idles it engages and disengages, is this normal? I think i have to replace the spring, could you possibly get pics of step by step instructions to getting it off? Also i dont really like the idea of filling my cylinder with rope, cant i just shove a screw driver in the fan? Thanks.
     
  7. BSA

    BSA Guest

    This is a clutch thread and it's for a rack mount so it belongs in rack mount drivetrain. Moved

    BSA
     
    Last edited by a moderator: Jul 15, 2008
  8. seabillco

    seabillco Member

    centrifugal clutch removal

    Hi Brendonv

    Brendon
    I tried to remove the clutch without using the proper tools and I ruined the crankshaft's threaded end. So, FWIW, IMHO, etc, I would not try doing it with a screwdriver. I'd use the proper Torx driver.
    I, too, was a little concerned about putting cotton rope in the engine but I realized I was putting far too much stress on the aluminum flywheel fins and I was willing to try something else rather than pay $35 for a new flywheel. Also, I had heard of this trick decades ago when I was a kid.
    Having done it both ways, I can tell you, without a doubt, the rope trick is much better ESPECIALLY if you use the oil to loosen the threads up.

    Good luck!
    Steve G
    Grants Pass, Oregon
     
    Last edited by a moderator: Jul 15, 2008
  9. brendonv

    brendonv Member

    So did your clutch sort of disengage and engage at idle? It doesnt fully engage it sorta makes a grinding noise and quickly engages than disengages. I dont want to take it off if i can help it, also my clutch drum is sorta loose, i mean the screw it tight and isnt going anywhere but theres about 2mm of slack on the drum i can move it up and down. Is this normal? Is this what might be creating the problem? Im also thinking either the spring has had had it or theres some grit in it or something although that wouldnt explain the skipping, just the grinding sorta noise. When i pull the pull start hard with the engine on off the clutch sorta makes a grinding noise and the end of the pull.
     
  10. seabillco

    seabillco Member

    clutch is probably ok

    7-15-08
    Hi, again, BrendonV
    I have 2 of these engines and they both act the way you're describing.
    They work fine.
    I'm thinking you should probably just leave the clutch alone unless it doesn't work.
    My clutches both kind of half work and half don't when the engine is idling. With the resistance from the wheel (once it's mounted on the bike), they will do what you want.
    Once the speed builds up enough, of course, the 'dogs' will bite the housing and it should work fine.
    I'm wondering if you have any ideas how to attach your drive spindle to the clutch housing?
    I'd sure like some help on that topic.
    :grin:

    Thanks!
    Steve G
    Grants Pass, Oregon
     
  11. brendonv

    brendonv Member

    I actually already have a friction drive bike which i made with a ryobi 30cc grass scorpion whipper snipper ( no clutch ). I got this new motor 31cc Weed wasp at the tip for 5 bucks and spent about 20 on it to get new everything rubber as it was cracked and a new spark plug and many hours of cleaning, tuning the carby and cleaning the muffler. My friction drive is made of 30mm diameter knurled alu which ive covered in a JB Weld and sand mixture as the knurling wore off.

    My new motor is going to be chain drive so im going to weld a 10T Sprocket to the clutch shaft ( it fits snug on ) and then going to go to a 50T sprocket mounted on a bike pedal hub thing and on the other side have another 10T sprocket then to another 50T on the wheel. These sprocket T are estimates, ruffly around those numbers, what ever i can find basically. The 10T sprockets i can get from the back gear changer on a mountain bike, it has 2 10T sprocket in there. The two 50T i can get from a bike shop or ebay. I may get one 50T or 60T on the hub and get a 44T HT sprocket from ebay for the wheel.

    So the gearing is ruffly 10,60,10,44. That will give me some nice hill climbs and give me speeds of around 45-50km on the flats.
     
