Spring-loaded tensioner for $3

This tensioner mod is one of the most elegant I've ever seen!  Simple enough, and I believe this is the only one I've seen that doesn't rely on more than one point on the bike frame.  This is the kind of tensioner that should come with the kits.

Reverse-engineering the Chinese CDI

There have already been discussions on building a superior CDI, but what about the stock Chinese CDI?  While it's rather poor design to begin with, the simplicity and semi-decent functionality make it an attractive electronics project.  I don't think that nearly enough is known about the stock CDI, so I think it's great that this topic has come into discussion.


Rohmell on motorbicycling.com(the same Rohmell who made custom CDIs) created a thread about learning more about the stock CDI and possibly building a new one. 

Scooter windshield on a motorized bike

5-7HEAVEN from motorbicycling.com figured out how to attach a windshield to a motorized bicycle with little or no fabrication or welding!  This could actually improve aerodynamics since the angle of one's body creates a lot of air resistance, but with the windshield air will pass over/around the bike much more easily.

A "fake" oil tank

Well, it's not fake in the sense that it carries oil, but since we are using 2-stroke engines, it doesn't inject oil into the engine. Rather, it's just an onboard oil storage tank, so the oil will be right there when you fill up with fuel.  What a nifty idea!

Homemade tensioner for single-speed conversion

My adventure into the world of motorized bicycles originally started when the derailler and gearing system on my mountain bike fell off and got destroyed.  Since I could no longer practically use the bike for mountain biking or biking around hilly California, I wanted to find a way to bring new life to the bike and avoid tossing it out.  That's how I found out about MBs.


Which brings me to my problem now.  Since I don't have any sort of tensioning, and since my bike frame has a vertical drop-out, converting my bike to just run as a single-speed hasn't worked out so well.  Just the other day, my chain fell off and got gnarled because of my inadequate single-speed conversion.  So since then I've been having to push the bike in order to start it.


What I need is a chain tensioner, but not something ridiculously expensive.  I thought I'd share this thread from mtbr.com about DIY tensioners. 


All I know now is that I'm definitely going to build one of these! 

Clutch lever mod

Wheelbender6 needed some more room for his clutch lever, so he added an extension to mount the lever using an old mountain bike bar-end.  Now that's ingenuity!

Flexi-pipe muffler extension

If you want to extend your stock muffler(or any muffler) to behind your bike without too much expense or welding, that looks like one way to do it!  The post doesn't contain any details as to how exactly it was constructed or how leaks are sealed, though.

UPDATE: The original photo was lost so I replaced it with another one that uses flex tube to have an extended muffler.  Hopefully this will at least help to illustrate the idea behind the original hack.  You can learn more about the muffler extension seen in the photo in this thread.

Break-in secrets

This article on the Mototune USA website describes a somewhat controversial method of breaking in a new engine.  The manuals for our engines always tell us to start out with heavy oil(16:1) and break it in easy.  This idea is increasingly becoming mythical as many people seem to have better results breaking in an engine by using less oil and using less oil.  According to the writer, the most important period in the break-in period is the first 20 miles, and if it's not done right, the piston rings may not seal to their full potential.  I'm assuming I understand this correctly.


Read more about breaking in a new engine "properly"!

Make your 2-stroke sound like a Harley

Hondabicycle from motorbicycling.com claims to have an exhaust mod that will make your 2-stroke engine more like a Harley.  I'm pretty skeptical, but it's a fairly inexpensive mod.  It involves creating an muffler end cap with two baffles and exit holes.  The muffler is also packed with fiberglass.  If anything, this will at least quiet down your bike if it's loud.


This mod could probably be achieved more easily in combination with my washer end cap mod.  Since that has been proven to be an easy and superior end-cap, you could drill two holes in the washer and make your own baffle tubes.  Then just JB Weld them in.  Let that JB Weld set for a long time before use!

EDIT: Let's be clear that I have never actually tried this, so I have not verified if this mod does what it claims to do.