Furthering my education - what the #@%$ are all those tubes coming out of the Carby for?

[Bartz]

So I just posed this question to a lady at work and she had no idea either ; she suggested Google but I know a better place!

So air goes in through the airbox and fuel goes in from the tank, some magic happens and the waste goes out the exhaust right????

So what are these 5 or 6 daggy tubes coming out of the carby and draining beneath the bike actually doing? I saw in my googling a filter you can get for these tubes, so are they also sucking stuff into the carby? If so why does one want to suck stuff from beneath the bike close to mud and dirt and water?

Are the Italians just being crazy again?

 

[huskylove]

they are vent/overflow tubes. Most mx bikes have these. When your bike tilts over, the fuel float gets stuck in the open position so the carb fills up with fuel and it comes out specified vents/drains down and out the tubies.

 

[Bartz]

Ah see I have learned yet another thing, cheers!

 

[robertaccio]

PS its a Japanese carbbby. Vents to atmosphere, air pressure on top of float bowl fuel must be same as ambient, also as mentioned above to vent out fuel overflow, also to displace air as fuel comes in. Those little vent filters that are sold by 7602 racing are good idea that work at keeping dust from getting up in there. There is alot of vacuum in and around the carb. Ive found lots of dust on top of the slide on many service occaisions.

 

[Colo moto]

The line coming off the bottom of the float bowl is the float bowl drain/overflow line. It is open to atmosphere at all times via the little brass tube on the inside of the float bowl. There is also a secondary opening at the bottom of the bowl that you can open manually via a flat head screw to drain the float bowl. Like in the case of suspected water in the bowl.

The other 4 lines coming off the top of the carb connect to 2 passageways that enter the roof of the float bowl chamber. These 4 lines allow the pressure in the float bowl to equalize. When you are hammering over bumps and jumps the gas is sloshing around in the bowl along with the air. There are 4 vents to ensure that hopefully at least 1 remains open should the others become plugged up with mud or debris. They exit the bottom of the motorcycle in the dirty air mostly because of liability concerns. When you take a digger gas runs out those lines and the lawyers want that gas pouring out far away from hot engine parts and exhaust systems.

We do make a filter for the 4 lines that does an excellent job of filtering out the dust and dirt that can make it's way into the float bowl. We should have more filters in stock soon.

http://7602racing.com/prod_t6cf.php

 

[robertaccio]

this is one way of doing the above 7602 carb filter assy. 2008 TXC450 reference.

 

[Colo moto]

I like how your bikes always look like they just finished a race.... or a war.

 

[robertaccio]

I like how your bikes always look like they just finished a race.... or a war.

I think this was immediatly after the AMA Western HS event at Anza, judging by the yellow plate 117H, but may be post AMA Nat H&H, because I left the WHS set up in place thinking I would race more in that series.