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Author Topic: '73 CB350F - Removing goo from cylinder  (Read 523 times)

Offline tahitianrider

  • Posts: 110
    • tomracingdesigns.com
'73 CB350F - Removing goo from cylinder
« on: Nov 25, 2018, 13:29:26 »
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 n4 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 n4 so it will blow the things outs from there?

I do not have electricty in my garage so compressed air is not an option :(
'94 BMW K75 Racer
'84 Yamaha XJ 600 "Rocket" Racer
'76 CB 360 old school cafe
'96 CM 125 Brat bike
'80 CX 500 Racer
'73 CB350F Scrambler
'77 CB750F2
'70 CZ 125 vintage 2 stroke!
www.tomracingdesigns.com

Offline cxman

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  • Posts: 2730
Re: '73 CB350F - Removing goo from cylinder
« Reply #1 on: Nov 25, 2018, 14:04:15 »
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
1978 CX650 Super Deluxe
1979 XS1100 Special
1974 xl350
1983 cx650 Custom
1973 cb750
1980 cb750
1981 cb650
1982 cb900 c
1974 kawasaki 350 bighorn
1983 GL1100 aspy full dress
1983 GL1100 Nekid
and a bunch of others

Offline tahitianrider

  • Posts: 110
    • tomracingdesigns.com
Re: '73 CB350F - Removing goo from cylinder
« Reply #2 on: Nov 25, 2018, 14:26:43 »
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 ! :)
'94 BMW K75 Racer
'84 Yamaha XJ 600 "Rocket" Racer
'76 CB 360 old school cafe
'96 CM 125 Brat bike
'80 CX 500 Racer
'73 CB350F Scrambler
'77 CB750F2
'70 CZ 125 vintage 2 stroke!
www.tomracingdesigns.com

Offline tahitianrider

  • Posts: 110
    • tomracingdesigns.com
Re: '73 CB350F - Removing goo from cylinder
« Reply #3 on: Nov 25, 2018, 14:35:32 »
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 ?
'94 BMW K75 Racer
'84 Yamaha XJ 600 "Rocket" Racer
'76 CB 360 old school cafe
'96 CM 125 Brat bike
'80 CX 500 Racer
'73 CB350F Scrambler
'77 CB750F2
'70 CZ 125 vintage 2 stroke!
www.tomracingdesigns.com

Offline cxman

  • DTT SUPPORTER
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  • Posts: 2730
Re: '73 CB350F - Removing goo from cylinder
« Reply #4 on: Nov 25, 2018, 16:56:44 »
i would run it a bit then store the thing with some marvel mystery oil in the cylinders
1978 CX650 Super Deluxe
1979 XS1100 Special
1974 xl350
1983 cx650 Custom
1973 cb750
1980 cb750
1981 cb650
1982 cb900 c
1974 kawasaki 350 bighorn
1983 GL1100 aspy full dress
1983 GL1100 Nekid
and a bunch of others

Offline tahitianrider

  • Posts: 110
    • tomracingdesigns.com
Re: '73 CB350F - Removing goo from cylinder
« Reply #5 on: Nov 26, 2018, 04:47:08 »
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
'94 BMW K75 Racer
'84 Yamaha XJ 600 "Rocket" Racer
'76 CB 360 old school cafe
'96 CM 125 Brat bike
'80 CX 500 Racer
'73 CB350F Scrambler
'77 CB750F2
'70 CZ 125 vintage 2 stroke!
www.tomracingdesigns.com

Offline cxman

  • DTT SUPPORTER
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  • Posts: 2730
Re: '73 CB350F - Removing goo from cylinder
« Reply #6 on: Nov 26, 2018, 07:51:03 »
that should do it

spray rotate the motor spray some more after you fog it
1978 CX650 Super Deluxe
1979 XS1100 Special
1974 xl350
1983 cx650 Custom
1973 cb750
1980 cb750
1981 cb650
1982 cb900 c
1974 kawasaki 350 bighorn
1983 GL1100 aspy full dress
1983 GL1100 Nekid
and a bunch of others

Offline tahitianrider

  • Posts: 110
    • tomracingdesigns.com
Re: '73 CB350F - Removing goo from cylinder
« Reply #7 on: Nov 28, 2018, 15:30:21 »
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 :)
'94 BMW K75 Racer
'84 Yamaha XJ 600 "Rocket" Racer
'76 CB 360 old school cafe
'96 CM 125 Brat bike
'80 CX 500 Racer
'73 CB350F Scrambler
'77 CB750F2
'70 CZ 125 vintage 2 stroke!
www.tomracingdesigns.com