Topic: Best place to buy intake rubbers + clamps

[Floshenbarnical]

Hi all,

I've had these carbs on and off so many times I've noticed a little wear and tear on the intake boots, and the clips are getting stretched. I know you can get a set of each almost anywhere, but the quality is not the same. Where's the best place to get these particular items? 4into1 has burned me on a couple mediocre items.

[PeWe]

David silver (DSS) for Honda stock rubbers.
(CB750)

[Doobie]

Other than stock, I trust the K&L boots, which are made in Japan.

[MauiK3]

Yamiya always carries high quality parts, Honda and repro.

[HondaMan]

The modern iteration of these boots can be a little problematic: here's what you'll need to know to sort it out.
The modern boots are about 1+mm smaller on their OD than were the old ones. This means that the old clamps, or even new clamps of the old size, frequently (most of the time) leak vacuum. This causes all sorts of problems, like blackened sparkplugs and erratic throttle (I hear about it a LOT).

You can resolve it in a couple of ways, though.

One way is to make some thin strips of bras or aluminum to lay into the grooves on the rubber, then put the clamps over them and tighten normally. This works with either your old clamps or new OEM clamps, but takes some time to do.

Another way is to get clamps that are both adjustable, and that will not stretch out. The Oetiker clamps are adjustable (and look quite different) and can be tightened too far, actually cutting the new hose right off (don't ask...), but will solve the problem forever. They don't fit very well at the carb side of the hose, but that is not usually where the vacuum leaks develop: that happens at the head side. The Oetiker clamps fit there, nicely. They are airplane parts, and pricey. The part number is 050-9 at Aircraft Spruce
https://www.aircraftspruce.com/catalog/pnpages/055-9.php

[willbird]

Another way is to get clamps that are both adjustable, and that will not stretch out. The Oetiker clamps are adjustable (and look quite different) and can be tightened too far, actually cutting the new hose right off (don't ask...), but will solve the problem forever. They don't fit very well at the carb side of the hose, but that is not usually where the vacuum leaks develop: that happens at the head side. The Oetiker clamps fit there, nicely. They are airplane parts, and pricey. The part number is 050-9 at Aircraft Spruce
https://www.aircraftspruce.com/catalog/pnpages/055-9.php

I just installed a pair of these on cyl 1. They fit well both places. Looking in at #2 though I can see things are tighter between the boot and the carb bracket on the carb side.

[PeWe]

I use zip ties preshaped with a heat gun. Used an old bad carb boot for shaping and cut in correct lenght.
Smooth side to rubber.

Just find black zip tie with correct width.
Std ss clamps.

My K6 with other carbs have 12mm wide clamps. Zip ties ensure pressure where needed. More support with 12mm, less tightening force.

#
#
Honda stock carb boots are softer than back in the 70-80's.
My K6 stock carbs were fastened by clamps in carb boots only back in the 80's. Pod filters.

No cracks in rubber close to inlet spigots as the later can.

[smee]

Hi all,

I've had these carbs on and off so many times I've noticed a little wear and tear on the intake boots, and the clips are getting stretched. I know you can get a set of each almost anywhere, but the quality is not the same. Where's the best place to get these particular items? 4into1 has burned me on a couple mediocre items.

I purchased these for my 1975 CB750K5 that worked great: https://z1parts.net/honda-cb750-carburetor-boots-insulator-a-and-b/

I used the original clamps that were still in good condition with success and no leaks. You can get clamps from VintageCB750 if needed.

[Floshenbarnical]

David silver (DSS) for Honda stock rubbers.
(CB750)

FORTY DOLLARS EACH?? Forty entire dollars!

[willbird]

David silver (DSS) for Honda stock rubbers.
(CB750)

FORTY DOLLARS EACH?? Forty entire dollars!

For fun look and see what a NOS points cover goes for lol

[Kelly E]

David silver (DSS) for Honda stock rubbers.
(CB750)

FORTY DOLLARS EACH?? Forty entire dollars!

For fun look and see what a NOS points cover goes for lol

Or a 4 into 4 exhaust system.

[seanbarney41]

Or consider that many other motorcycles from this era  (and some not even this old!) just don't have any new parts available at all.

[PeWe]

Aftemarket carb boots can crack quickly wich makes them even more expensive lifetime wise.

Then what a leak can cause adds up on the bill.

Here "OEM" carb boots, a set delivered in one bag.
2-3 cracked where inlet spigot starts.

The molded stamps look exact as Honda bagged ones. Except for date, "pointer in a clock circle".

Used max 4 seasons 20.000 km. Those cracks can have been there for a year or 2 struggling with carb jetting.
Cracks hidden under the clamps.

Carbs strapped to frame with rubber spacers to avoid bending forces on boots. Carbs can not jump up-down.

This made me to use nylon  zip ties under the wider clamps, not tightened that hard.
Later Honda bagged boots are also rather soft. Clamp can dig into the rubber when tighten it. The earlier boots where not like this.

One of the boots had a crack almost 180*, the other a little less.

Good idea to have a look under clamps after a few years.


#
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DSS UK take $25US each + shipping, ca $120US.
For me + ca 30% in tax and customs on total + shipping. So $160 it will be when home.
Order from Germany will not be cheaper.

https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972-USA/part_169495/

https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972-USA/part_169494/

JTmarks77 USA
https://www.ebay.com/itm/225643611495?hash=item3489684567:g:ycwAAOSw5ZBWFswq&amdata=enc%3AAQAIAAAAwIaTLB0syCXmoPsKmjCkGQy5qHEHKJU9sUb6hBG33sKYdiNgnkSVR5m%2BO7bkvCcXEnVOsQ1ATx1gIoTmbzbOYm7gKScHQEsJeh4xK8a5CUSkOV7rSItX%2BHLXtAxAJfXDQcYLndN9AB%2FHCN3QPeWhUxmTX%2FmKUvsNQYoOeg%2FYSlUkbN5QhfKyuccJUK%2F9qwntNvbMoVDGDGO1ADQNNfnXax4s5hlaKwdUjDB92l7q%2Fl4C7Otwoarr9w4d53rAMVn7FA%3D%3D%7Ctkp%3ABk9SR4qb_O-sYg

[Floshenbarnical]

I inspected all the boots quite intensively and submitted them to a macguyvered vacuum test. 1, 3, 4 are all airtight. 2 was leaking minorly, so I’m just going to replace that one.

[JamesH]

If anyone needs perfect reproductions of the original ‘non ribbed’ airbox/intake clamps, I sell them here:

https://Carbclamps.com

Happy to offer a 20% discount to forum members. Pm me for a discount code.

[MauiK3]

That is awesome that you are doing these!!!!

[willbird]

Another way is to get clamps that are both adjustable, and that will not stretch out. The Oetiker clamps are adjustable (and look quite different) and can be tightened too far, actually cutting the new hose right off (don't ask...), but will solve the problem forever. They don't fit very well at the carb side of the hose, but that is not usually where the vacuum leaks develop: that happens at the head side. The Oetiker clamps fit there, nicely. They are airplane parts, and pricey. The part number is 050-9 at Aircraft Spruce
https://www.aircraftspruce.com/catalog/pnpages/055-9.php

I just installed a pair of these on cyl 1. They fit well both places. Looking in at #2 though I can see things are tighter between the boot and the carb bracket on the carb side.

Update, these fit into all 8 required places on my K2.

Bill