D
Dan Hunter
Guest
As I stated in the introduction, this project started with my desire to get my daughter a gas-powered scooter. I settled on a Visa Viper as I liked the chain drive and the simplicity of their gearbox along with the Honda engine option. While in Korea on a one year remote, I watched a gentleman washing client cars on base. His transportation was a bicycle with a friction drive engine on the front tire. I wanted to build a bike with the Visa gearbox/engine combination but had a more integral appearance. I spent a bunch of time researching part combinations and measurements until I couldn’t think it through any further.
I got back to the states and just couldn’t let it alone. I started acquiring parts for events…birthday, Christmas, whatever. It took a while and my wife was fairly certain it wasn’t going to happen. With all the parts accumulated, I started cutting frame parts and taping them together to make sure the geometry was correct. The intent was to allow the engine to be serviced without removal, driving a rather long wheelbase. The frame was MIG welded together. Much of it was free handed with lots of eyeballing and measuring. The lower portion of the frame was absurdly over-engineered; I have the steel in the garage for a second frame which will use an aluminum adapter plate and bungs on the frame to simplify the process and lighten the frame.
The steel was purchased at Aircraft Spruce. They cut to reasonable lengths for shipping and offer a large selection. That’s an Brooks B17 English leather riding saddle; based on the price, they were rather proud of it. I purchased a 68mm bottom bracket from Gaerlin in California along with the True Temper head tube and Surly dropouts for the rear axle. The Surleys are great because they allow you to adjust the chain tension with fore/aft axle shift. If I could find Answer BMX parts I used them as they made solid quality parts for a reasonable price. I used short Dotek crank arms as the pedals were only to get it moving so I wouldn’t smoke the clutch. I purchased a previous year model Manitou fork for a massive discount. Note it’s a disc only fork. The original brake was a Hayes unit but the lousy thing wouldn’t seal (cheesy design) so I replaced it with a Shimano Deore mechanical brake that works just fine. A key part of the bike is the Staton-Inc hub that allows me to drive on the right side with the pedals and the left side with the engine using an ACS Southpaw. The hub is also over-engineered with four bearings. I had Dave ship the hub directly to Gaerlan and they laced it up to some Sun Rhinolite wheels and slick high pressure Kenda tires to keep the rolling resistance down. That’s also where I sourced the Shimano Deore hub for the front disc. I modified a two finger front brake lever to pull the throttle cable and put the disc brake on the left grip.
The performance is pretty much what I expected. Because left side freewheels are in little demand, there’s equally little choice in tooth count and as it stands, my gear reduction is about 15:1. The engine just isn’t getting a chance to operate at a high enough rpm to take full advantage of the available power. My daughter doesn’t know the difference and operates it at real speed. I weigh about 225 and it’ll hold 22 mph but struggles into headwinds common in Oklahoma. If I could have attained 21:1 or so, I think could have gone with a 24” wheel instead of the 20” wheels and probably done better at targeting a good rpm. I’m looking at swapping Staton hubs and locking a fixed Azusa sprocket which should settle the issue. Also, I’m looking to replace the water bottle fuel tank with a chromed aluminum tank similar to those used as extended range tanks for motorcycles. I’ll probably just pay for a custom one with integral mounts and an offset fuel fill to allow me to mount it underneath the toprail.
It’s been a lot of fun to assemble but mostly satisfying to take from concept to reality.
I got back to the states and just couldn’t let it alone. I started acquiring parts for events…birthday, Christmas, whatever. It took a while and my wife was fairly certain it wasn’t going to happen. With all the parts accumulated, I started cutting frame parts and taping them together to make sure the geometry was correct. The intent was to allow the engine to be serviced without removal, driving a rather long wheelbase. The frame was MIG welded together. Much of it was free handed with lots of eyeballing and measuring. The lower portion of the frame was absurdly over-engineered; I have the steel in the garage for a second frame which will use an aluminum adapter plate and bungs on the frame to simplify the process and lighten the frame.
The steel was purchased at Aircraft Spruce. They cut to reasonable lengths for shipping and offer a large selection. That’s an Brooks B17 English leather riding saddle; based on the price, they were rather proud of it. I purchased a 68mm bottom bracket from Gaerlin in California along with the True Temper head tube and Surly dropouts for the rear axle. The Surleys are great because they allow you to adjust the chain tension with fore/aft axle shift. If I could find Answer BMX parts I used them as they made solid quality parts for a reasonable price. I used short Dotek crank arms as the pedals were only to get it moving so I wouldn’t smoke the clutch. I purchased a previous year model Manitou fork for a massive discount. Note it’s a disc only fork. The original brake was a Hayes unit but the lousy thing wouldn’t seal (cheesy design) so I replaced it with a Shimano Deore mechanical brake that works just fine. A key part of the bike is the Staton-Inc hub that allows me to drive on the right side with the pedals and the left side with the engine using an ACS Southpaw. The hub is also over-engineered with four bearings. I had Dave ship the hub directly to Gaerlan and they laced it up to some Sun Rhinolite wheels and slick high pressure Kenda tires to keep the rolling resistance down. That’s also where I sourced the Shimano Deore hub for the front disc. I modified a two finger front brake lever to pull the throttle cable and put the disc brake on the left grip.
The performance is pretty much what I expected. Because left side freewheels are in little demand, there’s equally little choice in tooth count and as it stands, my gear reduction is about 15:1. The engine just isn’t getting a chance to operate at a high enough rpm to take full advantage of the available power. My daughter doesn’t know the difference and operates it at real speed. I weigh about 225 and it’ll hold 22 mph but struggles into headwinds common in Oklahoma. If I could have attained 21:1 or so, I think could have gone with a 24” wheel instead of the 20” wheels and probably done better at targeting a good rpm. I’m looking at swapping Staton hubs and locking a fixed Azusa sprocket which should settle the issue. Also, I’m looking to replace the water bottle fuel tank with a chromed aluminum tank similar to those used as extended range tanks for motorcycles. I’ll probably just pay for a custom one with integral mounts and an offset fuel fill to allow me to mount it underneath the toprail.
It’s been a lot of fun to assemble but mostly satisfying to take from concept to reality.
Attachments
Last edited by a moderator:
say, Dan...that's a NICE bike!
