Rat Fink 212cc

[cmadrid40]

The project has been underway for a few (10) months now, was going to be a quick covid project that has manifested into a lot of fun with a lot of work to go...Bike is first gen Electra Rat Fink, the intention is to set it up with a 212cc Predator. This is my first bike build but I am experienced with auto mechanics and fabrication. The bike was sitting for years unused and rusting away, one of the pleasures of living close to the beach i guess. The front wheel was stolen at some point, anyway it seemed like a good candidate for a motorized bike build. I have always wanted to build a motorized bike and this was the time...i started by getting it up on the bench and remove unnecessary parts, strip off old rusted parts etc.... I found a 2.0 gal Sportster type tank that should work well, started mocking that up...the picture of the nice bike is just an example of what mine did look like 10 years ago...

 

[cmadrid40]

Getting the engine placed in frame, trying understand where mounts need to be, how the chains will work etc...

 

[curtisfox]

Going to be a KOOL build I like it..........Curt

 

[cmadrid40]

Thanks, the project is actually farther along than the currently posted images. My plan is to post a few pics with description every couple days and then i will be caught up and any further progress will be real time. I will say that some big changes were made and its looking pretty good...

 

[Venice Motor Bikes]

Here's a link to a Rat Fink that I built many years ago... I hope it gives you some ideas.

Venice- Rat Fink Chopper!!! | Motorized Bicycle Engine Kit Forum (motorbicycling.com)

 

[cmadrid40]

Awesome, that's definitley a bike I saved to my folder for inspiration a while back. Cool to know that its yours, that's a clean setup. I might have seen it here for the first time...this is my first post/ thread but have been creeping around since I started the build...good resource.

 

[cmadrid40]

Got the engine in a good spot that should work, offset to accommodate the torque converter. Most of the engine upgrades are done. A this point I was going to give up on making it a pedal bike, i was thinking about just mounting pegs i had laying around...a small motorcycle. I found some wide crank setup by mbrebel.com which should work. Mocking up the handle bar mounts...i wanted it to look like a motorcycle with double clamps and us motorcycle bars. Found 2 bolt "piston" bike stems that should work.

Predetor 212cc Non-Hemi
- Removed all the typical stuff; low oil sensor, governor...
- Added Electric Start and Battery
- Removed all pull start stuff
- MSD coil wire and "hemi"-coil looks larger...maybe more power?
- Spark Plug
- 18lb Valve Springs
- Milled Aluminum Valve Cover ported with breather
- 8 degree timing
- Back Swept Intake
- Mikuni VM24, adapter for larger filter
- KNN Filter

 

[cmadrid40]

I wanted the bottom tube to be flat with the ground so I raised the front a couple of inches...needed to make longer forks but this also allowed me to install the dual bike stems for the handle bars. Maybe ridged fork or springer...

 

[cmadrid40]

i spent a lot of time looking for ways to adapt the rear hub for a drive sprocket from engine, drive sprocket from pedals, and...disc brake mount. Ghettobike makes a real nice hub, i was trying to save money so purchased this hub off ebay...looking back probably should have just splurged for the Ghettobike, we'll see how these Chinese hubs hold up. Had to get a custom axle adapter machined, 20mm to standard 3/8" axle. Theres a great shop in El Cajon, CA for this kind of stuff and pretty inexpensive...mocking up other stuff; rear fender, head light, shocks/ coils for springer front end...handle bars are way to wide, need to trim them down.