Technical Carb question

[JonPiz]

I have rebuilt a 650 engine for my 500R and just noticed the IMB28 carb I bought has two inlets. I guess that’s not right

 

[JonPiz]

So I understand it is the fuel return. What do people do with this, do they just block it or feed it back into the fuel line. I read there are possibly starting issues with the latter?

 

[smart51]

One of the inlets is an outlet. If you look inside the carb, the hole to the outlet is tiny. Some people block off the return. Mine is blocked off. Others fit a hose between the carb outlet and a T connector before the fuel pump. That way, excess fuel circulates a bit. It is probably a good idea to do this.

 

[the hobbler]

One of the inlets is an outlet. If you look inside the carb, the hole to the outlet is tiny. Some people block off the return. Mine is blocked off. Others fit a hose between the carb outlet and a T connector before the fuel pump. That way, excess fuel circulates a bit. It is probably a good idea to do this.

Yes, the fuel outlet is the one pointing to the front of the car when the carb is fitted. Personally, I think that it is better to fit a simple 'return' rather than block it off. I originaly had a 28IMB on my engine so I fitted a METAL 'T' piece in the fuel line at the side of the engine bay and then led some fuel-hose from the carb, down to the 'T'piece round the back of the big air inlet trunking. I threaded rhe fuel hose through some water-hose (for protection) and secured it in place with a couple of rubber-lined 'P' clamps. Having the fuel circulating does keep it cooler and help prevent a problem with hot-engine starting.