Why motorized bikes?

Matt Barrack

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May 30, 2017
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Just a question. Why do you ride a motorized bike? Why, if you do, prefer motorized bikes over another vehicle? Just looking for some opinions here.

Some of my reasons:
-Fun and easy to build, especially if you can't afford a motorcycle
-No registration required in most places
-Good way to learn about motors, good way to learn about modding, without breaking the bank
 
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Steve Best

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Sep 22, 2012
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For me there are 2 reasons
1) I love the lightness and simplicity compared to my motorcycles.
2) It is a wonderful platform to experiment and learn about 2 stroke engines.
 

FurryOnTheInside

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Sep 23, 2013
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I already know something about bicycles. I'm only just beginning my learning about engines. It doesn't matter so much if the engine stops working, because a bicycle has pedals that really work. Not like a moped where the pedals aren't really practical, or a powered hang glider where engine failure would be really bad news.
 

Steve Best

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Sep 22, 2012
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Actually, I had a hang glider for several years.
They actually work quite well without a motor as long as you are ok with what is beneath you!
You think motorized biking is dangerous? Try teaching yourself to fly with a 1980s hang-glider.
Bruises aplenty!

Seriously Matt, put the engine together as designed, really, NO modifications.
It will work. Pay attention to:
1) Buy a 1/4" torque wrench and always use it on all the fasteners.
2) Get the rear sprocket true and aligned with the front chain sprocket.
3) Get the chain tensioner SECURE on the stay, so it won't slip into the spokes.
4) Slight slack in the chain.
5) Regularly (every ride? weekly?) check the bike over for loose bolts (go to #1) and problems.

This will teach you what it is to be a good mechanic.

Now, take the opportunity to try modifying things, ONE ITEM AT A TIME!
I'd suggest learn about plug reading and jetting first.
Then maybe learn about squish, setting it up, and maybe modifying the head.
Then maybe try your hand at porting, a little at a time, not too much at once.
Learn to test for acceleration on a vacant spot, or top speed up a hill.
See if you are improving anything with your mods.

Lots of guys mod a dozen things at once and don't really improve anything.
Much of their mods are just trying to make up for their poor mechanical skills.
Mod one thing, then test if it is an improvement.
 

FurryOnTheInside

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Sep 23, 2013
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........

Seriously Matt, put the engine together as designed, really, NO modifications.
.......
Each to their own I guess but I had to make changes to the engine kit to some extent just to put it together.

Ungraded bolts and cross threaded nuts, squashed flat cables, deeply scored head mating surfaces, flaked cylinder lining, mounts that don't fit the bike, dry bearings, uncomfortable and too short grips, no waterproofing on the electrics, clutch lever that won't fit under a brake lever, hard PVC fuel pipe... Correcting these things won't make it run worse.
 

gary55

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Nov 27, 2012
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Steve is probably right on staying stock to begin with. He is surely right on the over modifications some do cause I am one of those some. I listened to all the different mods. people were doing and did them all at once. this left me not knowing which ones were effective or not. While the engine has more power than stock the latest engine I built for myself has half the mods. of previous builds and runs better. I'm sure he didn't mean to just slap it in the bike right out of the box. You should disassemble and inspect the parts for imperfections in port window castings and welds in the intake so no pieces break of when started and damage the engine.View media item 60327View media item 60326
 

Steve Best

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Sep 22, 2012
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Good points Furry, and I guess I see many of these things as normal mechanical skills.
The bolts on the 4 engines (even the 2013) I have all have sufficient fasteners. Not great, but sufficient.
You bust them, strip them or cross thread them is operator error. So torque them and run it for now.
A novice is likely to cause more damage by upgrading the hardware with all the disassembly needed and no torque wrench. We have seen it!

Squished cables do happen, certainly obvious defects need to be addressed.
I've had cylinder defects and rough head surfaces but none have affected operation.
Again, having a novice tear into this has a greater likelihood of damage than what they intend to cure.

All modern bearings come with very little lube on them, often just an oil coating.
Read the instructions and lube as needed, that includes the reduction gears. Normal maintenance, in the manual.

So what can go wrong with your suggestion of replacing the hardware and cables, pulling the head and cylinder for checks, replacing lines and grips, lubing and waterproofing everything? Stripped threads and cracked parts, impossibly wrong length and damaged cables, multiple trips or delays to shops or on-line trying to get new or better parts, damaged parts, wrong alignments, wrong lubricants, too much lubricant, slipping clutches, leaking seals from operator damage, endless delays and frustrations from problems and "imperfection". This often leads to parts lost or kits abandoned (Yay! I get a great deal!)
Install it as instructed and you are running in an afternoon, running and learning.

Furry, you have better than average mechanical skills and experience, and great knowledge and expectations about bicycles in general. You are not the target audience. If you are new to mechanics and to these engines, I stand by my advice to assemble as instructed an resist the urge to modify. With a novice it introduces more problems than solves. I back this advice with 40 years of well educated experience in industry. The first thing we do with unreliable machinery is put it to the "as designed" state, and start solving problems from there. I recommend the same thing with these engines.

This is the beauty of these engines. Put it together as designed, knowing it will work well as designed if you do your mechanics well. Then, work on things one at a time, learning and improving.
 
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