Topic: Reusing float bowl gaskets

[The Gurg]

Pulling apart my carburetors because I’m wrapping up a rebuild and the carbs are already off the bike. Carbs ran great before. Thought I might dip the jets in carb cleaner and run a wire though them. Blowing out passageways with  air. The rebuilt engine is freshly painted. Don’t want gas leaking on the new paint from the carbs above.

1.) How likely are leaks from the float bowls if I reuse the float bowl gaskets?

2.) My float height is sitting way too low. I don’t even need to measure because it’s so obviously low. Seems like adjusting the tab wouldn’t be enough. Anyone had this issue?

My first rebuild. Honda CB750K5

[ekpent]

 Just me but I never change or even remove/disturb the float bowl gaskets on 750 round top carbs when I clean and dunk them. If they have been changed to junk rubber aftermarket sometime in their life your results may vary.
  Make sure your overflow tubes are hooked up and a good rag or towel is under the bank the first time you fill them up to save fresh paint if there is a problem.

[The Gurg]

I pulled the gaskets so I could scrub with a brass brush a little. Cleaned out where the gasket sits as well. There was a very very small amount of gasket material in the corners etc. I rebuilt the carbs about 8 years ago and didn’t use oem gaskets.

Have lines run from the floats to the floor. So good there!

[The Gurg]

Photos of the gaskets in question.

[PeWe]

Eric, you have lots of experience of carb gaskets!
If you say they work when old, that's the truth.

I have cheap gasket from Cruzinimage. No leak yet after 2 years. But I saved the old hard Honda gaskets.

I have another carb repair set with gaskets and all jets I got a week ago.
I'll use the gaskets only, bowl and throttle top to an extra set of CB750 K6 carbs.

Repair set was very cheap from Taiwan. Seller ensure viton, not swelling. Lets see if that will work
That carb setup will use all stock jets except for main jet, probably another size of Keihin jet. The old gaskets will be saved in my Keihin parts bag.

[The Gurg]

Eric-
Does these being aftermarket change anything for you? Or you think their fine?

[evinrude7]

Eric-
Does these being aftermarket change anything for you? Or you think their fine?

Not Eric but I found some aftermarket carb bowl gaskets to be skimpy compared to stock.

Sent from my moto g(7) using Tapatalk

[The Gurg]

Gasket set (16010-300-305) should be all I need for a rebuild, if I reuse the jets, right?

[bryanj]

If youare doing all the carbs 4 ofthem!!

[Old Scrambler]

OEM gaskets were borrowed from the 305 twin models.........I often soak the gaskets in a 50-50 blend of Marvels Mystery Oil & Dawn Detergent.........sometimes I add Wintergreen Oil......

[seanbarney41]

I am another guy who does not mess with the oem float bowl gaskets...if they are stuck in there?...all the better.

[HondaMan]

OEM gaskets were borrowed from the 305 twin models.........I often soak the gaskets in a 50-50 blend of Marvels Mystery Oil & Dawn Detergent.........sometimes I add Wintergreen Oil......

Ah, that minty smell!
The old gaskets in those carbs will usually work unless they are showing signs of cracks: then they will weep and be wet around the corners, usually.

It sounds like someone changed the floats valves at some point? The modern ones have much stiffer springs and are often taller by about 1mm. This makes the float level quite low if the float tangs are not readjusted to them. Float height in the K5 carbs is 25-26mm, and the cast lines across their floats will be dead parallel with the gasket surface when you set them.

[The Gurg]

I think I’m measuring the floats wrong. I’ve just let them hang, while holding the carb oriented upright. Instead, you hold the carb at a 45° and let the the float valve just graze the float, while measuring right?

[PeWe]

See here
http://www.hondachopper.com/garage/carb_info/float_levels/float_levels.html

[newday777]

I think I’m measuring the floats wrong. I’ve just let them hang, while holding the carb oriented upright. Instead, you hold the carb at a 45° and let the the float valve just graze the float, while measuring right?

Yes on an angle is the correct way.

[The Gurg]

The JIS head on this choke throw from the fourth carb fell off when I took off the nut. Took the top turn of threads with it on one side. Can’t find just the throw by itself on eBay. Thinking I’ll put some loctite on it and use it. Thoughts?

Photo with carb in the picture is before the nut was removed.

[ekpent]

 I know this is no help but I have never felt the need to take any of that stuff apart on the carbs or anything thing on the rack that holds them. Don't make more work then needed unless you have to for some other plan.

[The Gurg]

Yeah, I should have left it. Good advice Ekpent!

Think it’s fine to put it back in?

[BenelliSEI]

The JIS head on this choke throw from the fourth carb fell off when I took off the nut. Took the top turn of threads with it on one side. Can’t find just the throw by itself on eBay. Thinking I’ll put some loctite on it and use it. Thoughts?

Photo with carb in the picture is before the nut was removed.

The set I just did was the same. I just left the lock washer out (the nut went deeper and found some threads) and put a drop of blue loctite. Visible, if you look closely. I’ve done it before, works fine. Next time I visit my favorite aircraft hardware store, I’m going to see if they have a nylock nut that small!

