Junk Yard Dog Makeover

[Dave31]

If any you remember my J-dog (pics 1&2) it started off as a friction drive then went to a chain drive using a 31cc Zooma motor. I ran a 48,42 and the last was a 36t sprocket with top speed around 32mph with a little help of pedal power but was gutless going up any hill but with the assist of pedal power was okay.

I had to strip some parts off the J-dog to get my Rockhopper ready for the DR Oct.31, I was also having carb problems with the Zooma motor that I never got the time to figure out what it was and ever since the J-dog has been sitting collecting dust.

I had to get another rear wheel for the J-Dog because I destroyed the one off it on the Rockhopper doing some testing for the D-Race. But, I just noticed that it is missing and I think one of my bastard friends decided to help themselves to it, so no one will fess up I will have to get another wheel.

Thanks to a really cool guy I have acquired a 50cc motor for the J-Dog that will give me a little extra HP (pics 3-5) and make going up those AZ hills a little easier.

The fuel tank will have to be swapped over to the other side as well as the motor. One dilemma I am having is if I should use the left side of the wheel for the drive with a rag joint(current set-up) or I can weld a sprocket to the last sprocket on the cassette and use that for the pedal drive and motor drive.

Using the left side with a rag joint I would have to raise the motor to be able to clear the exhaust with the rear wheel and rear rack. Using the cassette to drive the motor off will have the motor hanging off the side more then I like. But I will eliminate the rag joint and have plenty of clearance for the exhaust.

Another issue I am having is the fuel tank is gonna have to sit pretty high in order for it to feed the carb correctly. But by mounting the motor to the right using the cassette as a drive I will be able to mount the motor lower thus being able to mount the tank lower.

J-Dog Videos:
YouTube - Motorized Bicycle along the Santa Cruz River No 2

YouTube - DIY Motorized Bicycle in Silvercroft wash

YouTube - Motorized bicycle along the Santa Cruz River

 

[Dave31]

Pics 1 & 2 Using rag joint left side of wheel?

or

Pics 3 & 4 Using cassette right side of wheel?

Decisions,decisions........

 

[Dave31]

Here is the ideal I have of attaching the sprocket to the cassette. This will still give me 4 gears for the pedals.

I can either make some tabs and bolt it to the cassette, or just weld it on there and be done with it.

 

[corgi1]

How will u pedal that fast?
if it is on the right it will run the crank gear

 

[Dave31]

How will u pedal that fast?
if it is on the right it will run the crank gear

You know I never considered that lol

Thank You for pointing that out lol

 

[Dave31]

I was just thinking I have an old Murry Mt. Bike frame, maybe I will just mount it center frame and widen the pedals to clear the motor.Hmmmmm............

 

[Dave31]

I was just thinking I have an old Murry Mt. Bike frame, maybe I will just mount it center frame and widen the pedals to clear the motor.Hmmmmm............

Well after looking at it that wont work unless I want to cut my leg off with the chain, the motor is just too wide.

 

[Dave31]

This is kinda how the motor will mount. It will be adjustable left and right, and up and down. Still not sure what I am going to do about the tank but I will work that out when I get to it.

 

[Dave31]

Small progress...................

Made the mount for the motor. Still need a rear wheel that one is damaged too bad so just using it mock everything up.

I think next I am going to make the exhaust and was thinking about using a small fire extinguisher, not for performance or anything just to give it that strange look. I just got to find something to use as exhaust tubing and something to make the flange to bolt to the motor.

 

[Dave31]

Here is what I was thinking for the exhaust. Maybe I will do maybe not, we will see....

 

[diceman2004]

the little lawn mower tip will work nice to quiet it down ( i tried both the small one and big one on my 4 stroke , the small one is much quieter ) , and that extinguisher should make for a good expansion chamber .

how much reduction are you getting off that gear box ?

 

[Dave31]

the little lawn mower tip will work nice to quiet it down ( i tried both the small one and big one on my 4 stroke , the small one is much quieter ) , and that extinguisher should make for a good expansion chamber .

how much reduction are you getting off that gear box ?

To be honest I have no ideal what the reduction is, never checked. Does not seem like much though but it does help. Gas Scooter Transmission

I was getting over 30mph with the 31cc and a 36t sprocket, I plan to stick with the 36t but I might go back to the 42t.

 

[NEAT TIMES]

david, i think it is 5.1 ratio gear box. your memory is like mine, very good, but short. do you remember the guy with the friction drive? Ron

 

[Dave31]

david, i think it is 5.1 ratio gear box. your memory is like mine, very good, but short. do you remember the guy with the friction drive? Ron

I did do a bench test before I mounted it but yeah you might be right Hopefully soon I can get some time to double check and get the J-Dog running again.

 

[Dave31]

Good news and bad news

Good: I finally got the real wheel for $2 at Bicas

Bad: Went to fire it up and run it for a few minutes to check my chain alignment and the first pull the dang thing broke.

 

[NEAT TIMES]

David, Wow. Reminds me of what the farmer said when his cow died ; "She never did that before". Now you know why it was gave to you. It`s a bummer for sure. They have the complete unit in aluminum on ebay, but will be around $25. w/sh. If I had a spare , would send it . Good luck. Ron Ps, The nascar bud shoot out race starts at 6 pm eastern time tonite. .

 

[Dave31]

Yup does suck but I will figure something out.

Watched every lap buddy, I even watched the Danica Patrick 200 earlier today

 

[NEAT TIMES]

Did not know about the Danica race, that is a bummer.

 

[Dave31]

Did not know about the Danica race, that is a bummer.

The ARCA race, but all they talked about was Danica

 

[Dan]

First time we spoke Fair was about this build. I am looking forward to see where you go with her. I really think a "saddle Mount" Is the way to go. Leaves ya with a bike with an engine. Vibes and noise behind ya and normal sized cranks. Is a great concept.