BS32 / 34 carbs --> rubber cap above the needle fuel jet --> compulsory?

[boris.h]

Hi everyone!
I'm making my BS32 carbs brand new. They are rubber caps above the needle fuel jet, just near the main jet... Are they compulsory? how to make them be "sticked" to the tube? they can't....

[Who Dat?]

YES, they are mandatory. If you are "making your carbs brand new", you will want to replace the caps (plugs, actually). New plugs will fit snuggly, but if you look in the float bowl, you will see a post on one side that will press into the plug to keep it in place, so a tight fit is not necessary.

[hampshirehog]

If you buy new ones make sure that they are OEM if you have ethanol in your petrol, otherwise they turn to jelly.

[Guest]

There is a ridge in the float bowl that holds them in.
You bike will run like $hit if you leave them out.

[Nessism]

You bike will run like $hit if you leave them out.

Vulgar man!

[loud et]

YES, they are mandatory. If you are "making your carbs brand new", you will want to replace the caps (plugs, actually). New plugs will fit snuggly, but if you look in the float bowl, you will see a post on one side that will press into the plug to keep it in place, so a tight fit is not necessary.

It took me rebuilding 5 bs series carbs before I had the eureka moment and realized the "peg" in the float bowl held them in. Lol

[londonboards]

This is what we mean:

[TxGSrider]

I know those plugs are needed for the bike to run right, but can anyone explain how the pilot jet works at all with the hole capped off? I don't want to get off topic, I was just curious.

[londonboards]

Here we go:

There is a downward sloping passageway going from the main jet to the pilot jet as shown by the black allen key.



If you shine a light into the pilot jet passage you can see the light down the main jet:



Another good reason to use an ultrasonic cleaner. How many pepes knew that one was there?

The carb bodies themselves are truly works of art. If you look at all the machining holes, plugs and passageways there are. Must have taken lots of man hours to create each one.

[TxGSrider]

Thank you Londonboards! It makes perfect sense now as to where the fuel is picked up from for the pilot circuit with that hole capped.

[boris.h]

ok, so... if the caps do not fit tightly, that is not an issue, finally??
I think I'll make my owns in aluminium...

[londonboards]

I'm only guessing that they put a rubber plug in there as it was easier to assemble than an aluminium one. As long as that little passageway is clear then you should be OK.

At the same time, I can't get my head around someone willing to spend that amount of time and effort to manufacture a plug when they are so cheap to buy. But then time for me is the most valuable commodity.

[rudeman]

There is a ridge in the float bowl that holds them in.
You bike will run like $hit if you leave them out.

Vulgar man!

Yes but so true.

Use the OEM RUBBER ones; they work.

[TxGSrider]

The rubber ones just have to fit reasonably snug as the bowl compresses them a bit when you assemble it.

[boris.h]

ok thanks! if I just put them inside the hole and return the carb, they just fall....

Other ask: about the axial play, when the carb axis move, is it possible to permit a little axial play when moving them? (less than 0.5mm)?
thanks