Vented Gas Cap

[Popeye_5591]

If I go from gravity fed back to a fuel pump, do I have to put the vent plugs back into the gas cap?

[Brad_G]

I don't see any reason why you would. Just curious, most go from pump to gravity, why the reverse?

[Popeye_5591]

I had problems with my carborator and my fuel pump at the same time. I tried to remove the fuel pump and go gravity fed, but that incorporated a whole set of variables that interfered with troubleshooting my carb issue. I have to go back to the pump just until I get my carb right and then I'll attempt pumpless again. Which raises my question, do i have to put the plugs back in the cap just to take them out again in the near future? Will my bike run fine with a pump and a vented cap?

[Shores]

A vented cap will not interfere with the pump to your carburetor. It would be just like riding with no cap on the tank. I'm sure the plugs are there to prevent the spilling of fuel in the event of a crash. Stock tanks are vented through the rollover valve which is attached to the tubing that comes off the front of the tank and goes down to the bottom of the frame.

[Popeye_5591]

BTW, if anyone wants to see a great video on how to vent the cap, here it is...

https://youtu.be/dhoocw5K-aI

[Lug Nut]

Don't need to put the fuel pump on a diagnose a carb issue. Leave the tank vented, also recommend removing your rollover valve, removing the inlet screen on the elbow to the carburetor fuel line in, aftermarket fuel filter in line between petcock and carburetor, cut down tall petcock tube by 3/4 in. Tell us your year, miles, all modifications, everything you've done to the carburetor so far in terms of jetting, needle, float height setting etc. We can get you on the right track. But leave that fuel pump off.

[Brad_G]

I'm with Lug Nut on this, just leave it off and address the issues at hand. I appreciate you wanting to take that variable out of it but if your plan is to remove it again I think it's going to end up wasted effort.

I'm not a carb guru so maybe I overlooked your post describing the trouble your having (that you feel is carb related). As mentioned above, give us the info about the current carb setup and air intake/exhaust on your bike and what you're fighting. There's a great wealth of knowledge here and should be able to help you sort through things.

[Kurf]

Out of interest : I did remove the pump and followed all needed actions in regards of fuel flow but never heard of venting the gascap. Is it a must to get enough flow when pumpless?

[Shotround]

My tank vent is rusted shut. Thus requiring me to vent via fuel cap. Yes, mine is blocked at the tank, not at the rollover valve.

If there is a way to break it open that would give me a good excuse to get new tools.

[Lug Nut]

Out of interest : I did remove the pump and followed all needed actions in regards of fuel flow but never heard of venting the gascap. Is it a must to get enough flow when pumpless?

All needed actions includes typically venting the gas cap, eliminating the rollover valve, eliminating the screen filter going into the carburetor elbow, getting a good high flowing inline filter, new gas line, cutting down the taller petcock tube, lots of things. Unfortunately most the people out there seem to think you just take the fuel pump up and hook the fuel line to the carb and go. That's not how it works.

[Kurf]

Thanx: can you tell me about cutting down the petcock tube? Will this affect reserve?

[Duke]

NO. You do not need to vent the cap, but you do need to make sure your tank is venting.
I've done the venting of the gas cap, and I didn't like the fuel smells and fuel seeping out of the cap when the tank was full. Myself, I remove the rollover valve due to it failing. The rollover valve is a double acting check valve, and is very sensitive to any debris causing failure for it to work correctly. The only thing you should think about is the fact that fuel could leak out when the bike is on its side, and it would be the case with a vented cap too.

[Kurf]

Thanx: how do I remove the roll over valve?

[Duke]

Follow the tank vent tube to the down pipe of the frame, you will see a plastic part that has a in and out hose nipple on it. Remove that part and add a hose to hose connector to the hoses.

[Popeye_5591]

What did you do with the choke/enricher knob since the bracket is gone. Also did you guys use the metal gas line that is currently running between the cans or did you eliminate that.

[roadiemort]

Or you could leave the pump as Yamaha built it and just ride.

[Lug Nut]

What did you do with the choke/enricher knob since the bracket is gone. Also did you guys use the metal gas line that is currently running between the cans or did you eliminate that.

Vstar 650 choke cable with bracket (eBay $10) and use the bracket and mount as shown. Easy peasy

[Popeye_5591]

will that fit under the factory airbox?

[Popeye_5591]

My Carburetor issues are fixed and the bike is running great. My Bike is currently configured on the fuel pump. Now I'm going to move towards the gravity fed mod. I will keep you posted...

As Always, Thanks for your help

[Shores]

Thanx: how do I remove the roll over valve?

It's a small cylindrical plastic piece about the size of your thumb that is attached to some small black rubber tubing running down the front frame members. There might be two of them, there are two on my 2008. Just take it out and splice in another piece of small tubing. If it's not plugged, I would not remove it because it is a safety feature in the event the bike falls over.

[Lug Nut]

Popeye...No the whole use for the V-Star 650 bracket is the bottom hole for the stock air cleaner assembly. I cannot fathom going to all the work effort time expense that you have and then keep the factory air box. It's a huge restriction. Get yourself a nice round open element air cleaner, order the Baron's jet kit, jetted how we tell you to, do all the stuff you need to make it pumpless and you'll be happier than you are now. It will be faster more responsive smoother running and you'll never have to worry about being stranded due to having a fuel pump installed.

[Kurf]

What did you do with the choke/enricher knob since the bracket is gone. Also did you guys use the metal gas line that is currently running between the cans or did you eliminate that.

I have put the choke in place of the bottom airbox bolt like this:

[Kurf]

Regarding cutting 3/4 of the pipe : what difference will it make? Is it because you remove the top the flow will increase?
Cut just above the ridge?

[Duke]

Cutting the tube, will let fuel flow at a lower level in the tank while the Petcock is in the on position. You won't get any more measurable fuel flow. Fuel flow is controlled by engine fuel requirements needed, pulling fuel from the float bowl. The float, with the needle & seat, maintains the level in the fuel bowl and needs to have enough fuel flow, "volume", to be able to maintain this level in the bowl during all the fuel requirements.

[Duke]

Check this post out about the Petcock.

https://www.roadstarclinic.com/forum/roadstar-classifieds/bike-parts-for-sale/intake-fuel-systems/34217-petcock-with-fuel-filter

[Kurf]

Thanx Duke.
Any experience with use of a high flow pingel petcock?