SU Carbs

[lazy rambler]

Ian, the k & n came on the su. I have seen them on minilove.co.uk

[chris71920]

On my Vit rocker cover I have 2 breather pipes, one small one which goes to the PCV and theres a large on (like the 1.3) that Im unsure on where to plumb it into.

I have a rockwatt manifold which has a large connection on the left which I assume is the relocated brake servo connection? So cant use that.

How come the vac advance must be relocated from then engine side to the air filter side on the HIF44?

[dan_2k_uk]

The vac adv only needs moving on some carbs as they are all different.

Suzuki engines have no advance at tickover so it needs to be on that side.

Dan

[twiss]

Just remember its better to have no vac advance at all than have it on the wrong side of the butterfly
I didnt want to risk drilling the carb body without a proper pillar drill so I ran static advance instead

[chris71920]

Ok I'll bare that in mind, thanks

Regarding this pic


Mine is slightly different in that the blanked off bit next to the fuel inlet in the pic, has another pipe coming out on mine. Ive connected it to the fuel return hose on mine as if I pump fuel (engine off) into the carb it comes out of here eventually.

But now that its connected if I continue to pump fuel in, it will come out of the overflow pipe at the top. Shall I just blank the lower one off and run the overflow as normal with a hose to the fuel return? Or just exiting under the vehicle further back?

[Edweird]

Ok I'll bare that in mind, thanks

Regarding this pic


Mine is slightly different in that the blanked off bit next to the fuel inlet in the pic, has another pipe coming out on mine. Ive connected it to the fuel return hose on mine as if I pump fuel (engine off) into the carb it comes out of here eventually.

But now that its connected if I continue to pump fuel in, it will come out of the overflow pipe at the top. Shall I just blank the lower one off and run the overflow as normal with a hose to the fuel return? Or just exiting under the vehicle further back?

Right, it sounds like yours is like mine. The one next to the fuel in on your carb is the overflow. The one higher up is actually a vent that you want to have open to the air. As for the other three: breather, vac-advance and the one coming out nearest the manifold plate, I blanked them off.

[chris71920]

Ah ok makes sense. So if I leave the overflow on my fuel return pipe it should be ok? And run the air vent hose somewhere towards the underside?

[Edweird]

Ah ok makes sense. So if I leave the overflow on my fuel return pipe it should be ok? And run the air vent hose somewhere towards the underside?

That's what I thought initially as well, but that caused the carb to pour petrol into the airbox hose and manifold for some reason. If you check out page 12 of my build thread (http://forum.suzukiclubuk.co.uk/vi ... start,110/), it's all about this exact thing, but the long-short of it is:

The fuel in comes from the fuel pump main output.
The overflow (the one next to fuel in) wants an open hose attached to it. The carb only overflows in rare 'emergency' circumstances I'm told and I was advised to run a hose from the carb overflow through the drain hole behind the drivers side headlight, which I've done and I've never smelled petrol yet.
The return hose to the tank should be fitted back to where it was on the fuel pump.
The air vent in place of where the overflow is on that picture should be left open too. I put a short open hose on it that points upwards.
The oil breather and vacuum advance should be blocked off. I did this by putting short bits of hose on them and forcing a bolt or screw into the end of the hose.

[chris71920]

Ok I'll do all that sounds about right to me. Although I can't reconnect the fuel return to the pump as its no longer there (1.6) so block off or just vent it higher up?

[Edweird]

In that case, block it off or put it on the overflow, yeah.