Hey guys! Thanks to everyone for the great information already posted. By searching Google for so many answers, tips, suggestions, and ideas, I have used this forum for countless hours across the last 6 months. After one electric bike and 3 gas motor builds I have decided it is time to join the forum and share my experience.
Bicycle: Currie E-Zip
I needed to get around in dress cloths without sweating, so I started with an electric bicycle. $450 from Walmart and no modifications required out of the box. At first this bicycle went about 15mph for 6-10 miles without any pedaling. After 3 months the battery would not charge enough to ride more than a mile. I priced a new battery from Currie and it was $150. Seeing this as a likely recurring issue, I sold the electric bike for $200 and decided to go with something that didn’t need charging.
Bicycle: Schwinn Point Beach
Engine: 80cc slant head kit from Powerkingshop on ebay.
I kept fixing the things that broke until I felt I had everything bulletproof:
1)Replaced the clutch lever with a motorcycle lever
2)Replaced twist grip with a thumb throttle and external kill switch
3)Replaced crank arms with a wide crank
4)Replaced all of the bike’s bolts/nuts with stronger bolts, locknuts, and rubber washers
5)Added springer fork for suspension and added disc brake
After adjusting the carburetor’s float arms, I now had a 38 mph bike on flat land with 40mph maxed out downhill. I rode the bike for a couple of months until one of the engine mount studs broke (I hadn’t upgraded these). I was unable to extract or drill out the stud, so I had to set the motor aside.
Bicycle: (same bicycle):
Engine: GT5 from Spooky Tooth on ebay
This time I swapped engines and upgraded the studs to 8.8 grade and mounted them to exhaust clamps which clamped around thick rubber wrapped around the frame. From day 1 the engine never idled properly or had power. After contacting spooky tooth, trying all of the tips they recommended, I still had a bad motor. After a month of slow rides the powerless motor died completely.
Bicycle: 1972 Schwinn Heavy Duty
Engine: 80cc slant head kit from Powerkingshop on ebay
After never being fully satisfied with the mounting of these motors to modern bicycles with large tube frames, I decided to put my next motor on a frame that the motor was made to fit. Because the original Schwinn bicycles had 1 inch tubes, this was ideal. I bought a weathered 1972 Schwinn frame from mlmtam24 on ebay.
Here is what will work when swapping new and old Schwinn parts:
1)New American Crankset is same as old
2)New 1 Inch threaded fork is same as old
3)Headset is differentOld Schwinn has larger headset tube. Must use an original Schwinn headset (bearing cups, bearings, crown race, top race).
4)New Handlebar stem will work but you must use the new fork locknut as the old Schwinn locknut has a smaller inside hole
5)Rear fork is narrower on older Schwinn single speed. I used a new coaster wheel with a single speed and still had to adjust the wheel spacing inward to fit the narrower 1972
6)Seat post and clamp are smaller on old Schwinn. So small that i installed the seat post upside down because newer seats won't clamp down to fit the small end of the older posts.
The final product is a restored Schwinn with a motor:
1)Sanded engine fins and painted with flat black with header paint
2)Delloroto Sha 15.15 carb from Dellorto Carbs : Dellorto Carburetors, And parts for you.
3)Round aluminum 4x6 gas tank from Prodorutti Quarter Midget Supply - Welcome
4)New Schwinn decals and headbadge from ebay
5)32 tooth pedal sprocket used for engine clearance
Let me know what you think.