1983 Honda CB750SC Fuel Inlet Valve (Vacuum??)

[MisterCB750SCMoto]

Can somebody tell me how this gets put back together. I’ve had it put two different ways, but gas is still not going through!? This routes from the petcock to the carburetors. I’ve looked it up as much as I could, how the fuel line goes & vacuum line & air vent line… my bike starts but I’ve had to manually put gas in the fuel bowls. I was told once I do that & she starts, this vacuum fuel inlet thingy will click on and start sucking fuel and delivering it to the carbs and engine… didn’t do that so I assembled it the other way, w the spring on the other side. Idk if someone can send me pictures of how it is done!? I’d very much appreciate it!!! Thank you!

 

[brettp]

Do you have to keep it? I removed mine and went straight gravity feed.

 

[MisterCB750SCMoto]

Do you have to keep it? I removed mine and went straight gravity feed.

No I don’t have to at all. I tried bypassing it already. How would I go about doing that.? When I did it, no fuel would go into the pipe fitting. Idk if it’s bc the bike wasn’t starting at that point. I had just got her started (have a previous post as to why she wasn’t starting). She only starts now if I manually put gas in fuel bowls. She was idling real high, so I adjusted the idle screw, got her to 1k rpm’s, but when I go to give her some throttle she just shuts off!? Is that bc she doesn’t have any fuel getting to her, only the gas in fuel bowls.? And bypassing the fuel vacuum
Inlet thing lol, I just take fuel line from petcock straight to the T pipe fitting that connects carb 1 & 2, right.?

 

[brettp]

Yes, but you need to cap the nipple on carb 2 (i think) that goes to that vacuum operated thing.
If your petcock is vacuum operated, that needs to be replaced, too. OR, you can connect the nipple on carb 2 to the vacuum line on the petcock. What petcock do you have? Pics, please.

 

[MisterCB750SCMoto]

Yes, but you need to cap the nipple on carb 2 (i think) that goes to that vacuum operated thing.
If your petcock is vacuum operated, that needs to be replaced, too. OR, you can connect the nipple on carb 2 to the vacuum line on the petcock. What petcock do you have? Pics, please.

Eating dinner w wife n son & I will send over pics! Thanks for your help. And yea I went to autozone n bought some of those rubber caps and capped the vacuum port. I will send pics of this too. Also, the black plastic T piece that connects carb 2 & 3 in the middle, that is just the air vent tube correct:? No need to cap that off, correct.?

 

[brettp]

If that piece runs between 2 and 3 with no other ends open, leave as is.

 

[MisterCB750SCMoto]

Yes, but you need to cap the nipple on carb 2 (i think) that goes to that vacuum operated thing.
If your petcock is vacuum operated, that needs to be replaced, too. OR, you can connect the nipple on carb 2 to the vacuum line on the petcock. What petcock do you have? Pics, please.

 

[MisterCB750SCMoto]

Yes, but you need to cap the nipple on carb 2 (i think) that goes to that vacuum operated thing.
If your petcock is vacuum operated, that needs to be replaced, too. OR, you can connect the nipple on carb 2 to the vacuum line on the petcock. What petcock do you have? Pics, please.

Sorry for late reply.
All the petcock has is a spot to connect fuel line from petcock to carb. Last pic is the fuel inlet vacuum thingy. Ik there are vacuum things on the petcock but mine is not like that.

 

[brettp]

Your petcock is not vacuum operated. You can gravity fed straight to the fuel rail.

 

[MisterCB750SCMoto]

Your petcock is not vacuum operated. You can gravity fed straight to the fuel rail.

Do you know what this is for.? Is it an air vent.? Do I need to cap this off as well.?

 

[brettp]

I honestly can't remember what that is. I need a expert or two to weigh in. Or you can search the forum for "carb black nipple t". See what comes up.

 

[kirky]

i think that is for your breather pipe