tunebike.de -- what is this carb spacer thing?

[cat]

what *is* this thing?
why not just replace the 'swollen' diaphragm?

quote translated by Babelfish from
http://www.tunebike.de/Deutsch/Competit ... gaser.html :

For the MZ Serien vergaser: The carburetor kit for the compensation of the diaphragm swelling, which leads to power loss! At the same time the responsing mode is improved substantially, the motorcycle reacts many more spontaneously and more directly. Are contained in the kit adjustment instruction, nozzle drills, spacer ring, Stolperrohr and screws. Are continued to need (do not contain): Drill 5mm, silicone sealing compound. Several times with best results in series and Stufe1-Motoren tested. Nearly as well as a flat slide!

[keithcross]

I think this ring clamps the diapragm in the right hand carb better. Not to sure though, try emialing Bernard at tunebike and asking him. He is a very helpful chap.

Keith

[DAVID THOMPSON]

hello

it may be a spacer to adjust the diaphram so the slide is moved by the vacume to a better location for proper fuel and air mix

the one thing i did really like about my BMW R90s was 28 years
of no working on BING CV carbs
it had delortho's and i never did any thing to them but clean the float bowls
the saxon tour has a bing cv and it is a pain in the butt ....it idles at a different speed every day

[cat]

I think this ring clamps the diapragm in the right hand carb better. Not to sure though, try emialing Bernard at tunebike and asking him. He is a very helpful chap.

Keith

i eventually saw their English translation, which was better. they say 'enlargement' of the diaphragm. your theory sounds good, but 'swelling' or 'enlargement' suggests the need for a new diaphragm. but the kit also includes jet drills and a replacement venturi tube, so there's more to it than just the diaphragm.

[cat]

hello

it may be a spacer to adjust the diaphram so the slide is moved by the vacume to a better location for proper fuel and air mix

the one thing i did really like about my BMW R90s was 28 years
of no working on BING CV carbs
it had delortho's and i never did any thing to them but clean the float bowls
the saxon tour has a bing cv and it is a pain in the butt ....it idles at a different speed every day

i've got an R100GS - although i only rode it a couple of weeks before it became a 'project'. (i spent thousands on new OEM parts and other things like a Nissin master cylinder and better lights and so on, but i haven't had the time to get working on it.)

i was amazed at how heavy those carbs are. my friend said "the Bings, they're good if you need a hammer at the side of the road, that's about all."

i did, in the few weeks i rode it, experience the other thing about them - on the BMW -- how they feel when they hit your leg.

and one of them, i could not get the main jet out.
yeah, you can imagine how well the airheads must go with Mikuni conversions.

[Fil]

I think the spacer just moves the diaphram up a little higher in relation to the carb (I would guess it goes under the diaphram). I think the purpose of doing this to reduce the 'pull' on the carb slide (the bit with the needle in) as it moves higher up the carb. As the slide moves up (with wider throttle openings), the diaphram will have to stretch that little bit more, thus putting more resistance on the slide as it tries to move higher.
I could be completely wrong of course!!

[cat]

I think the spacer just moves the diaphram up a little higher in relation to the carb (I would guess it goes under the diaphram). I think the purpose of doing this to reduce the 'pull' on the carb slide (the bit with the needle in) as it moves higher up the carb. As the slide moves up (with wider throttle openings), the diaphram will have to stretch that little bit more, thus putting more resistance on the slide as it tries to move higher.
I could be completely wrong of course!!

<sigh> i was never good at carbs. i think EFI is much easier to understand. ..... by 'enlargement' and 'swelling' maybe he (the German writer) meant the stretching you're talking about. that makes sense. better throttle response / "more direct" ... the initial sudden opening of the throttle, the initial resistance of the diaphragm [before the pressure builds up] would be slightly less. but it would also - being slightly higher - make the mixture richer at the closed position. ?