Sprockets & Torque & Cruising Speed & MPG & Chains

 

I could use a brief refresher course on changing sprockets on a
motorcycle.  With a dual purpose bike I once had, when going off-road,
I simply lengthened the chain and hung it around a larger rear
sprocket.  Guess I had a "dual" sprocket on the back of that bike.

On the TW200 I thinking of buying, I understand it comes with a stock
14 front sprocket  and a stock 50 or 52 rear.  And since I've clearly
stated many times that its use will primarily be ON-ROAD, I intend to
switch out the tires to the TW203 and TW204 plus perhaps some sprocket
changes.

1--What will be the performance results of changing the front to a 15
or even a 12?

2--What will be the performance results of changing the rear to a 47
or a 42 or even a 55?

3--By performance results I mean mpg, shift points, higher speed and
quieter engine operation, etc.

4--Is there a publication and/or online source that would provide in-
depth info into sprocket modifications on motorcycles?

Thanx,

Bill

PS--When ordering an aftermarket sprocket, do you need to order a new
chain with it?

 

e:


All the gear ratios and tires sizes for the TW200 are available
online. Look 'em up and plug them into this calculator.

http://www.650ccnd.com/calc.htm


It's best to run new chain on new sprockets.

We discussed the subject of re-gearing the TW200 extensively about a
year ago with a guy who wanted to believe what he wanted to believe,
that he would get phenomenal mileage without performance degradation.

He's still around, with a name change, claiming that installing a
smaller rear sprocket gives him better mileage and that he doesn't
have to downshift for every little hill or headwind...

But, if you study the TW200's gear ratios, you will see that they are
not all equally spaced, they get closer and closer together as you
shift up.

This indicates that the TW200 really doesn't have a lot of surplus
power to allow
gearing it up very much.

I wouldn't recommended raising the overall gearing more than about 3%
or 4% if you don't want to spend a lot of time riding one gear lower
than high gear.

 


Now *there's* a useful link.

Um, that's not the real point. The point is that by messing with the
sprockets he's altering the chain run length.



Exactly.

 



chain with it?


I already realized a different sprocket would require a different
chain length.  On my old trail bike I use to add a small section of
chain when changing to the larger off-road sprocket and pop it out
when reverting back.  My question was more of a "understood" comment
sorta like it's a good idea to change the oil filter when you change
the oil or both wiper blades when one goes bad.  With any project,
it's always best to have all the components start out equally new.

Bill

 

...PS--When ordering an aftermarket sprocket, do you need to order a new

Jesus. Not one master link in a chain, but *two*.

Look, it's a shit idea, so forget it.