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Hey all... my bird has been running rough after not being ridden much at all the past few years (I was traveling very frequently for work) and I decided it was time to redo the carbs. With that said, I have a torn slide diaphragm. I've called everyone and their brother's uncle and haven't had any luck online either. Anyone know of a cross reference that'll fit or know where I can source one?
 

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What/Which part/s are you looking for CRich? Can you see it in the attachment? Something to do with #20 perhaps?

T.
 

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It depends on how that diaphragm is attached some can't be separated from the slide
 

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Its discontinued. I looked around, not even silver in the UK has stock. You can supposedly glue them, but I've never had much luck with that on other bikes. I do have some used stuff sitting around if you're unable to come up with any other fix.
 

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Could you look for a full set second hand on ebay. I got a full set for my cb400 last week very cheap just because of slight damage to my own.
Turned out to be like new!
 

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🏍Bird 1 - Carb 1998 🏍Bird 2 - Carb 1998
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Hi all.
I am bringing back this topic as it seemed the most appropriate from the search I did.

My Carb1, with a good mileage on it has what the mechanic said, old distorted diaphragms. This was 4 years ago :unsure:
He always manage to adjust the carburettor with its vacuum gadget making it run smooth for a time (several months) until it starts again rumbling in constant low revs or while gearing down (small explosions under the tank).

I have being reading the Forum and made me think that actually would be time to solve it using this community way (I got a quote or 400 euros which I think it is an absurd amount).
From the OEM part schematics I understand the part 20 is what I should be looking for (while I could not find Honda originals online, I do see eBay options - mainly in US).

CBR 1100 XX Carb Diaphragm

My question is how difficult is to replace them?
I see in the schematics what seems to be a needle. Does it means tricky adjustments and requires a vacuum tool to readjust the carbs again, correct?
That would be out of my skill bag, but if I understand the required work I may bring the cost down, hopefully.

130563
 

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Changing out slides is fairly straight forward. Replacing the diaphrams (the rubber part) I am not so sure about. Once changed and installed you shouldn't need to resynch as these don't effect the throttle blades. Which is what synching effects.
 

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Changing out slides is fairly straight forward. Replacing the diaphrams (the rubber part) I am not so sure about. Once changed and installed you shouldn't need to resynch as these don't effect the throttle blades. Which is what synching effects.

By slides, I understand the metal blade attached to the rubber itself, right?
I saw a video for the ZZR14 and the rubber was wedged between two disks and was replaceable. Could not find yet for the BB.

I saw the rubber part sold individually, hence my question. But also if I find the diaphragm set (rubber and slide), could make the work easier.

My other slightly dumb question is how easy is to replace them. If no synchronizing is required, I am hopping that:
1. remove the tank
2. remove the air box will give me access to the carb ramp
3. remove the cap and parts identified in the picture inside the red and install following the same order!:rolleyes:

While it sounds simple, I can already guess there will a catch somewhere! 🥴
 

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A couple of guys have used the cbr900 ones and claim they fit and work properly



In fact the seller now lists them for the Blackbird.

 

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Nope you pretty much have it no catches. Just be careful tightening down the screws for the caps. To tight and you could crack them. Make sure diaphram is seated in its groove. And then snug down the covers.
I'd also follow Cbrdeano's recommendations on the replacement parts and installation recommendations.
 

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Thanks guys, just watched a few YouTube videos of people servicing carbs and one in particular explaining the rubber/slide replacement (in a small carb and using some glue which I think is very dodgy, but got the idea).
Overall I have two challenges now:
1. understand if the sliders would have too much wear to the extend that should be replaced
2. buy the rubbers to find out their are not replaced in the slides (so far have not seen any video with this case)

Just ordered from Wales (eBay). Lets see how it goes!
Thanks for your hints.
👍
 

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I have finally find the opportunity to reach my carburettor and check the membranes (while solving the heating issue described in another post).
This is how they look like currently.
The slider seems fine without any signs of wear and the needle also look in good shape.

I wonder how it should look? Is this bad enough to be the reason for the explosions sounds under the tank?

I did order the rubber from CBR900 but they small rubber ring seems to be in the opposite direction (unless I am thinking they fit upside down?)
See the picture from the eBay store. If I position the small rubber in the same direction, the diaphragm seems to sit with the arch up.... I am not sure now how should this fit. Any suggestions please?

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Sit the diaphragm on the carb body so the little ring fits correctly - this will show you which way the piston should be mounted to the diaphragm.
 

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Right, now it is time for the attempt to replace the diaphragms.
I tried to buy one second hand unit to attempt the rubber replacement but was not successful.
My idea was to use this extra glider in case the rubber is not replaceable or does not sit properly.

I will have to take the risk and use one of them for the trial.

I can guess they are a very tight fit, correct? When I gentle try to push it out, there is no visible movement.

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EDIT
Found a video for a CBR900 which according to some sources, use the very same rubber size.
I will try this.

Question is what sort of "glue" is safe to use with petrol to lock the rings back in place??? :rolleyes:
 

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Update

Actually, applying heat made the diaphragm soft and was very easy to pull it out.
I have installed the new one trying to keep it in the right position.

But I have some concerns.
1. if the inner diaphragm ring is secured, since I did not try to force it in with any tool (to avoid pinch it) and assumed that the natural form would pull the rubber inwards.
2. the diaphragm seems considerable smaller (could it be that the old one is stretched because years of petrol fumes?
3. I am not sure how I will secure the diaphragm in place when positioning the lead. It does not naturally seat on the carb body!

See pictures.

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I find that if you use a paint brush handle under the slide ( at the side of the needle ) to hold it up about 20mm or so - you can invert the diaphragm on to the carb body and install the spring and cap.
 

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I find that if you use a paint brush handle under the slide ( at the side of the needle ) to hold it up about 20mm or so - you can invert the diaphragm on to the carb body and install the spring and cap.
That is actually a good hint to try.
I have tried so many times to fit it in place that the new rubber at times, can hold in places for a moment, but not the entire circumference. I will try your suggestion.
Thank you.
 

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Starting to think that the eBay seller sent the wrong diaphragms.
Any way I look, it feels small despite the description saying also the Blackbird.

In the following pictures I have the slider fully inserted. As long as I keep the diaphragm in place with my fingers, it will hold and stretch all around the carb, but once I start releasing it, it jumps off the rail.
The second picture is using CBRDean0 suggestion, with the slider 2cm up and the diaphragm inverted.
It looks even smaller :) and again I need to keep it in place with my fingers or it will just return to the initial position, way far from the rail where it should seat.

About to get mad and in need of psychiatric help! o_O

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Starting to think that the eBay seller sent the wrong diaphragms.
Any way I look, it feels small despite the description saying also the Blackbird.

In the following pictures I have the slider fully inserted. As long as I keep the diaphragm in place with my fingers, it will hold and stretch all around the carb, but once I start releasing it, it jumps off the rail.
The second picture is using CBRDean0 suggestion, with the slider 2cm up and the diaphragm inverted.
It looks even smaller :) and again I need to keep it in place with my fingers or it will just return to the initial position, way far from the rail where it should seat.

About to get mad and in need of psychiatric help! o_O

View attachment 133021

View attachment 133022
I see what you mean - They do look too small for the carb bodies.
Probably worth e-mailing the seller with those pictures and asking for their input.
 
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