Replacement float valves

[Snakeoil]

On the two vintage Hondas I've worked on, both use a float valve that has a small plunger and spring that rests against the float lever. Is that truly a necessary feature for these engines? Both the vavles in my CL77 are worn, probaby from vibes. I've not been able to find viton tip replacement valves so it's either stock (megabucks) or run of the mill viton tip replacements.

Anyone know of a viton tipped replacement valve available for these carbs?

Anyone ever used a valve without the sprung plunger with success?

Did a search of this site, by the way and found nothing on viton tips or non-plunger valves.

Thanks,
Rob

[brewsky]

I've used the Keyster replacements in my CA with no problem.
They are not rubber tipped.
I did notice the Keyster valve had a much weaker spring though.
As long as you replace the valve and seat together as a set it should be ok.
If you are dead set on a rubber tip, take the seat and tip to a local dealer and see if they can match it up with something from a different model.
I know some Yamahas use the rubber tip variety.
I needed some weird size o rings and washers for my 750 carbs and found some for an Artic Cat ATV that fit perfectly.

[Snakeoil]

Thanks, Brewsky. Keyster kits were my fallback plan. I think the viton tip is more appropriate for an engine that vibrates like the 305.

Finding a dealer that will look for a similar valve in his parts is hard to find. The kids behind the parts counters can only look up numbers. Most of them come and go like underwear so you never find anyone with any experience. I have one dealer that might be able to help me. I was thinking about trying NAPA or similar car parts vendors. It's that little spring plunger that has me wondering.

My carbs both leak out the overflow when I park the bike. Not much, just a bit. My guess is the valves are not sealing really well so any fuel left in the fuel lines after the petcock is closed dribbles in and runs out the tubes.

Anyone else have experience with replacing these with similar but not OEM valves?
Thanks,
Rob

[LOUD MOUSE]

I use KEYSTER kits with all my rebuilds. .....lm

Thanks, Brewsky. Keyster kits were my fallback plan. I think the viton tip is more appropriate for an engine that vibrates like the 305.

Finding a dealer that will look for a similar valve in his parts is hard to find. The kids behind the parts counters can only look up numbers. Most of them come and go like underwear so you never find anyone with any experience. I have one dealer that might be able to help me. I was thinking about trying NAPA or similar car parts vendors. It's that little spring plunger that has me wondering.

My carbs both leak out the overflow when I park the bike. Not much, just a bit. My guess is the valves are not sealing really well so any fuel left in the fuel lines after the petcock is closed dribbles in and runs out the tubes.

Anyone else have experience with replacing these with similar but not OEM valves?
Thanks,
Rob

[flathead]

Rob,

Something that you might check is the condition of the brass vent/overflow tubes in the carb bowl. I just finished up a CB750 K2 that I could not stop from leaking at the overflows (similar design Keihin carbs as the 305's). I put in new needles and seats, old needles and seats, new floats, old floats, tried both the rubber tipped and plain needles (if I'm not mistaken the 75' CB750F has the rubber tip), set the floats at least a dozen times and still had gas seeping from the overflows. Found out the problem was that 3 out of the 4 brass tubes had a crack close to the point that they pressed into the bowl. The crack was so small that you had to have a magnifying glass to see it. A good way to check them is to remove the bowl, hold it level in a vice, and fill it with gas, mineral spirits, or whatever and watch for a leak out of the hose barb at the bottom. I've never seen this in the dozen or so 305 carbs that I've done previously so it may not be an issue but would be something to check before you go thru a bunch of needles if you can't get them to stop leaking.

Mark

[e3steve]

Rob,

Something that you might check is the condition of the brass vent/overflow tubes in the carb bowl. I just finished up a CB750 K2 that I could not stop from leaking at the overflows (similar design Keihin carbs as the 305's). I put in new needles and seats, old needles and seats, new floats, old floats, tried both the rubber tipped and plain needles (if I'm not mistaken the 75' CB750F has the rubber tip), set the floats at least a dozen times and still had gas seeping from the overflows. Found out the problem was that 3 out of the 4 brass tubes had a crack close to the point that they pressed into the bowl. The crack was so small that you had to have a magnifying glass to see it. A good way to check them is to remove the bowl, hold it level in a vice, and fill it with gas, mineral spirits, or whatever and watch for a leak out of the hose barb at the bottom. I've never seen this in the dozen or so 305 carbs that I've done previously so it may not be an issue but would be something to check before you go thru a bunch of needles if you can't get them to stop leaking.

Mark

Great info, Mark. Also, don't forget to pinch the floats together slightly before refitting the float bowl to prevent them from binding on the sides/gasket; a sticking float can manifest itself as a leaky needle valve. Thanks to Ed (lm) for that particular nugget of info!

[davomoto]

I have had 3 or 4 305 float bowls with a cracked brass vent tube! I found brass tubing at the local hobby shop that was just an RCH larger O.D. I chuck it my drill press, turn it down a tiny bit. I then cut it to the exact length of the old tube, and press it in the bowl. It has worked quite well for me, and I went through the same ritual as you trying to get the carbs to stop leaking!