QuestionI own a 1983 Honda VT 750. The bike has approx. 33,000 km. on it and is in fairly decent shape. I bought it used about 4 years ago and the former owner let me know at that time that it could be difficult to start when cold. When attempting to start the bike I don't turn the throttle, just put the manual choke at approx. 1/3. Unfortunately, the engine turns over repeatedly without any sign that it's going to start. I press the electric start in 10 second intervals. I have pulled the plugs and I know the cylinders are getting fuel. Once the engine does start (most times with the help of a battery charger)it runs well and doesn't miss even at highway speeds. It would seem obvious that this is an electrical problem but what? Do coils become weaker with age? If so, is there a method of testing them? Is there perhaps another component in the electrical or fuel systems that I should be evaluating? Thanks for your help.
Answer
Hi Dave,
There are many things that can combine
to cause starting problems.
The VT750 has a minimal charging system
at best, this means if you are
not driving highway speeds for some time
the battery slowly drains itself.
Keeping a battery tender on it
when parked will help offset this
design problem.
Using new or heavier gauge battery
cables might help as will
a starter clean up or rebuild.
The starters get dirty and corroded
after so many years of use.
Any voltage drop will drain the battery
and eventually the ignition strength suffers as well.
The choke plunger and cables should be
checked and adjusted so they lift
properly.
Check for vacuum/air leaks around the
intake or carb mounts.
The rubber tubes can develop small
cracks which can cause an air leak
instead of the engine drawing the fuel in.
New spark plugs can help even if old
ones look okay.
The bigger and stronger the battery is
the better it will work on these bikes.
They drain the battery quickly
partly due to the low charging rate.
When your battery gets run down the primary coil doesn't
get saturated fully and when it collapses the
secondary doesn't get a full charge so using
a short burst of starting with a few seconds rest
to allow the coils to charge might help.
Sometimes using some good electronic cleaner
like "DeOxit" on the kill switch
and starter switch can aid things.
Also the starter relays and any other related
connections might benefit.
After so many years all the electrical contacts
will have some oxidation.
Using a strong battery and possibly
giving the starter motor
a good clean up might help the most
as long as your choke is functioning well.
Don't depend on the charging system
to keep your battery full, it will
almost always weaken over time
unless you do alot of highway driving.
Many bikes have weak alternators
due to the weight and heat issues
of adding larger charging coils
and rotors.
Good luck!
Wayne S.
--------------------------------------------
