Cylinder 1 getting hot.

[DEmily]

So should I put small filters on those hoses? I assume that these hoses being open will not adversly effect the engines internal vacum?

[skids]

I would thank that would be better than plugging them off, yes.

Originally posted by DEmily
So should I put small filters on those hoses? I assume that these hoses being open will not adversly effect the engines internal vacum?

[DEmily]

So what is the exact purpose of these hoses?

[steelcat]

They equalize the air pressure between the float bowels and the air intake manifold. That is why on the older carbs they went to the air filter box which has a maniflod running back to the carbs. Yamaha calls it the "oil separator" (2h7-14434-01-00) . One auto. carbs the tube is called the balance tube. The inkake is a vacum and the float bowels would be at atmospheric pres. thus forcing fuel through the carbs

[DEmily]

I am beginning to understand the complex nature of these things. I have built many hypo auto engine in my time, but this is certainly a new experience.

[Shuriken]

XSives call the carb experience carb hell. However, once the carbs are understood, they really make sense. The fuel injection conversion is drawing my attention these days though.

Ben

[DEmily]

Thanks everyone for your assitance. I unplugged the hoses that use to run to the airbox and the old girl took off like a rocket. Great exceleration, sounds really awesome with the new exhaust.
I am still have some problem with number 1 and 2 running rich. I pulled the carbs and the main jets in those carbs are marked as 137. I remember buying the carb kits and endded up getting them from two sources. The ones in 1 and 2 are from a K&L kit where as the others are from Yamaha (137.5) Is it possible these main jets are larger than the original ones?

[CA.XSer]

The ones in 1 and 2 are from a K&L kit where as the others are from Yamaha (137.5)

The K & L kit mains are to big even though they are marked 137. That is why 1 and 2 are running rich.