P.S. I reuse floatbowl gaskets all the time, if they still have some flex. The ones in these +50 year carbs were rock hard and got changed. They need some “give” to work.....

[The Gurg]

Great idea BenelliSEI, really not missing any thread, so leaving out the lock washer should work perfect.

Have a specialty bolt warehouse in the midtown area, I’ll see if they have a nylock nut that size, have some other hardware to pickup anyway. You don’t use loctite with nylock or can you?

[Alan F.]

Great idea BenelliSEI, really not missing any thread, so leaving out the lock washer should work perfect.

Have a specialty bolt warehouse....You don’t use loctite with nylock or can you?

I've never heard of a thread locker for nylon screws but it probably exists. Maybe your Specialty bolt place knows more?

[seanbarney41]

It's kinda silly but does work...nylock is considered a thread locking device but it is really only meant to be re-used a number of times.  Every time it is removed and replaced it loses some of its thread lockability.  Locktite or other liquid thread lockers accelerates the deterioration of the nylon...but then you have threadlock from the liquid...so your decision.  Also, that cross in the end is not meant for a JIS or any other driver.  It is staked, intentional mutilation of the threads to prevent removal of the nut...honda did not want the casual maintainer to remove it!

[bryanj]

You can use tread tape as a locker or hylomar

[BenelliSEI]

Great idea BenelliSEI, really not missing any thread, so leaving out the lock washer should work perfect.

Have a specialty bolt warehouse in the midtown area, I’ll see if they have a nylock nut that size, have some other hardware to pickup anyway. You don’t use loctite with nylock or can you?

I would not use loctite if I use a nylock nut.

[The Gurg]

Seanbarney-
Was there a way to remove the nut without harming the staking?


Appreciate the insight BenelliSEI and BryanJ!

[seanbarney41]

You could try grinding or filing it off...but it is so tiny.  Any time i have dealt with it, i just unscrew the nut, hoping it will cleanly cut new threads, and it mostly always has worked.  You just have to be careful to get the tiny nuts started straight when you put them back.  That, or do as Ekpent, and dont mess with them.

[BenelliSEI]

Seanbarney-
Was there a way to remove the nut without harming the staking?


Appreciate the insight BenelliSEI and BryanJ!

Not really..... bit of a crap shoot.

[The Gurg]

Got the nylock nuts and they sit too proud (see photo). Guess I’ll be using pfte tape or loctite.

[BenelliSEI]

Got the nylock nuts and they sit too proud (see photo). Guess I’ll be using pfte tape or loctite.

Omit the lock washer, not required with nylock. And add a small drop of blue loctite. It won’t move. I also find you can’t really snug those nuts down, or the lever gets jammed. That’s why they never really tighten the nut and had to stake them....

[StockRider]

Got the nylock nuts and they sit too proud (see photo). Guess I’ll be using pfte tape or loctite.

Omit the lock washer, not required with nylock. And add a small drop of blue loctite. It won’t move. I also find you can’t really snug those nuts down, or the lever gets jammed. That’s why they never really tighten the nut and had to stake them....

I tightened mine down first, gently cleared the staking with a Dremel bit, and backed the nuts off gently. I plan to re-stake them once I have settled on final choke linkage adjustments and whether or not to do anything about the corrosion on choke levers #3 & #4. Also, I'm waiting on a kit of stainless cotter pins from Amazon in order to replace the little ~1mm ones on the linkage.

[StockRider]

The JIS head on this choke throw from the fourth carb fell off when I took off the nut. Took the top turn of threads with it on one side. Can’t find just the throw by itself on eBay. Thinking I’ll put some loctite on it and use it. Thoughts?

Photo with carb in the picture is before the nut was removed.

Regarding replacement levers, I was tempted by the selection at Yamiya. They have zinc and chrome plated available:

https://www.yamiya750.com/index.php?main_page=index&cPath=246_21_181_143&sort=20a&page=3

I've decided today that I am going to remove as much corrosion as I can from mine, clear coat them, and move on. I prefer to keep the originals, even without re-plating. There is so much character in the way that these were soldered/brazed together and finished..., shows the character of the times.

[BenelliSEI]

The JIS head on this choke throw from the fourth carb fell off when I took off the nut. Took the top turn of threads with it on one side. Can’t find just the throw by itself on eBay. Thinking I’ll put some loctite on it and use it. Thoughts?

Photo with carb in the picture is before the nut was removed.

Regarding replacement levers, I was tempted by the selection at Yamiya. They have zinc and chrome plated available:

https://www.yamiya750.com/index.php?main_page=index&cPath=246_21_181_143&sort=20a&page=3

I've decided today that I am going to remove as much corrosion as I can from mine, clear coat them, and move on. I prefer to keep the originals, even without re-plating. There is so much character in the way that these were soldered/brazed together and finished..., shows the character of the times.

Nice work on the carbs! I agree, keep your original. They look great!

[HondaMan]

The JIS head on this choke throw from the fourth carb fell off when I took off the nut. Took the top turn of threads with it on one side. Can’t find just the throw by itself on eBay. Thinking I’ll put some loctite on it and use it. Thoughts?

Photo with carb in the picture is before the nut was removed.

I've probably got some of these, or at least one.
Is it the choke lever from #4?