G1 vacuum line from Crankcase help

[Stinky_1]

I have a new to me G1. It had a little piece of vacuum hose on this nipple coming out the back of the engine. It was really loose, and after one ride it was gone.

I have some driveability issues. The cart starts with the choke and will drive, but I have to choke it every minute or two in order to keep going.

I know, I know, 'Crankshaft seals!', right? Well, I did the clutch side one yesterday then noticed that nipple sitting there, wipe open to the air.

If a small leak in a crankshaft seal is bad then I would guess a 1/8" hole into the crankcase would be worse.

So, does anyone know where that line is supposed to go to? Here is a pic I found online of the engine and it has a hose connected and it clearly goes somewhere. I just cant tell where.

anyone know?

[TD-Bryan]

On my Yamaha powered Taylor-Dunn there is a hose for the crankcase breather that goes up to the valve cover.

[slonomo]

I'm guessing that either goes to the intake behind the carb as a crankcase breather, or it goes to the fuel pump as a pulse line.

[Stinky_1]

Thanks Guys.

Ill have a look today when I get home and see if I can find another spot to plug it into.

I dont think its supposed to go to the fuel pump as that seems to be working. But you never know I guess.

[Lochlin]

My G1 has never has its oil pump hooked up so I am not sure where those vacuum lines go. On my old Columbias, though, their oil pumps go the case like that. Could that be from the oil pump? Understand I do not know on a G1 so I may be way off base. I am just throwing it out there,

[dezrcr822]

That line looks to be the the charge line for the boost bottle and the other line is the pulse line for the fuel pump. The boost bottle is the black plastic tank above the carburetor that has Yamaha written on it. Its a chamber that gets pressurised then discharges into the intake tract to give you a little boost, in a nutshell. I believe they were used from 1983 on with the G1 and were used on some two stroke dirtbikes of the same vintage. My 1982 J17 cart engine does not have the boost bottle or the extra port on the crank case. I have been gathering all the parts to put one on the engine im going to build and need that charge line so if anyone reading this has one they dont need PM me. You can google boost bottle for a more complete discription and theory of operation, its an interesting read.

[slonomo]

The G1 oil pump is gear driven, not vacuum operated.