The Conglomerate of Crap - My First Build

That will be its name for now at least...

I have a Trek 4300 that has seen a few miles and consists of parts from a number of bikes. I dont ride it anymore so I decided to have a bit of fun with it.

This will be a budget build with few purchased parts and a bit of redneck engineering - thats the way I like to do things.

I dont know if this is the standard way of doing it or not, but at this point my plan is to have a chain run from the engine to one of the chainrings on the crank and have the other two still shiftable with the regular chain and then keep the derailleur and cassette and all that normally functional. I plan to use a centrifugal clutch on the engine unless there is a better way of doing it.

My first item is selecting and purchasing an engine - preferably with the clutch already attached. I will probably go used here. Im not sure from what yet.

I am open to feedback and suggestions for easier/cheaper ways of doing things.

Now for some pics of the bike:

 

[KCvale]

my plan is to have a chain run from the engine to one of the chainrings on the crank and have the other two still shiftable with the regular chain and then keep the derailleur and cassette and all that normally functional.

As I'm sure you know the kits come with a left side direct drive system, since your motor output is counter clockwise spin on the left side and your pedals are on the right even if you mounted your engine backwards it wouldn't work, it spins the wrong way.

What you want is a Jackshaft, this transfers the left side drive to the right so you can tie it into the pedal system

Do a Forum Search for 'Jackshaft' in the Topic Title for more info but they look like this.

Just a shaft, some gears and bearings and mounts to keep it in place are cheap, but a kit with everything you need to do it right is not cheap at $200, and the reason is because of the cost of the magic parts that will keep your engine from beating you legs to a pulp when you are driving the pedal chain rings with an engine.

It's called a freewheel and it has a special pedal set that attaches to it.
In short it isolates the dual chain ring that connects the motor sprocket and the pedal sprocket from the pedals arms and crank shaft. The pedals just ratchet in place when the motor is turning the chain rings but like a socket set ratchet you can still pedal in the pedal direction.

I plan to use a centrifugal clutch on the engine unless there is a better way of doing it.

2-stroke kits have no starting system, to start them you have to spin the engine manually and bump start it, easy on a direct drive bike, just pedal up to speed and drop the clutch.

A centrifugal clutch isolates the drive from the engine so you have no way to start it unless you also put a pull start or electric start or something on it, in short if you want an auto clutch with pull start go with a 4-stroke, they come that way.

Since it is a small budget on a used bike just go with a cheap 2-stroke kit and install normally and see if you like it first is my advice.

 

[Pablo]

Wouldn't that be "Conglomeration of Crap"? That's hilarious. Sorta like my old Volvo.

 

[KCvale]

Wouldn't that be a "Conglomeration of Crap"? That's hilarious. Sorta like my old Volvo.

Hehe, ya Paul, the bottom line for Butchenrad is no mater how well he can redneck something it can't defy the laws of mechanic's and function as intended.

 

[bluegoatwoods]

Buchenrad! You're a 'fred'! Me, too......

Excellent cargo set-up there. It ought to still be workable even with a motor.

And is that a homemade rack there?

Great job!

 

[Buchenrad]

Thank you everyone for the information. I now have a much better idea of what I need to do.

Im sorry, but what is a "fred?"

Would this be a workable start for an engine and maybe some useful parts?
http://albuquerque.craigslist.org/mcy/3965625173.html

That is a home made rack. Right now its held together with bolts and nuts, but my plan is to weld it. That may or may not happen in the near future though. The nylock nuts are holding up just fine. I intend to mount the engine between my legs so I can keep my current setup - though the boxes are trashed now (those pictures are 2 years old)

 

[KCvale]

Would this be a workable start for an engine and maybe some useful parts?
http://albuquerque.craigslist.org/mcy/3965625173.html

A trashed tiny little gas engine scooter in pieces to start with?

I think I'll bow out of this topic now.
Best of luck Buch.

 

[bluegoatwoods]

A 'fred' is a bicyclist who rides something that's made for utility. A bike with racks and mirrors and such.

A lot of MB'ers are freds, whether they know it or not.

We do not wear spandex. (Though I do wear bright colors)

We have nothing against good aerodynamics. But we can, and usually do, gladly sacrifice it for good old practicality. And we consider it a good bargain.

We gladly ride in the worst weather. So we also have bad weather clothing that fits into the 'fred' category.

I'm pretty sure that the roadies mean it as a slur when they call us freds. But to us it's a badge of honor.

We are the true hard guys of the two-wheeled world.

 

[blademan]

As a fellow fred as it was defined earlier, I would like to put my opinion on this up. Sounds like you will be spending a lot more time rednecking this if you go witht the option of the god who know what's really wrong with it scooter on craigslist.
Its going to take 4 to 5 times as long to adapt the scooter motor to your bike as it will to install the kit you can get for about $200. I have looked and looked a many different alternative motorization options for bicycles. Seriously, the kit is the way to go. If you want to power the gear system get a jackshaft from sick bike parts. Bike motive makes some parts and kits that can be helpful here too, but remember that you don't need as large a gear range with a motor as you do with human power, the motor is easily 4 times as powerful as most peak athletes, so it can handle a fair amount of hills if you have it geared.
The reason I am advising the kit here is that by them time you have conglomerated this together and let's say the scooter doesn't work, then you have time and money in it you can't get back. So consider your options. If you buy a kit, buy it new. If the money is the problem, buy the motor, then save up and buy the jackshaft later. It will do better for you than conglometating things together. Have fun.

 

[KCvale]

One other thing is a kit is just parts, they just happen to be all of best right parts that play nice together, all in boxes with instructions.

Easy to do right? Heck no, but far easier with all the right parts to start with.