Ryobi 31cc clutch removal

[brendonv]

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.

 

[seabillco]

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

 

[brendonv]

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

 

[seabillco]

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!



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

 

[brendonv]

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.

 

[mbatl]

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.

 

[seabillco]

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

 

[mbatl]

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?

 

[sweet valley high]

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.

 

[seabillco]

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.



Steve G
Grants Pass, Oregon