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The
Bullet: Mysteries & Myths -
Don't just love but get to know your
bullet more - by B. R. Gurunandan
Improve Your Bullet! (Life,
Safety, Performance, looks)
As a rule of nature, all creatures come into this
world semi-functional, helpless, and ignorant (many
of them remain that way, but that is another story)
and are brought up into magnificient, able and wise
beings by their doting and forgiving parents or guardians.
In that respect, our Bullets are "close to nature".
They are manufactured with built-in shortcomings and
design-flaws. So you, the owner, can develop a stronger
bond with it as you labour to overcome them and "bring
up" your Bullet the way you want it to be. Maybe I'm
wrong. It may be that the company was following the
dictat of our erstwhile socialist govts, and "creating
jobs" for the lakhs of mechanics, machinists and replacement-parts
industries.
Well, that WAS our customary rewind. Now fast-forward
to tech.
This time we list the problems we have often encountered
with our new Bullets, and start discussing the ways
to overcome them. But, sorry Newbies, don't reach
for your spanners just yet, this is just another "high-level
document"; we shall get to nitty-gritty practicalities
when I get hold of a digital-camera or AutoCAD or
something.
Noisy Engine
Let us take the manufacturer at face value, and believe
the yarn about tightly maintained tolerances due to
upgrade to CNC, etc. So there is no noise from valve-guides,
rockers, tappet-guides, piston/crank pins, etc. But,
please, no one tell me that spur-gears can be tossed
on to fixed spindles with ZERO backlash and no galling
either. And somebody tell the manufacturer that CNC
is not a remedy for all the sorrows of mankind. That
it stands for Computerised Numerical Control, not
Con N Cheat.
So that is the prime cause of noise in a new Bullet
engine: Backlash in the valve-train gears. The solution
is as simple as replacing the original fixed camgear-spindles
with adjustable ones and making the backlash zero.
But a word of caution. This has to be done in the
very early days of the life of the engine, before
the cam-gear teeth lose their profile from repeated
impact due to lash. Once the gear-flanks have collapsed,
they cannot be adjusted for zero backlash without
galling the other teeth. So the cam-gears have to
be replaced if you have used the bike a lot before
installing the adjustable spindles.
Beware of this sucker-punch:
Some shops offer to reduce the cam-noise for a temptingly
low amount. How do they do it? They do not change
the spindles. They measure the lash with a feeler-gauge,
and make new eccentric bushes to give zero lash at
the time the cam-nose is passing the tappet. Naturally,
the lash is plenty increased at other times. The bushes
wear fast from this punishment, and soon you are worse
off than when you started. OK if you want to sell
the bike to a skunk.
Lubrication check
A real Bulleteer does not rely on the warranty. He
knows fully well the tendency of the Indian dealers
to wash off their hands once they have pocketted the
money. So it makes sense to check that the lubrication
is OK, because if there is a blockage at some point,
extensive damage will occur, which the dealer will
NOT rectify without a prolonged lawsuit!
It is not difficult to spot blockages.
You have to remove the tank (place it on the seat,
etc, and connect the fuel-hose) and the rocker-covers.
Then start the engine. Within a minute, you will see
oil spurting from two slots on each rocker-block.
Oil is being spilled on the pushrod-cups and on the
valve-stem ends. Often it so happens that the four
flows are of unequal volume. Increase the RPM and
note where the oil-spurts land. If they are almost
equal and landing in the right places, all is well.
This tests the pumps, filter and lubrication of crankshaft
as well, because they are "in series".
If the four spurts are of drastically different volume,
or there is very little oil flow even after a long
time, something is wrong! You might prefer to get
it rectified by the dealer or mechanic if you are
new to this, but it is not difficult.
Sitting-ducks
The Battery sits there, fastened by a single screw,
inviting every passing paki-tramp to launch into a
career of crime. The "accessory" industries have goofed-up
on this one. You see a lot of add-ons, but they are
worthless from the security point of view, being either
insufficient (also single screw fitting, or generic-key)
or impractical (needing a rattly padlock!)
And the original bracket is also of a very thin gauge
of steel-sheet, which, to the acid-leaks is like blotting-paper
to rain.
