improving performance

What is the least expensive way to improve the performance of a v twin
motorcycle. I own a Vulcan 900, which has a top speed of 105 mph. I am
not sure why is so slow at the top end. I have considered changing
pipes, changing the air intake system, getting a commander that will
change the timing of the fuel injection, or changing pulleys in increase
top speed, but would lose acceleration.

 

Because it's not a high-performance engine for starters.

It's the old saying - "speed costs money, how fast do you want to
spend?"

Playing with the exhaust and air intake, plus tweaking the FI may make a
noticeable difference, but $deity only knows if it's worth the cash.

 

Adjusting the stock camshaft timing. This is called "degreeing the
cams".

You will lose a little "low end torque" and gain more top end
*horsepower*.

I own a Vulcan 900, which has a top speed of 105 mph. I am

I recommend that you find a web-based site dedicated to Vulcans and
*carefully* read what the knowledgeable-sounding owners have to say.

I don't know the details of your machine, but it's possible that your
engine has a RPM limiter to stop it from revving any higher than it
does, or if the cam shafts are set up to have zero overlap to meet EPA
rules.

If you can find out what the cam timing specifications are, you might
be able to get a little more power out of the engine by retarding the
exhaust cams and advancing the intake cams a few degrees to raise the
power peak.

This is usually done by removing the camshafts, unbolting the
sprockets, and filing the bolt holes oval so you can move the
sprockets in relation to the camshafts.

 

Sell it and buy a cheaper faster bike. Seriously.

 

Exactly. Why do people buy bikes that aren't designed to go fast
and spend lots of money to get them to do it, when there are bikes
made with _very similar designs_ that will go much faster, for about
the same money? And if performance was your object to begin with,
why not buy a bike that goes fast, is comfortable (assuming someone
who buys a Vulcan doesn't want a "crotch rocket") and handles
quite well, too?

Not that there is anything at all wrong with a Vulcan 900, a nice
bike if you like that sort of bike, and a 105 mph top speed is
certainly adequate for normal usage everywhere except the Autobahn
or Autostrada.

 

What do you want to do? Go way past 105 or be fast on your take off.
If it is going way past 105, gear up with sprocket changes and put an
egg shaped faring on the bike you can hide behind. Frontal area air
resistance is your enemy. If you want to take off fast also, than you
need a tranny with more gears and the right ratios. 900 cc should be
enough power to take you past 200mph with an aerodinamically correct bike.

 

And the A21 on my way to work...

....oops. What a giveaway.

 

Lying flat down on the bike wearing nothing but a pair of trunks.

http://en.wikipedia.org/wiki/Image:Rollie_Free,_record_run.jpg

Very inexpensive.

 

UKRM anecdotal reports of lucky escapes/flagrant hoonery notwithstanding,
is it not true that if you are nicked at over 100 mph in the UK you are
facing a likely ban, just as you are in my home state?

http://www.drivingban.co.uk/driving...n_100_mph_on_the_motorway._Is_a_ban_automatic

http://www.house.leg.state.mn.us/hrd/issinfo/ssspdlt.htm#Q4

Still grinning over the memory of darsy and adie's videotaped antics w/
plod commentary.

 

And the rear fender looks mandatory.

 

It's likely, yes. Not a certainty, but likely. That's assuming 100mph in
a 70mph zone, of course. If you're up for 100 in a 60, let alone lower,
a ban is a near-certainty.


To counterbalance this, many TrafPol (especially bike Plod) will
actually put on the ticket that you were doing (say) 98mph instead of (a
true) 100+, as long as you were riding fast in a safe manner and not
being a ****.

This is because they know that speed in itself isn't dangerous and that
a ban would be unfair. I've escaped a ban once because of that, and a
certain speeding penalty on another two occasions[1].

Seriously, bike Plod tend to be very lenient - as long as you're not
being a....

[1] One of these involved a friend and myself doing 100+ speeds in a 60
limit, early one sunny Sunday morning.[2]
[2] And was the inspiration for my TOG tag. In the eyes of the bike cop
who eventually caught up with us, I was "an older gentleman who should
know better. Now off you go."

 

Have you seen that that very bike is up for auction?

 

LOL!

 

I really don't want to look at it or think about it or find
out how to bid on it.

 

Look no farther. If you have PULLEYS, that's your problem !! ;-)

Seriously, if you really think you need to go faster than 105......on a
cruiser, no less......then SELL IT AND BUY SOMETHING WITH MORE POWER.

Or pour a shit load of money and time into it, only to find that <gasp> it
will never be a race bike.

IOW, get serious.

 

Heh. A very sensible reaction, sir. I understand Lawrence of Arabia's
Brough is also extant.

 

Castration helps the aerodynamic too. After all bulges slow you down