dumpydoodoo
Member
Good looking machine.
Shanghai Scrambler
- Thread starter wrenching4fun
- Start date
wrenching4fun
Well-Known Member
wrenching4fun
Well-Known Member
Some of you might be wondering what happened to the ole Shanghai Scrambler from a while back. That project was abandoned for the JC Higgins springer with a Honda GHX50 I called the Way Back Machine because the Higgins was circa 1950. That bike is basically finished and serves as my daily rider, but the itch to build never seems to go away. After inventorying all of my "spares", I decided to resurrect the Scrambler but instead of making it as complicated as humanly possible like the Higgins, I decided to go as simple as humanly possible.
Here's the donor bike, previously the Scrambler, stripped down to its bones except for mirrors and throttle.
I decided to use my trusty old Huasheng with a friction roller made from the core of a Shimano gear cassette. Welded keyed 5/8" steel collars on both ends to affix to the output shaft.
Here's a closeup of the roller. It looks just like the factory roller on my vintage Bike Bug.
The major part of the build is constructing the mounting system for the engine. The chrome tubing rotates on the rear axle to raise and lower the roller from the rear tire. So far I've only mocked up the legs and mainframe that the engine mounting plate will be welded onto.
Here's the donor bike, previously the Scrambler, stripped down to its bones except for mirrors and throttle.
I decided to use my trusty old Huasheng with a friction roller made from the core of a Shimano gear cassette. Welded keyed 5/8" steel collars on both ends to affix to the output shaft.
Here's a closeup of the roller. It looks just like the factory roller on my vintage Bike Bug.
The major part of the build is constructing the mounting system for the engine. The chrome tubing rotates on the rear axle to raise and lower the roller from the rear tire. So far I've only mocked up the legs and mainframe that the engine mounting plate will be welded onto.
wrenching4fun
Well-Known Member
Experienced a glitch on previous post, so here is the rest of it. The standard mounting plate for a Huasheng (scavenged from the Scrambler build) will be extended to fit the geometry for this build before being welded to the downplate extending from the crossmember. All will make more sense
once I get everything tacked together.
I'll have to fabricate scissor-type mechanism on the engine mount so the roller can be raised and lowered to engage and disengage the tire. Then it's simply a matter of connecting the kill switch to the engine and testing everything out. The engine is totally self-contained so there's no gas tank to mount and no sprockets, clutches or chains to install. I'm on the fence about lights. What do you think?
once I get everything tacked together.
I'll have to fabricate scissor-type mechanism on the engine mount so the roller can be raised and lowered to engage and disengage the tire. Then it's simply a matter of connecting the kill switch to the engine and testing everything out. The engine is totally self-contained so there's no gas tank to mount and no sprockets, clutches or chains to install. I'm on the fence about lights. What do you think?
wrenching4fun
Well-Known Member
Liking the way this build from spare parts is coming together. I especially like the simplicity of a friction design. No purchases necessary so far and it's near completion. Will post photos soon, since the previous ones no longer apply.
wrenching4fun
Well-Known Member
The only purchase on this build so far has been a one dollar stainless steel water bottle from a thrift store to carry reserve fuel.
Aluminum mountain bike frame with double-walled aluminum wheels with disc brakes and Magic Mary tires. 10 year old Huasheng 142F powerplant was sitting on a shelf collecting dust. It still runs great after several years of use on another build. It's rocking the Keihin carb from my Honda GHX50 that now powers the Way Back Machine. The seat, gooseneck, and handlebars are spares from the parts bin.
Heavy angle iron from an old Sears Rototiller was used to fabricate the engine rack. Pivot points were welded to a four-stroke kit engine mounting plate which swings away from the tire to disengage the friction roller which was made from the core of a Shimano gear cassette. The stock fuel tank from my Honda GHX50 water pump fits perfectly on the Huasheng making it a completely self-contained unit. I fitted the cap with a vent tube and routed the hose thru the engine mount to channel spilled fuel away from the exhaust.
Two views of the roller in the engaged position. To disengage, the engine pivots forward creating 1/2" of space between the roller and the tire.
The engagement/disengagement arm is a section of handle from the Sears tiller. The pivot point is spring loaded so it can swing away from the keeper that holds it in place when the roller is disengaged. The mount is another section of angle iron screwed to anchor points for a water bottle holder. The keeper is held to the top tube with a 1 1/2" diameter forward footpeg clamp from my old Harley Road King. The linkage is made from threaded rods and a small diameter steel rod connected to an fulcrum made from aluminum plate.
Throttle linkage isolates the cable from the mount so the throttle position is not effected by the engagement arm. Coming up with this work-around literally made my brain hurt, but it works great!
Final steps before testing includes installing a set of square-holed pedal shafts, installing a pedal chain, connecting the rear brake caliper and cable, wring the kill switch, and fabricating a drop-down kick stand to handle the offset weight of the engine.
I built one of these 12 years ago using a 96 cc snow blower engine mounted to a Huffy that had been rode hard and put up wet! It was a lot of fun, but turned out to be a death trap with a worn coaster brake and ratty tires. The frame self destructed due to vibration and stress from the powerful little Tecumseh 2 stroke.
