Electra Rat Fink ... Suitable for a 1st build?

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Ono Nadagin

New Member
Mar 19, 2014
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Fort Worth, Texas
I have been lurking in the forum for a lil while now, my father wants to build himself a motorized bike to ride around car shows and swap meets.

Then the other day while looking looking for suitable bikes for a few weeks we stumbled across this at a pawn shop

It has a 3 speed shimano hub iirc would like to work gears into it... maybe not at 1st but it would be cool.

Want to add a disk break to the front

possibly a disk break on the jack shaft

Ok and now to my most noobish question... Whats the diff between these transmission and jack shafts coming off the motor as they look a lot alike to me other that some are belt some are chain... like one of the like a jackshat vs a EZM Qmatis or some other transmission





So we were thinking of a 4 stroke 79cc Predator mounted vertically like some here have done... namely Scotto and Atombikes or a 2 stroke chinagirl

here is the Atombike post that got me thinking about a 4 stroke.

atombikes said:
Per motorbicycleracing's request, a couple more pics of mounting options, this time with wheels on to give some sense of level.

First is the engine with mounting oriented to the seat tube:



I think this vertical mounting will look great in this Rat Fink frame especially with its seatpost already laid back and it avoids mounting by drilling through the frame that I have seen break a couple of these Rat Finks while searching diff forums

I am guessing it is gonna cost a bit more to go the 4 stroke route but my Dad even tho he is in his 70s I think once done the 4 stroke will give him the less to no hassle riding he wants and gets from his FLHT Harley bagger he still rides daily

So 2 stroke or 4 stroke?

I have read a lot but now that we a re waffling between a China Girl or a 4 Stroke I am kind of on info overload.

I will have more questions, just kinda wanted to get the ball rollin with this post.

Thank you in advance

Ono

Edited to say forgive the time and date on the pics his VCR has the wrong time on it too... JK love ya Dad ;)
Click to expand...
 
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maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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memphis Tn
Well, I'm normally a hardcore two smoker but that frame would be very sweet with a thumper. The only issue I see is the need for a jackshaft to use the geared hub, especially if you use a HF engine since they are not standard in fourstroke kits.
Pretty much any geared build will perforce be custom.
You might co0nsider running a single speed rear wheel and a standard kit until you get more experienced and know what's involved.
But either way, it's a very nice platform for any motor build.
 
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Albula vulpes

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Mar 16, 2010
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FL
Too nice of a bike for a china girl. Too nice of a bike for a 1st build. Your mechanical skills might be better than mine though.
 
wheelbender6

wheelbender6

Well-Known Member
Sep 4, 2008
4,059
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TX
I agree with Albula. The Rat Fink is a collectable bike in my opinion, so I wouldn't motorize it.
A first build goes easier with a kit engine on a steel mountain bike or beach cruiser.
There are fewer problems to solve and you will not have to fret over scratching that beautiful Electra paint.
 
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insomniacshotrods

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Sep 26, 2008
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Its not super easy, but its not that hard. Both were bought for $100 each from a girl I work with. She said they gave $600 each. To make a long story short I got the white seat one for $25 after a buddy gave up motorizing it, and took apart the 3 spd rear and couldnt get it back together. I built that one for another buddy . I had to make the exhaust out of conduit and make up front motor mount and offset motor some and use extra spacer on the sprocket. Also made intakes for both and a front fork mount gas tank for mine. My rat fink has the sbp shift kit on it using the stock 3 spd. His has the handle bars off mine, I put drag bars on mine. I like the way his single speed starts by popping the clutch and it rides like a caddy with the apes on it. Both run great shifting can be a pain on mine and its hard to peddle start with the high compression head. I now have a headlight on his.

 
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birdmannn101

birdmannn101

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Oct 23, 2011
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Indianapolis, IN
I have been lurking in the forum for a lil while now, my father wants to build himself a motorized bike to ride around car shows and swap meets.
Click to expand...
Ono, Just so your father doesn't end up unhappy, you might check with your car show and swap meet people first. Here in Indiana you have to be handicapped to ride anything around in these gatherings.

Dan
 
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insomniacshotrods

New Member
Sep 26, 2008
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True at events like Goodguys and NSRA meets you can not ride bikes ect. unless as stated or handicapped and then you can rent a cart from them.. Cruise nights on the other hand or local shows don't care, so build it and show it help others get into it. I got a third place in a big yearly show in my home town with my ratfink bike and have never won anything with all the different cars ive placed ha. Plus it was easy to load and lots of questions asked about it.
 
Chainreaction

Chainreaction

New Member
Dec 14, 2014
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Tulsa OK
Definitely 4 stroke. Can you imagine putting along and with your noisy little 2 stroke loading up and you have to rev up it up a few times to clear it out, in the process blowing blue smoke all over someones pride & joy?

Low geared 4 stroke with a centrifugal clutch sounds like the way to go.
 
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insomniacshotrods

New Member
Sep 26, 2008
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Ive never had any of those issues with the china baby over the 6 yrs that ive been playing around with them. No wonder your loving the 4 stroke I would too. Im gonna build a 4 stroke bike someday, they look good and sound like fun too. I used to love to ride my minibike with the Briggs and Stratton on it. Ive only ran 1 kind of oil mix since starting this hobby with the 2 stroke and thats the Opti-2. I put a packet in a gallon of gas and it is good for any mix ratio. I wasn't so sure on it when the chainsaw repair man told me it didn't matter what ratio this will work. I told him I was breaking in a engine and it needed to run richer , he said dont matter . Ive never had any problems with my 4 bikes or the many ive helped build , we all use one packet to one gallon of gas. No smoke, no burned rings, no fouling, no problems I have over 700 miles on mine so far, so im a believer.
 
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Ono Nadagin

New Member
Mar 19, 2014
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Fort Worth, Texas
I hate to tell you guys he decided he wanted to go electric on the Rat Fink bike using a 48v 750w Bafang mid drive electric motor that mounts through the cranks bottom bracket so it is very discreet. After reading more about the Rat Fink we thought it best not to molest the 1st series all orig and totally perfect all steel 1st gen Rat Fink

Batteries will go in an old small white antique Frosty's Root beer cooler mounted on a rack behind the seat.

Here is a pic of the Bafang motor on a bike



And I am taking over a build of a Giant Stiletto it has a built in jack shaft and will be much easier for me to get finished. a buddy gave me a Sposter tank for free and I think it looks great on the bike


I am going to use a few of those dune buggy billet mounts to tile the motor mounting plate to the frame


BTW I am looking for another rear fender for this Stiletto I am going to reverse it and put it on the front with the pointy end forward
 
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