Author Topic: float valve seats (Read 1210 times)

evinrude7 · « **on:** February 28, 2017, 04:18:15 PM »

do the float valve seats on a 76 cb750 contain springs? reason i ask is only one of my valves seem to bounce back after pushing the float against the valve. or do the valves just run off gravity?

kerryb · « **Reply #1 on:** February 28, 2017, 04:37:44 PM »

Yes, but the springs are in the needle, not the seat. If yours aren't "springy" you may be able to rejuvenate them by soaking in carb cleaner (real carb cleaner, not pine sol or some other substitute that will attack the metal) , then give the plunger (little pin on top) a gentle push and see if it springs back. They are pretty tolerant of gunk and neglect.

evinrude7 · « **Reply #2 on:** February 28, 2017, 04:43:34 PM »

kerryb, so you say the springs are in the needle. which needle? do you mean the actual float valve?

kerryb · « **Reply #3 on:** February 28, 2017, 04:53:48 PM »

Give me few minutes, i'll get you a picture.

evinrude7 · « **Reply #4 on:** February 28, 2017, 05:09:33 PM »

thank you sir. i've looked in the manual and can't seem to locate it.

kerryb · « **Reply #5 on:** February 28, 2017, 05:25:37 PM »

Picture 1... needle in the seat, in the carb. (carbs are very similar to yours, not exact.)
Picture 2...needle sitting alone on the desktop, small pin on left end is spring-loaded.
Picture 3...needle with the spring compressed with needle-nose pliers. DON'T use pliers on yours, only fingers.

hope this helps.
I cleaned my first set of carbs a couple years ago and this forum is the only reason I succeeded...thank you everyone!

Evinrude, consider buying hondaman's book, Lulu press, it is invaluable for pictures and knowledge.

evinrude7 · « **Reply #6 on:** February 28, 2017, 05:46:34 PM »

kerryb, thank you tremendously. well done explanation. i'll have to pull the carbs off again. getting a stock airbox and filter soon. should be here friday. hopefully releasing those spring loaded ends and stock air will fix a lot of my throttle issues. thank you sir.

Don R · « **Reply #7 on:** February 28, 2017, 09:24:42 PM »

Aside from that they are gravity operated, I had a set with springs so weak they didn't work, I got a new set and cured a few problems. When you check the float height you need to see the spring needle and observe the point at which it closes the valve.

evinrude7 · « **Reply #8 on:** March 01, 2017, 05:39:40 AM »

thanks don.

flybox1 · « **Reply #9 on:** March 01, 2017, 06:49:23 AM »

Quote from: evinrude7 on February 28, 2017, 05:46:34 PM

hopefully releasing those spring loaded ends and stock air will fix a lot of my throttle issues. thank you sir.

The spring function of these valves only aids in ceasing the flow of gas to the carb bowl they came out of.
If it were an issue, you'd have a constantly overflowing carb.
Beware of aftermarket replacement float valves if you decide to replace them. While they may look the same, small differences can introduce many problems.

evinrude7 · « **Reply #10 on:** March 01, 2017, 06:55:45 AM »

flybox, actually my wife called me at work yesterday. she smelled gas out in the carport. had her turn the petcock off as i forgot to do so that morning. sure enough when i got home #4 was leaking. probably dropped half a gallon between 7am and 1pm when she called. maybe more.

flybox1 · « **Reply #11 on:** March 01, 2017, 07:03:04 AM »

If the internal spring is soft, or wont release, it will never adequately shut off the fuel flow (until you manually shut it off at the tank)
Makes stopping at intersections an interesting experience

Glad it didnt start a fire $:-\$

evinrude7 · « **Reply #12 on:** March 01, 2017, 07:07:32 AM »

no joke. thankful for all the help on here. my wife is an ex-sargeant of the fire dept. she's on top of these things.

evinrude7 · « **Reply #13 on:** March 02, 2017, 07:59:05 AM »

just pulled the carbs off again. i had 3 of the float valves upside down. duh.

side question: is there any product available that rejuvenates old seals and rubber? my intake boots are rock hard and my carb bowl seals are limp.

flybox1 · « **Reply #14 on:** March 02, 2017, 09:36:39 AM »

Wintergreen oil.
I place about 4oz in a double ziploc baggie with all my carb boots.
2 days of shaking and rotating these and they are much more pliable.

http://forums.sohc4.net/index.php?topic=62328.0

ekpent · « **Reply #15 on:** March 02, 2017, 11:41:06 AM »

Quote from: evinrude7 on March 01, 2017, 06:55:45 AM

flybox, actually my wife called me at work yesterday. she smelled gas out in the carport. had her turn the petcock off as i forgot to do so that morning. sure enough when i got home #4 was leaking. probably dropped half a gallon between 7am and 1pm when she called. maybe more.

You might want to take a whiff of your oil in the engine in case it leaked so badly that gas got in the crankcase as well.

evinrude7 · « **Reply #16 on:** March 02, 2017, 07:17:27 PM »

thanks ekpent and fly. wintergreen oil. ok. what about carb bowl gaskets? anything to bring those back to life?

flybox1 · « **Reply #17 on:** March 03, 2017, 06:25:50 AM »

Quote from: evinrude7 on March 02, 2017, 07:17:27 PM

thanks ekpent and fly. wintergreen oil. ok. what about carb bowl gaskets? anything to bring those back to life?

new ones are cheaper, and better than reviving old ones.

http://4into1.com/float-bowl-gasket-4-pack-16129-268-004-honda-cb750k-cb750f-1969-1976/

evinrude7 · « **Reply #18 on:** March 03, 2017, 04:05:32 PM »

thanks

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Author Topic: float valve seats (Read 1210 times)