Aluminum mountain bike frame with double-walled aluminum wheels with disc brakes and Magic Mary tires. 10 year old Huasheng 142F powerplant was sitting on a shelf collecting dust. It still runs great after several years of use on another build. It's rocking the Keihin carb from my Honda GHX50 that now powers the Way Back Machine. The seat, gooseneck, and handlebars are spares from the parts bin.
Heavy angle iron from an old Sears Rototiller was used to fabricate the engine rack. Pivot points were welded to a four-stroke kit engine mounting plate which swings away from the tire to disengage the friction roller which was made from the core of a Shimano gear cassette. The stock fuel tank from my Honda GHX50 water pump fits perfectly on the Huasheng making it a completely self-contained unit. I fitted the cap with a vent tube and routed the hose thru the engine mount to channel spilled fuel away from the exhaust.
Two views of the roller in the engaged position. To disengage, the engine pivots forward creating 1/2" of space between the roller and the tire.
The engagement/disengagement arm is a section of handle from the Sears tiller. The pivot point is spring loaded so it can swing away from the keeper that holds it in place when the roller is disengaged. The mount is another section of angle iron screwed to anchor points for a water bottle holder. The keeper is held to the top tube with a 1 1/2" diameter forward footpeg clamp from my old Harley Road King. The linkage is made from threaded rods and a small diameter steel rod connected to an fulcrum made from aluminum plate.
Throttle linkage isolates the cable from the mount so the throttle position is not effected by the engagement arm. Coming up with this work-around literally made my brain hurt, but it works great!
Final steps before testing includes installing a set of square-holed pedal shafts, installing a pedal chain, connecting the rear brake caliper and cable, wring the kill switch, and fabricating a drop-down kick stand to handle the offset weight of the engine.
I built one of these 12 years ago using a 96 cc snow blower engine mounted to a Huffy that had been rode hard and put up wet! It was a lot of fun, but turned out to be a death trap with a worn coaster brake and ratty tires. The frame self destructed due to vibration and stress from the powerful little Tecumseh 2 stroke.
kOOL, should last a long time..........Curt
wrenching4fun
Well-Known Member
Thanks, Curt. What are you working on at the moment?
House, redo some of the trim and painting. I am about to start on a frictin drive that I bought that was built in the 50's. I had to find a fork and a couple things, the emgine has been soaking for a couple years to get some rust out. Now that we will be done with the house soon, and am cleaning garage i will have to get it together and in one piece, running..........LOL....Curt
wrenching4fun
Well-Known Member
Vintage bikes are fun to work on. Are you going with a China Doll? I gave my trusty 66cc to my nephew, so I only have 4 strokes except for a 80cc Sachs 2-speed moped engine.
It's a old Briggs washing machine motor with a old car generator with the side cut out for frictiond drive, should be fun......Curt
wrenching4fun
Well-Known Member
Is the Briggs a cast iron kick start version?
No it is not, but the replacement if this one don't workout has a kick start, this one is wind the rope and pull. I have a few old engines in my stach, soon to be sold, my sons don't have much interest in this stuff............Curt
wrenching4fun
Well-Known Member
Got in trouble as a kid for cutting off the end of mom's broom handle to make rope starters! Rope starts are a good incentive to keep your engine tuned.
For sure, that would do it....LOL........Curt
wrenching4fun
Well-Known Member
Have thoughts of a build around a kick start Briggs, an Iron Horse, a Maytag 72 hit 'n miss, or an opposed-cylinder outboard engine. Let me know when you post yours for sale.
wrenching4fun
Well-Known Member
Would like to take it off your hands, but shipping is prohibitive these days.
wrenching4fun
Well-Known Member
Removed the freewheel cassette thinking all mountain bike hubs were threaded. By the time I figured out that cassette bases are built into the hub on cheaper bikes, it was too late. The works were ruined and there was no way to pedal this wheel. No sweat, I found that the threads on a lower unit are the same as a casette-ready hub so I welded it to the hub and a single speed freewheel screwed right on.
Although I found a good lower unit in the parts bin, I couldn't locate a crankset or 9/16 pedals. My local pedal parlor set me up with a nice Shimano crankset and heavy duty pedals. I degreased the old JC Higgins chain with gasoline and WD-40 then soaked it in oil to round out the drive train. Most people throw these rusty chains out, but it's easy to resurrect them if they're not too far gone. I figure my tired old legs are probably 1/10 horsepower, so I should be okay.
The hefty dropouts are designed to handle a drop down kickstand which I intend to construct from scrap metal. The light channel from flat screen TV wall mounts is perfect for this. Have been unable to locate one at the local thrift stores so far.
It's amazing how many spare parts I've used on this build.
Tomorrow will be the first test ride.
Although I found a good lower unit in the parts bin, I couldn't locate a crankset or 9/16 pedals. My local pedal parlor set me up with a nice Shimano crankset and heavy duty pedals. I degreased the old JC Higgins chain with gasoline and WD-40 then soaked it in oil to round out the drive train. Most people throw these rusty chains out, but it's easy to resurrect them if they're not too far gone. I figure my tired old legs are probably 1/10 horsepower, so I should be okay.
The hefty dropouts are designed to handle a drop down kickstand which I intend to construct from scrap metal. The light channel from flat screen TV wall mounts is perfect for this. Have been unable to locate one at the local thrift stores so far.
It's amazing how many spare parts I've used on this build.
Tomorrow will be the first test ride.
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