Both these glitches can be corrected by a hefty, powder-coated
bracket that uses a couple of Allen-headed fastners
at the back, making it very, very difficult to dismantle.
The same idea can be used to secure the headlamp,
carb(flanged type), and any other tempting fittings
that you may be paranoid about. Amateur thieves use
a coin or pen-knife as screwdriver and carry a few
sundry skeleton-keys; Allen-key set is a bit out of
their league.
Well, there is a slightly better way also, but it
would be self-defeating to explain it here. It can
be e-mailed to "registered users" maybe, so making
it a better kept secret, and hence more effective.
So take the trouble of "registering" with a response
to this, with an unwritten gentlemans' agreement not
to divulge it on public any forum.
Vehicle-lock and..
When you park the bike in a "hostile" place, you risk
not only the fittings, but also the whole bike itself!
The standard ignition lock is a cheap, generic one
which can be turned by any key or even a small screwdriver-blade.
And if you dont have either of those, a jumper wire
from brown/white to white wire on the back of the
lock will "short" the lock and enable ignition. ALL
potential thieves know this by now. AND the key tends
to fall off on rough roads. Or the rattling chained-key
irritatingly scratches the toolbox paint. What to
do?
Buy a small but STURDY, NON-STANDARD plug and socket
with ATLEAST 4 terminals. Cut the battery wire, the
ignition wire, (etc) and solder the ends to the socket,
the back of which should not be easily dismantlable.
Wire the plug to short the breaks. You can also wire
the socket so shorting a particular combination will
blow the horn. The gist of this is: Make the wiring
non-standard! That by itself will deter many thieves.
They will move over to easier prey. You can keep the
lock turned to "On" position permanently, and pull
out the plug to disable the bike. A good place for
the plug & socket is below the seat. It should be
difficult to reach the wires, and ideally you should
change them to non-standard colours.
Another advantage of this system is, you can wire
another plug to a charger, which can be plugged to
the bike in a jiffy without messing with crocodile-clips
at the battery-terminals.
Running without the Battery
You don't have to have a battery stolen to experience
this one: The frustration of trying to run a Bullet
without the battery. The manual tells you glibly to
turn the ignition-key anti-clock-wise and go on even
if your battery is kaput. But try running a Bullet
with a flat battery or one on its last legs; it is
guaranteed to make you swear. Major-ly. Royal-ly.
Briefly, when you turn the key anticlockwise, the
ignition coil goes into the charging circuit and the
ignition takes place off the alternator, not battery.
The alternator produces pulses of current when the
magnet passes by the coil, not a continuous current.
You will see that the magnet is positively located
on the crankshaft by a woodruff-key, so the pulses
are intended to be produced at a particular position
of the crankshaft, and hence the piston. Great!
A hint - do this small test first: With the key in
the "emergency" position, kicking the engine should
swing the ammeter momentarily into the green. If it
doesn't move, use a jumper-wire to earth the wire
going to the non-earthed terminal of the battery (after
you remove it from the battery). Now the battery is
bypassed, and it's condition or presence is immaterial.
The engine will start smartly. But...try to rev, and
the engine stutters and falters. Why? ...And you thought
this was a simple, newbie serial! Hahaha! The answer
was in Pt3!!! Yes, the "advance mechanism" alters
the ignition timing as the speed increases, and the
pulses from the alternator no longer are in sync with
the contact-breaker!
Hellsbells! So all this is just to limp home swearing
instead of standing on the road swearing, eh? Well,
not if you are prepared to spend about Rs100 (USD
2.oo). What you do is substitute the jumper with a
10,000 microfarad condenser rated 65V.
What does it do?
It "stores the pulse" from the alternator, and the
coil can use it "later".
Why 10,000 microfarad?
Standard value, marginal cost increase over 2000 or
5000 microfarad, which also work but MAY not be as
effective as 10,000.
Will 20,000 be better?
Try. I could not see any difference.
Why 65 Volts?
Safety. If the Zener has gone open circuit, the alternator
voltage will reach around this value at speed. Overvoltage
ruptures condensers and spills nasty juices.
