Topic: Question about sticky floats - Solved

[cookindaddy]

I am trying to diagnose float bowl overflows on a 750K7 PD carb that I've rebuilt. The gas is clean. The tank is clean with no rust and has a new filter and a new gas line. I have set all the float heights very carefully but am getting what seem to be random overflows as I try the carb with gas. Also, the heights of the fuel in the bowls (using a transparent tube hooked to the drain and held up to the side) do not seem to be coming out evenly.

I'm looking all over and came across this sentence in Hondaman's book at the top of page IV-14 (I have the paperback version). He is talking about fixing small burrs that form on the float support posts that are carved by the edges of the float tang bracket. These cause the float to catch and should be checked and filed off.

Then he says:

"While you are filing on the float arm, consider narrowing the width of the pivot a little bit, too. The tolerances on these parts can be such that the pivot is too long, which makes for sticky pivot action under some circumstances. Below is a picture of a trouble free unit: compare this width with yours if you are having intermittent overflow troubles"

There is no picture below that relates to this in my copy.

I can't wrap my brain around what Mark is telling me. Mark if you are out there or someone else can explain this to me in other words, I'd appreciate that. This is precisely my issue right now and it is keeping me from riding and causing me to spill a lot of gas on my garage floor!

Thanks

[Ved]

I think what he means is making the pin that goes through the floats pivot point shorter. In some instances that pin can end up touching/rubbing on the bowl causing issues. Ive never done this myself, but then again I always clamp my carbs in a vice(right side up) with the bowls off, to check to see if any are sticking. I also converted an old coffee can into a temp gas tank with a petcock that I can hang above my bench and hook to the carbs.

Be sure not to put the floats in upside down. It's all too often a common mistake. My CB750A I bought had all 4 floats upside down. No wonder the dude couldn't get it running right. I can see how easy it is to put them in upside down as it just seems correct to put the flat side of the floats up.

[cookindaddy]

I think that this is solved. I followed Mark's suggestion to check the edges of the carb casting where the float axle touches and polished those and the ends of the float axle and the pin. By tilting the carb assembly in my hands slowly I could see that all the floats moved together with none of the binding that seemed to be happening before. Once more a careful check of the float heights, put it back in, hooked up the gas. No leaks and the fuel levels seem to be all the same and at the right height.

Started it up and it goes great! First ride of the season!