Topic: CB350F finally out of deep storage

[bhh1989]

I inherited this CB350F from in-laws.  From original owner, came with every year's license plate since '74 (until about '90 they didn't have stickers and a new plate was issued every year!).  Original pipes are rust-free, period rear rack and front windshield (stored still).  Knowing I could never sell it, I just stowed it away physically + mentally, saving the slow careful refurbishment work for less busy days.

I will be doing a full sweep of the usual bits - rebuild carburetors 100%, brakes 100%, oil, tires.. all that stuff.  No paint. No buffing. Keep it original - no hacking here.

Question - these pipes are unobtainable in this condition - would it be silly to take them off, store them and ride the bike with some other exhaust?  Do I remember correctly that, even when properly stored and maintained, these pipes WILL begin to rust out from normal use (cold, hot, cold, hot etc)?  I do not want these pipes to get damaged.  Does Carpy still make the 4 into 1?

Look forward to getting this thing totally road-worthy via this forum!

[MauiK3]

Run the pipes, just be sure they are hot and dry after each run, short runs are bad, they never get hot and dry out.

[newday777]

That looks sweet.
The pipes rust from people starting the bikes in cold weather where the pipes are rear cold then the hot exhaust hits the cold metal pipes causing condensation in the pipes and if not going for an hour ride to fully burn off the condensation that is when the rust happens from the inside out. The same thing happens to and exhaust on motor vehicles, unless it's stainless steel.....
If you are going to store the pipes squit in liberal amount of PB Blaster from the head pipes to drip down the pipes as they are hung from the rafters.

[74CB750K4]

Keep it as is with the original pipes and ride the hell out of it, it's an awesome looking original bike.  My '74 750 is practically all original and I got it from my dad who bought it brand new.  He had a '73 350 he sold to buy the 750, would love to track it down, but it's long gone.

[PeWe]

Both my new sets of aftermarket 4-4 to CB750 got a mix of motor oil and naphta to make it thinner and flow easier.
Poured around 2-3 deciliter in each and made sure to cover the entire inside.

Maybe blown away later.  I hope it burned and still cover inside.

There are small holes at the lowest point to let water drip out? Around 2mm.

Mixing oil in fuel will carbonize head, valves w seats and pistons too which is not good.

[Trevor from Warragul]

Okay, how many of the previous respondents have owned a CB350F with a 4 into 4 exhaust system?  I have.  So here's my $0.02 worth.  Many years ago, after working lots of overtime, I saved enough money to buy a 4 into 4 set from Honda.  I only went on long rides, I put 2 stroke oil in the fuel, I coated the interior of the pipes with all sorts of concoctions, and...  the number 1 pipe rusted out at the top, near the end.  The simple fact is an 86cc cylinder cannot generate enough heat to burn off all the moisture in the pipe.  I bought another number 1 pipe, removed the system, and sold it.

If you plan on riding the bike, buy a 4 into 1 (Delkevic make a nice stainless one).

[PeWe]

Where and how bike is stored between rides a factor too.
If parked outside so rain can enter the pipes.

Some of you live in a more tropical climate. High level of humidity with temperature shifts causing condense.

4 pipes have a nice sound

[Trevor from Warragul]

4 pipes have a nice sound

Very true, and they look fantastic too!  However, I'll never forget that feeling in the pit of my stomach when a rust hole appeared in the beautiful chrome...

[bhh1989]

Both my new sets of aftermarket 4-4 to CB750 got a mix of motor oil and naphta to make it thinner and flow easier.
Poured around 2-3 deciliter in each and made sure to cover the entire inside.

Maybe blown away later.  I hope it burned and still cover inside.

There are small holes at the lowest point to let water drip out? Around 2mm.

Mixing oil in fuel will carbonize head, valves w seats and pistons too which is not good.

Yes there are the little holes in the bottom for drainage.  Some rust around the holes on the left side pipes, rights are nearly rust-free.  Naphtha! That's interesting.. I will give that a try.

[bhh1989]

Okay, how many of the previous respondents have owned a CB350F with a 4 into 4 exhaust system?  I have.  So here's my $0.02 worth.  Many years ago, after working lots of overtime, I saved enough money to buy a 4 into 4 set from Honda.  I only went on long rides, I put 2 stroke oil in the fuel, I coated the interior of the pipes with all sorts of concoctions, and...  the number 1 pipe rusted out at the top, near the end.  The simple fact is an 86cc cylinder cannot generate enough heat to burn off all the moisture in the pipe.  I bought another number 1 pipe, removed the system, and sold it.

If you plan on riding the bike, buy a 4 into 1 (Delkevic make a nice stainless one).

That's unfortunate!  See and I will definitely have some short rides around town, not always a long run to help burn things off.  I will look at the Delkevic, I am sure there's a page on jetting for that pipe here somewhere I can dig up.

[PeWe]

I used naphta only to make the oil thinner.
It might be other chemicals to  cover the insides to prevent rust?

[Ryan66]

Nice little bike. My next CB purchase will be a small bore 4 cylinder hopefully. 350 or 400. My vote is clean it up as is and ride the piss out of it!

[Trevor from Warragul]

I am sure there's a page on jetting for that pipe here somewhere I can dig up.

No jetting changes required for a Delkevic.

[bhh1989]

I am sure there's a page on jetting for that pipe here somewhere I can dig up.

No jetting changes required for a Delkevic.

Excellent!!  I was not looking forward to ironing that out.  I already ordered a set.  Great deal on a used set off eBay, less than 500 miles on them.

Began the careful dissection of the carbs, lots of pictures taken.  No real issues other than cleaning varnish.  ChemDip is a life saver, they are coming out super clean.  All the slides were cemented in, requiring slow heat to the carb body and penetrating oil to free them up.  Same with the float pins.

Front brake had no fluid in it at all, thought that was a bit odd.  It appears is may have leaked out the bottom around the piston as the bottom of the caliper had a lot of fluid dust and paint had long ago flaked away.  Is that a thing that happens?

[newday777]

This master cylinder was 33 years in a shed in southern california.

[bhh1989]

This master cylinder was 33 years in a shed in southern california.

MMMM CB couscous!