Carb Overflow Tube

nevernotbusy · Post by **nevernotbusy** » Fri Sep 19, 2014 12:11 pm

I just got my rebuilt carb loaded back onto the bike, and I was wondering about this mystery hose that runs from the top of the engine back down beneath the carb area. Is this the overflow tube?

I blew into it and pressure built inside, blowing back out of the hose, so this leads me to believe the hose is hooked up to the top ends and takes any overflow gas and burns it. Am I correct in assuming this?

Below are photos of the hose unattached, and attached to the overflow on the carb.

Thanks!

G-Man · Post by **G-Man** » Fri Sep 19, 2014 1:20 pm

The hose from the top of the engine is a breather and should not be attached to the carb. It is vented to atmosphere behind the engine.

The nipple on the float bowl is the overflow vent that also must be vented to atmosphere.

G

garncarz · Post by **garncarz** » Fri Sep 19, 2014 1:24 pm

The hose from the barb on top of the engine goes to one of the holes in the the air filter, as do the two hoses (missing in your photos) from the two barbs on the back side of the cylinders. You also want to run a hose (optional) from the barb on the bottom of the carb to somewhere behind the transmission, as it is an overflow.

garncarz · Post by **garncarz** » Fri Sep 19, 2014 1:31 pm

Here's the service manual:

http://www.scramblercycle.com/uploads/3 ... manual.pdf

And the parts fiche:

http://www.cmsnl.com/honda-ca77-dream-t ... partslist/

Good luck.

nevernotbusy · Post by **nevernotbusy** » Fri Sep 19, 2014 5:18 pm

Awesome. Thanks!

OldStan · Post by **OldStan** » Fri Sep 19, 2014 7:39 pm

garncarz wrote:The hose from the barb on top of the engine goes to one of the holes in the the air filter, as do the two hoses (missing in your photos) from the two barbs on the back side of the cylinders. You also want to run a hose (optional) from the barb on the bottom of the carb to somewhere behind the transmission, as it is an overflow.

I believe the two holes in the air filter are for the two hoses from the back of the cylinder head. The hose from the top of the engines runs by the case under the carbs, any oil will drain to the hole the alternator wires come through. If you run it to the air filter, any oil will soak the paper, and that's not a good thing.

G-Man · Post by **G-Man** » Sat Sep 20, 2014 5:21 am

I concur.... :-)

Because Honda later deleted those connections that vent the inlet valve guides there may not be a place to connect them to the air filter. They can be run to the back of the crankcase or coupled together with a loop of tube. Honda discovered that they were not needed.

G

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Carb Overflow Tube

Carb Overflow Tube