Carb rubbers question

[Peterplank]

Hello all, I have removed my carbs from 500K1 to clean out and replace float valves & seats after as they are overflowing.
Question is.. the inlet rubbers are very hard and stuck and I reckon they need replacing as I can't see they will go back on as so stiff.. are the pattern ones ok or oem best / better ? Are they fexible when new and is there a best re installation order with rubbers / carbs / airbox side ?
Thanks for any help with this.. as I'm sure you know it's all very tight in there. )

[Johnwebley]

I would go for the OEM rubbers,

Fit to the bank of carbs, use some rubber grease on the alloy inlet ports,

And wriggle the whole assembly together,



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[deltarider]

It's your choice. In the pic the 4 new OEM boots I have bought at the dealer decades ago. The rack has been of twice, since I have bought these, but so far I have not felt the need to replace the old ones. Why? Simple: I had no indication whatsoever there was any leaking. So I decided to leave them alone. They still don't leak. This is my policy always. Now if you're deep in the engine doing an overhaul, it's another thing and ofcourse it's best then to replace all rubber parts.
For the rest, I am always amazed to learn how long things live, if you simply leave them where they are. But I have to admit, many will not agree with me. I have lots of parts still waiting in their plastic bags.

[Peterplank]

Is it possible to install bank of carbs then wiggle in air filter rubbers ?
Just trying to figure best way of putting all back in without mashing everything..
)

[Johnwebley]

Awaiting answers with interest


PS,I have never done it

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[mickwinf]

its a fiddly job and different people have different methods. the air filter box should be un bolted and pushed back to give a bit more space. I remove the airbox to carb rubbers or push into airbox out the way. To remove carbs i prefer to unbolt the manifolds from head and remove as an assembly and replace in the same way. then the airbox rubbers have to be squeezed in which is the most fiddly bit. good luck!

[DomP]

Get the plasters out ready is my advice, oh and a cold pint for when you've finished, you'll need it.

[Peterplank]

Thanks for the replies, I'll report back when I've put the 200 bits back together 😁

[Bryanj]

Also learn a different language to practice swearing in so you dont upset the neigbours!

[Seabeowner]

I found that a heat gun helps on the carb to inlet manifold rubbers. I have used a set of pattern parts on one of my bikes and they were adequate. £18 or £42 from DSS. Genuine may be available from local Honda dealer.

[JezzaPeach]

I did mine recently and had taken out the filter box to move the air box back slightly. I took off the clamps at either end as it helps the rubbers squish, a trace of red rubber grease in the rubbers, and worked the front on first then upwards at the back bit by it. Pushed all on firmly (rubbers were soft) and clamps back on. Fired up instantly!

[Oddjob]

Fit new orings on the manifolds. Bitch to find they leak after fitting.

[exvalvesetdabbler]

If there is some doubt if they leaking on the engine side of the carbs, spray some WD40 on the joints with the engine running, you will hear a change if they are sucking in more combustible material.

Regards
Dave

[Gromitdog]

Hi Pete
I have found If you put some lube on the engine inlets as suggested then put the air filter box in you can gently slide the carb bank in from the R/H side of the engine and up onto the rubbers on the inlet sides its not easy  ( charioteer building is how I describe it 😂 ) when they are on put a towel under the carbs to hold them up in place but the towel still gives you some up & down movement then move the air box fwd and starting with he middle rubbers squeeze them in half and tease them in to place. I then slave in the air box bolts in to give the correct height then fit the inlet jubilee clips and nip them up then fit the air filter to carb jubilee clips and nip them up. Then nip up the airbox to ensure it's in place with a tiny bit of movement .
Double check the rubbers are all sitting nicely if so do them up fully and then do the same to the air filter box.

Its certainly not easy when fitting new rubbers, But its easier the next time as the will have shaped themselves

Good luck Nige

[deltarider]

Since I had 4 new OEM boots (carbs<->engine) lying around in their plastic bags for decades, I did something against my principle* and have removed the 4 that have been on my bike since 1976 and have served over 140.000 kms. All 4: no cracks and all 4 100% still airtight. Carbs have been of 3 to 4 times in 45 years. This is proof that if you have no indication for airleak, you can reuse these boots. They are robust and quite thick.

* which is: don't fix what isn't broken. I had no indication for any airleak.