G1 crankcase breather

[carlschaub01]

So I’ve been rebuilding my g1 for a couple of weeks now and have been coming on here for any questions I’ve had and everyone I’ve had someone has already had and been answered. But there’s one I can’t find, underneath the carb on the back of the block there’s 2 little what looks like to be breathers, the one had a hose going to the fuel pump which was the bigger of the 2 but the tiny one I can’t seem to find what it goes to. Any ideas?

[smallblock450sl]

That would be for the air chamber. You can just plug it off if you don't have the chamber, but you will also need to plug the manifold hole.

[Lochlin]

Hey smallblock, he may be referring to the vacuum lines on the case? If so, both those are nipples for vacuum lines. 1 for the fuel pump which you still have connected. The other is for the oil pump which has likely been intentionally disabled. Plug it and make sure you premix your gas.

[smallblock450sl]

Originally Posted by Lochlin

Hey smallblock, he may be referring to the vacuum lines on the case? If so, both those are nipples for vacuum lines. 1 for the fuel pump which you still have connected. The other is for the oil pump which has likely been intentionally disabled. Plug it and make sure you premix your gas.

Sir, I don't like to "call out" poster's, but your completely wrong. The only oil pump lines are from the oil tank, to the carb and the muffler jet sensor. I may have forgotten more then I remember, but I know my Yamaha's.

[Lochlin]

Originally Posted by smallblock450sl

Sir, I don't like to "call out" poster's, but your completely wrong. The only oil pump lines are from the oil tank, to the carb and the muffler jet sensor. I may have forgotten more then I remember, but I know my Yamaha's.

I hear ya which is why I phrased that as a question rather than a statement. I know carts ok but am still learning the G1.

[carlschaub01]

Yea the one goes to the fuel pump which is the larger one, so your saying the smaller one goes to the oil pump that is long gone?

[cgtech]

Just sayin' , if smallblock says it ain't so, it ain't so. I don't recall any crankcase hoses going to the oil system either.

[mikeasis]

smallblock is correct. one goes to the fuel pump and one goes up to the air chamber. the air chamber then has a small hose that goes into the intake boot. tired to get you some pics but that's a heck of a spot to try and snap a photo of

[Gravesdiesel]

What does the air chamber do? Will removing it or modifying it make any difference?

[mikeasis]

I think it was on 84 and later g1s, sometimes referred to as a boost bottle and honestly i have no idea its purpose. I think ive seen posts on here where people plug off that intake port if the bottle is cracked or damaged.