Motorcycle Repair: Yamaha, question thanks, nice bike

Question
QUESTION: Hi Wayne,

In 1973 I bought a beautiful blue 1973 125cc Yamaha.
The paperwork says it's model A T38LU, 13.0 hp.
I bought it to ride thru the woods and it probably
has less than 200 miles on it ... and it's been
sitting for 38 years, still in it's beautiful
condition.  My husband drained the gas tank
but I think that's all.  Years ago he told
me the engine was frozen from sitting.
Husband is gone, but I still have my bike
and wonder what this frozen engine means.
What do you think it needs for this condition
and what should I do about it?  I'm thinking of
selling it but it needs to run first.  I don't
know what I should ask for it, either, do you?
Thank you for your help.

~Candy

ANSWER: Hi Candy,

Nice bike, I used to work for yamaha and repaired many of these.
The term "frozen engine" is used to describe an engine which
Is stuck due to either rust and corrosion or seized up from lack of oil

This is usually the top part of the engine where the piston and rings
reside. The top of the engine has to be removed in most cases
and the piston replaced along with honing the cylinder
or reboring the cylinder if very damaged.

The bottom part of the engine may be okay and can be oiled
And reused if okay.

The rebuild depends on who does it.
Parts may only be about $100
but labor is high.

It is not super difficult but must be done carefully.
The oil pump should be checked too and carburetor
cleaned very well.

In running'condition it should bring about
$1500-$2000

Lesser bikes range about $500-$800

They are excellent bikes so it is worth fiximg up.

Let me know if you need more details.

WS
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---------- FOLLOW-UP ----------

QUESTION: Thanks for the quick reply and info, Wayne. I'm wondering
why it would need so much work when it has only 200 or less
miles on it.  It's been stored for 38 yrs in a basement
which had a dehumidifier going (my husband also had lots
of guns so it was always dry there).  I'm only going by
what he told me, that the engine was frozen.  It was like
brand new when I shut if off the last time (38 yrs ago!).
Who would look at and repair this?  Thanks again!

Candy

Answer
Hi Candy,

Tha amount of work it needs depends on how much damage was done
or is done trying to "unfreeze" or "unstick" the engine.

A bike like that should be almost new in every respect except
that after so many years it is possible for seals and gaskets to dry
out and if your husband was correct then the engine is not able
to turn or rotate.

Sometimes if the damage is not great a bit of MMO or Marvel Mystery Oil
I believe it is called can be put into the spark plug hole and
let it sit for a day or two to see if the engine or piston will unfreeze itself.

If you can get the engine to rotate then you would still need to clean the carb
as corrosion and gum from the old fuel in the carb will clog it up.

Clean fuel system, unstick the engine and check all the oil levels.
The battery is also going to be sulphated and dead after so long.
Time does some damage which will have to be addressed before
the bike will be back to it's former glory even though it was nearly new.

Many shops will only work on bikes ten years old or less due to
lack of knowledge and lack of parts for repairs.

Most parts can still be dug up online somewhere but
you need a shop manual also available online I believe and
someone will some average mechanic skills.

If you can find someone local that knows two stroke engines
they may be able to help you a bit.
Even some mower and chainsaw guys might be okay in a pinch.

Try your local bike shops and ask around if there are any vintage
bike enthusiasts. They love to tinker with older bikes.

Let me know if I can help further, very interested in seeing this
old bike on the road again.


WS
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