'73 CB350F - Removing goo from cylinder

tahitianrider

New Member
Hey!

I picked up a 1973 CB350F last week with 20000 original kilometers, the bike has been sitting for at least 20 years, previous owner did not even know the last time the bike ran. I found some clue about probably an oil change a 13000km in 1989, but not sure.

Anyway, before rebuilding this beauty, I wanted to restart the engine which wasn't seized. My only concern was some kind of "goo", or kind of carbon mud inside the cylinders. I guess some humidity might have came in and it created this. Some cylinder had more than other.

What I did so far was change the oil, pulled out and ultrasonic cleaned and rebuilt the carbs, and I also changed the points and condenser and checked the static ignition timing, which was good! I was pretty surprised!

So I tried to start the bike hoping the residues inside the cylinders that were moving freely would burn off. The bike started pretty easily!
I ran it for about 2 minutes. Ton and tons of smoke coming out!! it was crazy.

After that, I noticed that cylinders 1 2 and 3 ran pretty great and burnt off most of the deposits and residues inside.
The exhaust on the cylidner 4 however was pretty cool, so it barely ran, I noticed that the problem was that the goo on this cylinder blocked the spark plug so preventing the spark.

My question is:

Is there anyway I could clean the cylinder n°4 from the spark plug hole without having to tear the engine appart??
I though maybe spraying some carb cleaner trhough there... or maybe even ignite it from the plug hole lol
Or maybe start the bike without the plug on cylinder n°4 so it will blow the things outs from there?

I do not have electricty in my garage so compressed air is not an option :(
 

cxman

Active Member
DTT SUPPORTER
clean the plug and restart it

if you wash the cylinder down then you leave the walls dry it can damage the rings

clean the plug and see if it will burn off like the rest try it a couple of times and see if it works
 

tahitianrider

New Member
Ok I will just try to clean the plug and run it over and over again, good thing is I have 3 or 4 more plugs so I will be able to quickly swap and restart, thanks ! :)
 

tahitianrider

New Member
And after that should I use some cleaning additive like seafoam or basic fuel additive to clean up the combustion chamber or those don't really help ?
 

cxman

Active Member
DTT SUPPORTER
i would run it a bit then store the thing with some marvel mystery oil in the cylinders
 

tahitianrider

New Member
Ok thanks, that's great because I won't run the engine during the rebuilt so 2 or 3 months anyway.
I can't find any marvel mystery oil here in France, but do you think this would do the job ?
https://www.opieoils.co.uk/p-92354-motul-fogging-oil-long-lasting-corrosion-protector.aspx

Motul fogging oil
 

cxman

Active Member
DTT SUPPORTER
that should do it

spray rotate the motor spray some more after you fog it
 

tahitianrider

New Member
Finally got cylinder 4 to run, had to clean the plug several, but the main issue was actually a broken carb intake manifold.

I will now run the bike few more time and store it with fogging oil :)
 
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