KH 500 Petrol in the inlet rubber

[David Smith]

On attempting to start the bike after fitting a rebuilt monobloc carb (everything to spec) after the winter storage, it fired easily enough but would not pick up and flooded the plugs several times. Eventually pulled the inlet rubber off to check if the slide was sticking and a fair amount of petrol ran out! Not sure if the float was leaking or overenthusiastic tickling, anyhow carb appeared not to be leaking and fired up and ran straightaway with fresh plugs. I think I will drill a small hole in the intake rubber that any future excess of petrol can leak out of so I can both see it and not flood the engine

[adrie.degraaff]

Not a good idear it will run to fast on the false air.

[tony.barnett]

Petrol won't leak out unless the engine is stopped. The inlet runs under vacuum so will suck air in. Not a good idea.

[Simon.Gardiner]

I think the rubber that's being mentioned is the air cleaner side of the carb, shouldn't be much vacuum there unless something's blocked...

SG

[David Smith]

Well it runs OK with the hose off but undoubtedly a bit weaker, so a couple of mm hole is not likely to make much difference, but wll let any pooled petrol out so doesn't get sucked straight into the engine as soon as it fires. Clearly I need to sort any potential leaks out first and tickle the carb with less enthusiasm as it does'nt seem to leak out of the carb visually but might be getting in the air hose!

[paul.jameson]

My 1954 KH has a monobloc carb and the air filter. It would amaze me if my air filter rubber was a decent seal onto the carb. Turn on the petrol, shut the air slide and give the carb a very brief tickle and she will fire up and run reliably, usually first kick. I think your only problem has been holding the tickler down for too long. A second, or at the most 2 seconds is long enough on mine, but I do open the petrol tap before I put my gloves on which gives the carb time to fill if the bike hasn't run for a while.

[David Smith]

Paul

I think you are correct!