'79 CB650 carb jetting

The carbs were bloody awful on the CB650.

 

Hard starting due to lack of ignition system voltage was a problem for
motorcycles back in the 1970's, so riders learned they had to set
their idle mixtures fairly rich to get the bike to start.

But the ignition system voltage was so low they still had to gap their
spark plugs down to 0.025".

With a gap that tight, it was a hit or miss proposition as to whether
any burnable mixture would be near the gap when the spark jumped.

The solution in those days was to fit K-Mart ignition coils to
Japanese motorcycles.

They put out 35,000 volts and would make an inch long spark in free
air.

The K-Mart coils cost only $6.66 and the extra voltage made it
possible to open the spark plug gap to 0.035", making the engine
easier to start.

The Chevy HEI system you mentioned will make it possible for you to
open your spark plug gap so the weak mixture will find the fire...

 

You always wanted me to be your daddy, didn't you?

C'mon, 'fess up.

Everybody knows it...

 

This is total, utter, complete, hallmarked, attested, certified and
triple-plated nonsense.

Not only did I, and everyone I knew back then, *never* have a problem
starting any of the many machines we owned in the 1970s[1], but I even
have a 1970s machine today, running a completely stock 1970s ignition
system, and it starts perfectly. Every time.

You know nothing.

[1] Well, Steve with his Triumph TR6R had some moments...

 

You never even knew there was a *problem* or what the engineering
solutions were, fool.

 

This bike starts O.K. It just takes six miles of riding to get to where you
don't need to choke it. It is a pain since the first intersection I hit is
on a highway 1/2 mile up the road and it wants to die at the stop sign
unless I add more choke.

What about this K-mart coil? Do you think I can still get one?

I also have a 1971 CB350 that runs great -- only needs choking to start up
when cold then I shut the choke right off and go -- the same with a 1971
CB450 I once had.

 

There was no problem.

Sure, some bikes can be buggers to start - I remember by SR500 single
definitely needed the 'knack' (but once acquired, it was a first, or at
worst second, kick starter).

You're saying that 1970s Jap bikes were hard to start, which is your
usual bullshit.

Keep dancing.

 

I haven't seen ignition tune up parts and coils at K-Mart for many
years, but I'm sure you can use almost *any* automotive coil that was
designed with ignition contact point systems in mind.

In order to rev small displacement engines to high RPM which requires
the magnetic field in a coil to break down rapidly the Japanese
engineers accepted a voltage compromise.

The smaller, lower inductance coils only put out about 9,000 to 12,000
volts maximum.

There is a property of coils which is called "inductance."

As each turn of copper wire in a coil is energized, it causes a
counter-electromotive force which opposes the energization of the next
turn.

So, having smaller coils with less iron inside made it possible for
the coil to charge and discharge more rapidly.

Unfortunately, that discharge time still wasn't fast enough to avoid
the high voltage from bleeding off across the carbon on the nose of
the spark plug.

Electronic ignition systems are able to make and break the primary
circuit more rapidly than a set of ignition points can.

Also, the high current through a set of contact points rapidly burns
and erodes
ignition points.

Motorcycle enthusiasts who installed K-Mart coils would often install
a 6-volt coil with a ballast resistor which used full 12 volts during
start up, then the resistor would heat up and drop the voltage back to
6 volts.

I bought a solid state electronic "ignition amplifier" to reduce
current through the points by using a switching transistor.

 

How would *you* know?

You weren't riding motorcycles, you were giving blowjobs to the senior
boys at boarding school in the 1970's.

 

Krusty gets it wrong *again*. You need to work on your stalking. Got my
first bike in 1976, the year I went to university.

And, sweetie-pie, I've owned more bikes than you could possibly dream
of, 1970s and later )

Keep dancing.

 

Krusty gets it right at last. Monkeys, Hamlet, typewriters, etc.

 

no I've always wanted an excuse to end you existence...

Oh btw in case you didn't know. Your advice is dead wrong...it's the
idle jets. You stupid pedophile.

 

No shit.

 

Nope I shit you not you perscription drug abusing child molester. Your
advice was as always dead fucking wrong.

I do hope some nice californians hang you with your entrails...while
you are still living.

 

I know. A turd was the first friend you ever had, and you cried when
Mommy took the potty away...

 

You know child rapists like you are the most hated people in the world
and that's before anyone finds out the kind of scum you are. Then,
they start drawing straws to see who gets to kill you...

I hear you've got time, it's a large pool and many people haven't
drawn a straw yet.

 

You should get a job in a movie theater, you're always projecting.

 

lol and now you qoute me, you insane alzheimers addled fraud.