  12. seabillco

    seabillco Member

    7-15-08
    BrendonV
    That sounds very nice. I'd love to see a picture when you get far enough.
    I'm VERY pleased with the performance of my Ryobi 31cc 2 stroke engine on a friction drive I built. I pivot the entire engine frame up and down as a clutch.
    I saw your video, I believe, on Youtube and it was your video that inspired me to build my MB since I, too, have a Ryobi 31cc engine.
    At the moment, I'm working on motorizing my recumbent. It should be a lot of fun.
    I have details and video of my project at:

    http://steverg.blogspot.com/

    if you're interested.

    Thanks!
    Good luck!
    Steve G
    Grants Pass, Oregon
     

    Attached Files:

  13. brendonv

    brendonv Member

    one step ahead of ya, ive already read the whole thing, i got the link at your build thread. Oww u made urs because of my vid? Wow cool. XD
     
  14. seabillco

    seabillco Member

    BrendonV Video on YouTube

    7-15-08
    Hi, again, BrendonV
    Yes, I saw your MB on YouTube and realized that you had the same engine that I had sitting in my garage.
    I ordered a frame mount MB kit online but it never arrived so I decided to build my own using your bike as a starting point.
    I was amazed at how fast you were going in one of your videos. So, I started working on my MB project because your video convinced me it would work.
    I saw a thread here that gave me the idea to pivot the engine off the wheel for a 'clutch' and that solved the main problem I was having with the design.
    So, THANKS to you and to YouTube!

    :smile:

    Have a great day!
    Steve G.
    Grants Pass, Oregon
     
  15. brendonv

    brendonv Member

    hehe np, yeh i was going to make it pivot but couldnt be bothered lol, now im making a clutch chain drive so i might sell my friction, see how we go.
     
  16. mbatl

    mbatl Guest

    how did you mount to engine to the wood seabillco? I've got the same motor and gave up on trying to mount it, but I might cancel my HT order and try it.
     
  17. seabillco

    seabillco Member

    Engine mount to plywood

    7-15-08
    Hi, mbatl
    I drilled holes in the plywood and bolted the engine to the plywood.
    You have to cut a hole in the plywood that's big enough to let the spindle and, in my case, the flywheel pass through.
    With the hole, you need to leave as much wood as possible to capture the ears on the engine casing so you can run bolts through them.
    I've attached a picture where I drew white circles around the bolt heads from the spindle side to help. But, it's hard to see.
    I hope this helps.

    Steve G.
    Grants Pass, Oregon
     

    Attached Files:

  18. mbatl

    mbatl Guest

    Thanks, I wish was looking at mine right now, but I'm guessing that there are probably four mounting bolts that were already in the engine block, correct? So you basically got some longer bolts than what the motor came with so it would reach the wood and mount securely?
     
  19. Seabillco,

    Do you feel that the way the drive roller contacts the tire causes excessive stress on the engine? How long have you run with it in this configuration? I think this would be easier than using bearings on both ends of the roller to reduce stress on the engine.

    Like I may have mentioned before I have the same engine, and if this works well I think I will follow your lead.
     
  20. seabillco

    seabillco Member

    motor mount / spindle support

    7-15-08
    I hope I'm doing this response correctly by answering two questions at once. If there's a better way, someone please let me know.

    mbatl: Right. Find longer bolts and go through the plywood and then through the engine block 'ears' where the old bolts were located and put a nut on the other side with some washers to spread the load and lock washers, too. It works fine for me.

    svh:
    I have about 150 miles on this set up. I am aware that people say you need to support the other end of the spindle and I just didn't have the materials and parts (U frame and bearings) to build it that way.
    So far, I have had no trouble but it's not been very long. I picked up 3 more of these engines on eBay for $25 each so, frankly, I'm not too worried if one fails due to the side load on the crank.
    By the time I burn up the 3 engines I have, I'll probably have acquired the materials and parts to build a better mouse trap.
    I just built this for fun. It cost me $5 for the BMX foot peg. The rest was just scraps I had around the house. If I was trying to commute to work or something, I'd just use my motorcycle.

    :grin:

    Steve G
    Grants Pass, Oregon
     
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