CB550K0 Carb Inlet Rubbers

[GTB981]

I have just bought a full set of carb rubbers for the CB550K0 I bought off James beginning of this year. The reason for this was as the only fault I could find with the bike was occasionally it idles high when you pull up to a junction so suspect air leak on the inlet somewhere. The originals are quite hardened and don`t think clamps are sealing them.

Anyway, any tips for fitting ? Soak in hot water first ? use rubber grease or fit dry ?

Thanks for any tips.

Geoff

[kevski]

A light smear of vaseline does the job, and I always keep the rubbers indoors until ready to fit

[hairygit]

A water based lubricant like ky jelly is better, Vaseline is petroleum based and can deteriorate some types of rubber.

[GTB981]

Thanks, agree with Hairygit, been in the latex dip moulding business for a good few years. Vaseline is a no no with rubber. Always keep a tube of KY in the garage......... But red rubber grease will also act as a lube and helps prevent drying out ?

[K2-K6]

I'll not ask how you found that out hairygit

I found (in Plumbase general plumbing supplies) silicone grease branded for "Polypipe" that is used on the push fit plastic plumbing systems. It's virtually inert for most uses, doesn't deteriorate and is completely clear.

I've used it for things like the side panel mounts as they are easy to crack when they get older, also for the rubber type plug caps to stop them sticking to the plugs as it doesn't get affected by temp. Admittedly more useful on cars as it's easy to pull the HT lead out of those bonded type caps.

You can also use it inside the throttle twist grip housing where it won't affect any of the cable sleeves.

[Tomb]

Not saying the opinions about Vaseline on carb inlet rubbers are wrong, but whenever I read about how its petroleum based therefore not good on carb rubbers I have to chuckle. These are the carb rubbers, the thing that the petrol goes through.

[hairygit]

Not saying the opinions about Vaseline on carb inlet rubbers are wrong, but whenever I read about how its petroleum based therefore not good on carb rubbers I have to chuckle. These are the carb rubbers, the thing that the petrol goes through.

I totally get what you're saying, but petrol vapour is sucked through them with vast quantities of air, and chances are with petrol's evaporation rate, they are not in very much contact with petrol, whereas a coating of Vaseline will be permanently in contact with the rubbers, and long term it may be an issue. Given the ludicrous cost of them to start with, my theory is to avoid damaging them as much as possible!

[kevski]

Not saying the opinions about Vaseline on carb inlet rubbers are wrong, but whenever I read about how its petroleum based therefore not good on carb rubbers I have to chuckle. These are the carb rubbers, the thing that the petrol goes through.

I totally get what you're saying, but petrol vapour is sucked through them with vast quantities of air, and chances are with petrol's evaporation rate, they are not in very much contact with petrol, whereas a coating of Vaseline will be permanently in contact with the rubbers, and long term it may be an issue. Given the ludicrous cost of them to start with, my theory is to avoid damaging them as much as possible!

Blonde moment.

There is petrol vapour going through these constantly and whats in petrol vapour (PETROL) thus ensuring petrol is in contact with the rubber for as long as they are installed on the bike,so a light smear of vaseline will have zero effect.

Silicone grease should not be used where there is a chance of it being taken into the engine as metal to metal moving parts are prone to increased wear due to the silicone.

[Colonial-Clive (yindi)]

I used a hot air gun or hair dryer just to warm yo the rubber and they push on easy.