So bow to Murphy, don't use 16Volt condensers, though
they are much cheaper.
And remember that these condensers are fussy about
polarity.
Earthing
Try this: Clip the negative lead (positive for positive-earth
circuit) of your multimeter in 3-volt range to the
chassis or battery-terminal, and the positive to handlebar,
or any bolt on the steering-head. Switch on the Headlamp.
Do you see any voltage on the meter? You should not.
But it is common to find upto 0.6Volts. That is 10%
of the 6V battery, 5% if it is 12V! Being wasted!
I do not want to debate the ill-effects of the headlamp
and horn current flowing thru bearings or cables,
just the idea of considerable amounts of power being
wasted is enough to get me into action! This could
also be the reason for horn/light faltering on rough
roads although no wires are having loose contact.
The remedy is simple and FREE! It only needs a thick
copper wire to be bolted, from the steering head to
chassis or battery-earth!
Centrestand
The axle going thru the top tube of the centre-stand
is anchored by two plates bolted to the frame and
casting. Problem is that the plates are very thin,
and negligibly strengthened around the axle. Soon,
the holes become oval, and the bike "rocks" on the
stand. The remedy would have been VERY simple if the
mfr had done it; it will be a bit more painful for
you to do. But the sight of a bike that rocks on the
stand is quite disturbing to most of us, and instead
of just replacing the plates for a temperory relief,
you may as well go the whole hog and repair it for
ever. Like so:
Remove the plates with the bike on props or sidestand.
Dismantle the centrestand. Procure a pair of 1/4inch
thick 1inch dia washers from any hardware store. The
inside dia is not important as long as it is smaller
than the axle-rod dia. Also procure a rod about 3/4
inch longer than the original. Now bolt the plates
together, inside-to-inside thru their mounting holes.
Bolt the washers one on each side, thru the axle-hole.
Weld the washers (one to each plate, from the "outside")
Remove the bolt thru washers, and drill a hole of
dia equal to the rod. Assemble the plates. Measure
the distance between washer faces. Drill two small
holes for splitpins thru new rod and assemble. Why
go to the pain of a new rod, etc? Why not weld the
washers to the inside of the plates? Then you have
to cut/grind off half an inch from the top-tube of
the stand to accomodate the welded washers. Advanced
theory of static-mechanics, or elementary common-sense
tells us that shortening the top-tube increases the
stresses and wear by sideways forces when bike is
on stand. It won't be the plates, but the tube which
distorts if you do this! So don't.
What about using thinner washers, and/or drilling
new holes in old rod? Try.
Levers
You will notice one major difference in the fitting
of old and new clutch/brake lever brackets. The old
ones had two bolts, and split into two pieces which
could be removed easily. The new ones have one bolt,
and have to be slid off the ends of the handlebar.
To change the brake bracket, you have to remove the
throttle-grip; left-grip and switch-assy for clutch
bracket. Imagine doing all this on the road in the
event of a mishap!
For quick-change, you don't have to switch back to
the old steel type. Just try this:
Remove the brackets and cut them into two pieces by
sawing across just ahead of the mirror-boss. In fact,
you don't even have to saw thru fully. Just making
two notches and forcing the brackets open with a pair
of tyre-levers will break them neatly (almost) between
the notches. Now you don't have to slide them back
on. Just open the single bolt and put them on/take
them off within a minute! Don't worry, one bolt is
quite sufficient to hold the pieces together just
as firmly as the original. If your spare has been
treated similarly, you can change the bracket with
a single spanner within 10 minutes instead of spending
an hour and many curses.
There is a further useful modification to the levers
itself, that was suggested by Mr Roger Ward at REBEL
list, but that requires a diagram to understand and
copy. Sometime in the future.
Main Page
Starting a Bullet - Part 1
Starting a Bullet - Part 2
Starting a Bullet - Part 3
Running-in a new Bullet
Info for Bullet maintainence
- Part 1
Info for Bullet maintainence
- Part 2
Improve your Bullet
Newbie Exercise
Bullet-Trivia
Cam-Gear Backlash
Diagnostic Tests
By B. R.
Gurunandan
Nandan is an engineer, with , Bangalore
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