Another Friction Drive, Last One I Swear!!

GoldenMotor.com
silverbear

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
Don't know how I missed this one. While I don't see myself building one of these (too many projects as it is), I really like the scissors engagement of roller to wheel. Perfect, simple, foolproof. My hat (if I wore one) goes off to Deacon and whoever/whatever inspired him to do this. And as usual, your execution of an already good idea is A+. A predator engine on sale is about a hundred bucks. They are easy to start and mine have run forever. Friction drive has a lot going for it for all the things it avoids... and for all the money it saves. This really is so much better than a china girl engine and setup and for less money. Someone could very well set up a small business making up a kit modeled on this design so that it is bolt on and ready for a Predator engine. I'd like to see it available as an alternative to the China girl. Well done, sir!
SB
 
cannonball2

cannonball2

Well-Known Member
Oct 28, 2010
3,682
221
63
Colonial Coast USA.
Thanks guys! That was the second full suspension bike I built. I still have the first. That's an easy way to mount a larger engine. Its was totally fabbed. Its a pretty quick build. The engine is not as awkward as it looks in the high position. I have nearly 8k on the original bike it is the work horse this one was a more sporty ride. Though I have built many different drive types, belt, chains, etc., this combination made FDs a favorite with me.
 
TheSignGuy

TheSignGuy

Member
Nov 24, 2014
459
9
18
seattle, wa
silverbear said:
Don't know how I missed this one. While I don't see myself building one of these (too many projects as it is), I really like the scissors engagement of roller to wheel. Perfect, simple, foolproof. My hat (if I wore one) goes off to Deacon and whoever/whatever inspired him to do this. And as usual, your execution of an already good idea is A+. A predator engine on sale is about a hundred bucks. They are easy to start and mine have run forever. Friction drive has a lot going for it for all the things it avoids... and for all the money it saves. This really is so much better than a china girl engine and setup and for less money. Someone could very well set up a small business making up a kit modeled on this design so that it is bolt on and ready for a Predator engine. I'd like to see it available as an alternative to the China girl. Well done, sir!
SB
Click to expand...
I cannot lose interest rather car truck motorcycle or bicycle, mechanics I love and if I had a welder I would crush the China girls so called income. Did you know in the winter kit prices spike as well for summer? Gas is 270 here that's pan handle change from my end perspective. If I shall ever run out of gas there is no way someone would be like oh no all I have is card. It holds less then a cup of coffee of gas and is cheaper then 3 items at the dollar store. So yea I am going to never loose interest.I am kinda in the process of selling these if I take up welding I'll be a shoe in on wa state prices most cl builders want 360 to 500 for a chunky build I will cut them in half on the price as long as I make 150 pocket cash I don't care for how long it takes to install.sll side business from my job. Btw I got that schematic drawn out on Christmas cardboard lol from the Christmas tree box.cvlt1
 
silverbear

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
As a newby consumer (if I were in the market for one) what I would want would be a bolt on kit so that I could provide my own bicycle, my own 4 stroke engine of around a hundred CCs (perhaps purchased at a local Harbor Freight) and my own throttle. A resource for the roller would be nice as an option. Keep the kit minimal, cut down on shipping costs. I would want to do my own build and not purchase someone else's choice of crappy new bike. Have the kit be strictly hardware and designed to fit multiple frames. Or, if need be multiple kits to choose the right one for a certain frame type. Make the kit well and of quality materials so that it is bombproof. There would be a market.

Back in the days when I was playing with friction drive Bikebugs, I made my own rollers out of epoxy or a used skateboard wheel. With some of the cast epoxy ones I mixed in fine sand to give more grab for wet conditions. Oak rollers sounds like a good choice and could be turned in different diameters as CB2 has done. They would be a good option to go with the kit. Just thinking out loud. This setup would make a good commuter rig with not a whole lot to go wrong with it. Reliability and vibration were my gripes with China girl kits.
SB
 
Last edited:
cannonball2

cannonball2

Well-Known Member
Oct 28, 2010
3,682
221
63
Colonial Coast USA.
The two Lifan FDs were built around full suspension bikes. The absolute best ride for a daily commuter or a long distance bike. The engine is mounted to the rear suspension and rides with the wheel. This allows the stock suspension to remain unchanged spring rate wise since the engine is unsprung. A kit would be easy to make, but the myriads of frame designs would have to be considered. This would also be easy to fab for the beach cruiser style that is so common. I built an FD using a Schwinn Point Beach and a 79cc HF engine. It differed in that it had a belt drive roller with a cent clutch. VERY easy to ride, but much more complex. A complex FD sorta defeats the purpose. The old Mongoose battle ax is the most used bike I have ever owned. I tailored it to be a traveling machine.
I will dig it out of the back of the garage and post some pics. Its a fully evolved practical FD that would easily take one coast to coast.
 
