Carb mount....what's your preference and why?

[Timbo]

....rubber mounted or car hose..... And if it's rubber ....what's the secret to keeping it from coming off..

[Chris in Margate]

I persevered with the silicon based hose for a year but couldn't get them to stay on for long.
Trouble free (oh bugger ###@@!!!) for 2 years with ridged rubber mount and fat clip on manifold and thin clip on carb end.
It'll fall off tomorrow now !!

[Timbo]

Why the fat and thin clip Chris?

[Adam_Winstone]

The only mounts that I entertain are the correct ones; correct rubber mount with locating ribs at he correct position for both carb stub and manifold. Get mounts with ribs at the wrong position and you are wasting your time. My personal experience of the cut hose type was not good and I spent as much time on the side of the road trying to put my carb back on as I did riding the bike. These mounts, I bought 2, are collecting dust in my last resort box as I hope to never have to experience them again!

Get the right rubber mount for your carb and you'll have thousands of miles trouble-free.

Adam

[T5-190]

My two pence worth, on most types of motorcycle the carb is normally held by the carb/reed rubber and an airbox. The airbox helps hold the carb and take the weight off the carb rubber. On a scooter we fit a heavier carb and expect the rubber to hold it, under tighten it and it falls off, overtighten it and the same happens. Most German tuners/racer never use carb rubbers with ribs in them, but instead use a plain hose. This type of hose is better with fuel and does not crack or split. But if it does they just cut a new one. Silicon rubber is not petrol proof, in a past life I worked for a company that made F1 re-fueling rigs. Silicon was a real no no.

[Chris in Margate]

Thick and thin clips ?

I guess they are throwbacks from struggling with the hose using everything to try and keep them on.
Thick clip to manifold because there is room and thin clip to carb because the available space on the carb spigot is less.
Anyway... It works well but need to carry mini ratchet and 7 and 8mm sockets.

[phil23fair]

I use the Malossi carb rubber with a 30mm PHBH Dellorto and the ScootRS 30mm reed valve manifold. And the same carb rubber and carb with an MB manifold on a piston ported engine. As Adam says the ridges on the rubber and the grooves on the manifolds are in the correct place and since using the Malossi rubbers I haven't had any problems. I too have suffered the problems with carbs dropping off by using hydraulic hose to try and do the same job - it doesn't work

[Fux]

I have a LTH short manifold and correct rubber mount for my Mikuni TMX 30.

3000 miles trouble free.

Rode another 600 just this weekend to a rally in Denmark and it fell off just as I was entering a petrol station.

[Adam_Winstone]

That's Denmark for you!

[warts]

If using straight hose for want of anything better available, then I would have thought that scrupulous cleanliness would be one of the things to have lined up. Try carb cleaner.
If using straight rubber pipe, then it should be an interference fit, it should not slip in easy.
If the hose is a tight fit as it should be, then something like hair spray as a lube/glue? As well as a clip of course!

At least one of the car manufacturers specifies special narrow clips to hold on the induction pipes (in fact most of their flex pipe to barb fittings) on one of their engines. BMW or Porsche springs to mind, but I'm sure the Japanese have this sort of thing well sorted too. Maybe someone working with modern cars can point in the right direction?

There is a whole field of technology around clips for holding flexible pipe onto fixed barbs or stubs. The trick being to ensure that pressure is applied evenly, around 100% of the circumference of the pipe.
The standard "jubilee" clip apparently not being the best in that regard.

If I had the problem, like on a straight stub at the manifold end, I would perhaps investigate creating a barb - either by welding a bead round the end or machining the manifold (if there was sufficient thickness) to create the barb. Then making sure the clip was narrower and sat correctly behind the barb.

If, as with carbs, there are pre existing grooves, has anyone tried an O ring? With/without the hairspray?
Maybe creating extra ribs with rubber rings would increase satisfaction?

My guzzi has 36mm delorto's which have hung from the same molded carb rubbers it left the factory with in 1979. Splits have happened to others and it became quite common to see people using a cable tie round the open end of the carb to give extra support.
The small block 500cc guzzi's used a similar style, but in smaller sizes, maybe small enough for a lammy?