i have a pair of twin Dellortos that i would like to fit to my project bike , do you think i will still need a fuel pump as the one on the bike is kaput i know it will require a bit of plumbing , any idears
I reckon you will need a pump regardless of the carb type.......there isn't much 'head' on the SS tank to feed them by gravity, so as the fuel drops in the tank, the fuel flow will slow down. Why not fit a Facet Posi-Flow Electric Fuel Pump 1 5-4 00psi 60104 - special offer with straight unions ....with the pump and the filter outside the tank, it will make the plumbing easier, but depending on which Dellortos (I like Dellortos) you have, you might find they have to be horizontal, rather than angled like the Mikunis........Dellortos on the Guzzi LeMAns could be tipped sideways a bit, but I doubt very much that they would have worked well tipped towards the inlet manifold. AL
the dellortos came off my 750s as it was a convertion kit made to replace the the not so good webber so i have all the manifolds that are shorter and more angled , thanks for the tip on the pump
Although I haven't got round to it yet, I worked out that the ideal place for the pump is on the mounting bracket from the same place, which you can fit to the right side of the frame on the flat strip which is the full fairing rearmost fixing. Another small plate is needed. That way, you can have two in-line filters and junk what is inside of the tank. If you keep the return flow set-up, you shouldn't need a flow regulator. AL
to fit a return i take it i would need twin outlet banjos on each carb , i think a have a few of them in the garage and all inside the tank is junk due to it all being gumed up
I think do the return like the Mikuni SS.......fuel supply hose from tank/filter/pump to a 'Y'............one leg of the Y goes to the carbs and splits again to feed them individually; the other leg of the Y is the return. What you need to do is check the pressure that the float needles force open at when the float bowl is full...........stick the carb in a vice at the right angle, fill the float bowl and use a footpump with a gauge on a hose to the carb and see what pressure it blows at..........I'll guess around 12psi.......if that's the case, then the return and the pump rating I posted should be fine. AL
Cheers Al ( thread hijack !) I've just ordered the pump for my Cagiva 750 with nacked vac fuel pump. I will plumb it straight in, it should not need a regulator with 4 psi. There is no return flow, both carbs fed from a common cross-pipe - should be OK do you think ?
you do need one return flow Dave - the SS arrangement works well as AL mentioned - a 'Y' piece that creates a 'head' of fuel constantly topping up the float bowls while the majority say during tickover, goes straight back to the tank. As long as all clamps are secure and hose in good condition it works well.
Cheers Chris, I know that my 900SS has this arrangement, but not the 750 Cagiva. I understand your reasoning and the logic of course - maybe it's because the 900 has an electric pump, but the Cagiva pump is vacuum operated and maybe not positive displacement. ?? Not sure how I would get a return back into the Cagiva tank ?? Ah - maybe the return could go into the pump suction side, so would be a recirc line more than a tank return ??
Beat me to it you b*gger! :wink: ............. but I have had a power cut for the last three hours. AL
Not a good idea....the head of fuel above the pump suction side would mean the return would have pressure against it (which varied as the fuel drops) and that will cause back pressure against the pump..... The best thing you can do with the Cagiva tank..... ...(not that I have looked at one you understand)......for a return inlet, is to see if you can get access under the tank to drill a hole and fit a nicely sealed spigot / union in the hole, but the outlet would have to be above the fuel level as per the SS....... ....best if you did it as an inverted 'U' inside the tank, but if you wanted to, you could even stick one through the top (like the breather stub on the SS).....that way it would definitely discharge above the fuel. AL
Watching with interest as the 900ss i'm collecting this weekend has poor running because of the mikunis. What size are the delortos.. 40's?
