I call it Buzzbike

Urban Fatbiker

Well-Known Member
Local time
1:15 PM
Jan 30, 2019
Nashville TN
I have finished my rework and this is the build thread for "Buzzbike". My idea with this build was simplicity...yeah right. I wanted to do a friction drive and construct it so it could be moved to a different bike. I didn't like the offset engine, so I had to center it. I also wanted to use a larger diameter roller, so that meant reduction drive. Some of the other thoughts were I needed freewheeling, and ability to pull-start and roll-start. I made a mount frame out of part of a rear swingarm of a 20" suspension bike, I also used the triangle shock pivots as part of the 'toggle clutch' to lift roller off wheel.

Power is Ryobi 30cc 2-stroke. I made an exhaust for it, works fairly well, nice dirt bike sound.

Drive roller is a rubber sleeve 2 1/4" diameter (garbage disposal coupler) mounted onto PVC fittings with brass reducer end fittings screwed in, M14 x 180mm cap screw shaft. Bearings and aluminum end caps salvaged from a 750W PMA servomotor scrapped from industrial robot. Serious hi-RPM continuous duty sealed bearings. The mount is pivots screwed to the dropout rack / fender mounts, and a section of seatpost sleeve / rear triangle mounted to seatpost and welded arms screwed to the rack mount hard points.


Roller and bearing caps assembled to weld the cage.


Cage welded.


Assemblies painted. Roller and shaft assembled with bearings pressed, rubber clamped for gluing.
And the finished product assembled, ready for road testing. As I have already been riding it before I reworked it, I have full confidence in the mission tomorrow for the first rework road ride. Clear the street please. Spring is here.


Front view, dual brake lever, locking clutch lever, friction shifter thumb throttle, kill switch.


Rear view, toggle clutch triangles and struts. Shadow of end caps make the roller look funny.


Clutch side, good view of homemade muffler. The chamber has inner baffle and outer shell. Note the clutch lever forces the triangle to rotate, lifting the assembly with the roller. Engine is on pivot mount with spring tensioners under the platform. You can also see a spring that keeps tension on the drive roller.


Drive side, sprocket drive reduction. You can see I gutted the clutch and used the inner as mount to weld the sprocket. I made the engine platform two-piece in case I might build a different mount for a different engine. The mount holes for the lower platform are slotted for alignment of drive sprocket with roller sprocket. All large pivot mount nuts are nylok.

Going riding tomorrow. Wish me many more miles of fun. For a project that started as a way to make something out of scraps, did pretty good I must say. Already had over a hundred miles on the original metal roller and crappy end caps before this rework. I'm hoping the rubber roller will keep some wear off the tire. It won't be that easy to replace, but it was made to disassemble and replace. 4 bolts remove the assembly, 4 bolts to break apart, cut sleeve off and glue new sleeve on. Simple...I think. Hopefully I won't have to test that for a few hundred miles. If I am wrong...I do have the steel roller to re-install, same dimension.
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Oh yeah...the gray bottle. Extra fuel. I ride until I ran out of fuel, dump the bottle in, go home. May need to pedal more on the return, its not quite a FULL tank.

I looked at the finished product, and was a bit miffed that I didn't chop out the second holes on the lower engine platform. They looked like they didn't belong. Well...when I went to hang my AAA light, that was perfect to hand a side light. Gonna add another to the right side. Now the holes look like I planned it that way. I like it when a screwup becomes a feature!!!
That's some awesome framework there, I like how you kept the weight and mass of the engine mostly within the bike centerline, as opposed to how most FD engines hang off one side of the bike. I think the exhaust is over the top, but it goes with your horn LOL

Good times!
To be technically accurate, the exhaust is over the top and off in the left field :ROFLMAO:

I played around with some different configs, one had two cans with three smaller port tubes. Way too much. It takes a lot to get a good muffled deep note w/o restriction. I gotta make a video. The sound of the low-note popping is worth the gaudy look. I can't wait to pull up beside a Harley and rev it like some kind of fool. And give it that crazy grin that scares people. 🤣😬😠👹

The exaggerated dimensions add that sarcastic attitude. Goes with my Urban Fatbike and a recumbent that looks like a mobile deer stand.

Next project is a longbike recumbent with mid-drive bottom bracket, running chain drive thru the mid-crank for some evil shifter capability.

That's some awesome framework there, I like how you kept the weight and mass of the engine mostly within the bike centerline, as opposed to how most FD engines hang off one side of the bike. I think the exhaust is over the top, but it goes with your horn LOL

Good times!
Right now, about 20mph. I had it geared higher, running 30mph, but with one gear your choices are speed OR torque. So I swapped to a larger driven sprocket to climb the hills.
This is by far the cleanest, most gorgeous friction drive build I think I have ever seen. I love the use of re-purposed parts and how you have it set up to engage/disengage from the tire.
PS: I have wanted to see a shifter friction build for a long time, and I do believe you have the skill to pull it off. Trike internally geared hub, its basically a jackshaft. You can get your 30 mph back and then some maybe, while keeping hill climbing power and dead stop acceleration ;).
Hmmm. Bury a shifter hub in the roller, inboard sprocket...hide the shift lever from the popo. Hard to hide a chain shifter.

Rethinking that next build. Gonna buzz around tomorrow and think on it.

Still have a video to make too. I did swap my roller back to the steel roller, rubber and PVC wasn't holding up. The steel one is already proved itself. Glad I thought ahead on that one, and intentionally kept the same dimensions. I did replace the crappy end caps of old roller with metal. I'll add a pic of that tomorrow.
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