Topic: noob questions about brake fluid and fuel leak

[mightymatt43]

hi all - i'm new to the forum so i'm not sure if yall are used to such simple questions but i could definitely use some direction.

i just purchased a 1976 CB400f with 17K miles. it's not in great shape cosmetically but it seems to run pretty well and i'm looking forward to restoring to the best of my abilities. i'm completely new to working on bikes (which is why i bought the 400 - so i could learn on something) and i've only been riding for 3 years or so. 

the first obstacle i've run into happened tonight. i got home from work and found that there was a sizable puddle of gas underneath the bike. it was dripping pretty heavily out of one of the lines (pictured below) which seems to be attached the first carb (from the left side). i found that i had left the petcock on the run position and as soon as i turned it off, the gas stopped dripping. is this normal and what exactly are the lines?

next, i also realized that there was quite a bit of fluid running down several parts of the front of the bike - the source coming from somewhere in the brake handle. i suppose i first noticed this when i rode it the other day and got some fluid on my right hand. i had to refill the brake fluid reserve when i first got it and its definitely running low again so it must be a constant drip. do i need to replace what i've pointed out with an arrow on the picture below?

thanks in advance for your patience and i look forward to getting to know everybody!

matthew

[scunny]

first your fuel leak, those are the overflows, turn the petcock on again and if it starts leaking tap the carb with the handle of a screwdriver, if the leak stops the float is hanging up. if it doesn't you will have to pull the float bowl to look further. It's a good idea to turn the fuel off anyway.
second, you will probably have to replace the seals for your brake, kits are available

[Mach-5(50)]

my bike (a 550) had exactly the same issues, and they may be normal for their age, if they have been sitting, but otherwise it shouldn't happen.  the gas is from the carb drain tubes. i believe it is from the float being stuck. i am rebuilding mine, after a thorough cleaning. as far as the brake fluid is concerned, it should stay in the reservoir, and again the master most likely needs a rebuild. once you tear into these items, there may be more to tackle, but you can't start without opening them up. also, take care with he brake master. if the fluid leaks onto paint, it will deteriorate it. i am sure there are plenty of threads that discuss these issues in greater depth, so search around. i am certainly not going to have the most technical info, but this is what i have found in my little experience so far. have fun!!! and we all get to learn together.

later,

ryan

[TwoTired]

The tubes you ask about are carb overflows. The carb is only supposed to take what it needs.  If the float valve doesn't shut off the fuel, it over flows.  The tubes keep the gas from going to the stopped engine. seep past the pistons and diluting the oil supply.  It is common practice to shut off the tank valve when the engine isn't running, as a piece of dirt get cause the bowl to overflow.  Check your gas tank for rust, and the gas filter for integrity.

The second  part is you master cylinder leaking.  Probably needs cleaning and a kit for the internal parts.  Be aware that if the brake fluid gets into the bar control, there are plastic pieces inside that get destroyed.  Then you will have starter and headlight problems.

Cheers,