cannonball2

cannonball2

Well-Known Member
Oct 28, 2010
3,682
221
63
Colonial Coast USA.
Heres some pics of the Mongoose. Its totally purpose built. If it has any beauty its in functionality. It carried 5quarts of fuel in the bar mounted tank, and another gallon in the Blitz can. I have traveled many long distance trips in rural Ga. and it was nice to be well fueled. The Lifan on this bike is still governed. I used a locking thumb throttle. The governor acted as cruise control. I would set it and forget it for hours. This bike will climb any hill I have encountered with no problem. It is also set up to pull a single wheel trailer which it has on many occasions. The pic of the handle bars shows the controls. An M/C clutch handle works the lift clutch. Its drilled so a pin can be inserted in the up position for starting, and pedaling. I made a roller fender as I found out the hard way that riding in the rain you get badly sprayed by the roller.
My camera is checking out so I apologize for the pics. I tried to show the engine mounting but the pics are pretty bad. I carried tools and different size rollers for different riding conditions. They can be changed in less than a minute. The tach shows 77 hrs, and it has not been installed the whole time.
The Speedo gave up in the mid 6k mi range, and I guestimate there is an additional 2k on the rig. I have had many a great mile in this bike. This one stays with me til the end.
 

Attachments

silverbear

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
Yes, functional beauty is a good thing. I never felt real confidence that a china girl build was going to get me home again as an almost certain thing. Your Mongoose would make someone a great commuter.

Regarding a kit to fit a number of different frames... one for a beach cruiser would be good as there are so many of them, new and old. I read about all of the problems newbies have with the rag joint, cheap parts breaking, motors that never were right from the beginning and I feel for them. A number get turned away before they barely got started and missed out on what could have been a lot of fun, inexpensive miles of smiles. Too bad. A well made set of hardware and clear instructions (in English) along with a how to video link and it would be a winner. Enough people riding four stroke motorbikes and it would make a difference for the whole country. Why drive a truck to work when a motorbike will do as well and is more fun? But it is not fun if it doesn't get you there or leaves grease on your work clothes, etc. I think your scissors clutch (not really a clutch) mount along with a 98cc Predator would be a great introduction to the world of motor bicycling.

And mounted on a ladies bike (step through) makes it perfect for an older rider. The pull start on a 98 Preddy is so easy that anybody still alive can start their engine. And being low compression it would no doubt be a breeze to bump start. Minimize the hassle, maximize the fun.
SB
 
Ludwig II

Ludwig II

Well-Known Member
Jul 17, 2012
5,071
783
113
UK
One thing that is missing from the market is a kit to convert a 2 stroke into a narrow unit suitable for mounting in a bike frame. The pull start sticks out on one side, and the clutch is on the other, even before you start adding a transmission. Whether it's for a "universal" bolt spacing, or to fit a specific gardening motor, I think there's a niche for it.
 
Ludwig II

Ludwig II

Well-Known Member
Jul 17, 2012
5,071
783
113
UK
Let's think it through. What needs to be sticking out of the engine? A short shaft to take a chain, belt or gear drive. Does it need the ignition actually on the crankshaft? No. Worry about it later. Does it actually need a fan if we can increase the fin size/area? No. Bin it.

Do we need a reduction drive and secondary shaft? Probably, call it 4:1, and fix a 4 trigger rotor to the back of it.

Clutch, option of manual or 2 way auto at the output end of the shaft.

Take a look at how thin you could make it.

 
cannonball2

cannonball2

Well-Known Member
Oct 28, 2010
3,682
221
63
Colonial Coast USA.
L2, what area are you wanting to source engines from? You are showing a set of hand held cases. Is that the basis? 2strokes have been disappearing due to emissions/not green stigma. The larger Tecumseh 2stokes were good engines to build a bike around as well as the Suzuki mower engine. They would inframe quite easily. But they are history except for scrounging. If new is a must then at least on this side of the pond its pretty much down to hand held engines. At least there are still 2stroke chainsaws!
 
Ludwig II

Ludwig II

Well-Known Member
Jul 17, 2012
5,071
783
113
UK
Well, Europe isn't in quite the same fear of tree huggers, so we can get 2 strokes. I reckon that if the market is big enough for a whole small industry to exist supplying China Bombs, then there's enough opportunity for a conversion kit to sell to fit modern and more reliable designs.
 
Ludwig II

Ludwig II

Well-Known Member
Jul 17, 2012
5,071
783
113
UK
Train of thought: Minimoto engine with the reed valve, fit a Walbro type carb. Turn engine 90deg to the crankshaft is in line with the frame, with the cylinder vertical. Now produce a 4:1 bevel box to run the dive out to the left, but not too far. Those are the only alterations necessary to any existing engine. and maybe tone the porting down a bit, and lower the bite point of the clutch.
 
  • Like
Reactions: techicaldaydreams
You must log in or register to reply here.
Top Bottom