Plastic Floats on Early Carbs

[Rickrod3]

I replaced the brass floats with plastic. I put 15K on the bike with these floats but dealt with carbs over flowing many times. I believe the floats are hanging up in the bowls. I'm having a tough time adjusting them to work freely.
Would the brass ones give more clearance. I think I made a mistake using the plastic ones.
Would appreciate your thoughts on the issue.

TIA
Rick

[bikerphil]

You may be able to bend the floats inward slightly so the bulbs don't hit the side of the bowls, also you can trim the sides of the gaskets down some for extra clearance. Also, if you think the floats are tight on the float pin and binding some, you can take a numbered drill set and slightly enlarge the metal hole on the float to eliminate the binding.

[Rickrod3]

Thanks Phil

I'll try again tomorrow was not getting any where today. Seemed like I was only making things worse. I must have changed the oil about 5X from gas contamination so I determined to get it right.

[mack]

plastic floats

A couple things with plastic floats. You'll notice that one side has a small cut out that is intended to fit down around the sloped air tunnel leading from the air jets in the bell. This tunnel is a steeper angle in the early carbs so that small cut out isn't deep enough to allow the floats to fully seal. You can take a file and deepen that cut out and it won't affect the performance of the float enough to notice. The other thing to make sure of is that the float height is 23mm +/- 1mm for plastic floats. I've run into this myself and the best way to solve the leaking, is do check your fuel levels using hoses. If your using K&L seats and needles, they are known to leak 20% of the time. Mikuni seats with K&L needles will seal but K&L needles don't have consistent shut off points because of the varied spring tensions in the pin. Check them with hoses and if the needles aren't shutting off the fuel supply in time, you'll see the fuel dripping from the starter and air jets in the bell. Adjust the float height up .5mm in the offending carb until it stops. Don't believe for one minute that all your floats will be at the same height.There is just too much variance in the float and needle manufacture. Quality control in China and Thailand is not what it was in Japan 35 years ago.

[mack]

picture

As an example, this is a set of 79 carbs with K&L fuel seats and needles with plastic floats set at 23mm. All four leaked. They didn't stop leaking until I hit 24.5, 24.5, 25.8 and 26.5 mm respectively.
If you look at the fuel levels in the hoses you can see they are too high. The ideal level would be even with the bottom of the washer on the bolt holding the bowls.