Can I convert the Oil Tank on a Wave Venture to a "Reserve Fuel Tank"

[E350]

I wouldn't bother you guys and gals with this couch question but for some reason, pwctoday.com does not appear correctly on my computer.

I was given a 1996 Yamaha Wave Venture WVT700 (701 62t). I converted it to pre-mix only and did an oil pump injection delete with a blank cover from T.C. Freeride, kept the chokes but added a primer plunger and used the oil injection ports under the flame arrestors for primer ports into the carbs.

So, now the ski has an oil tank which will never be used.

The oil tank and the fuel tank each have electrical sensors which monitor the fuel and oil level.

Can I move the reserve line to the oil tank and use the old oil tank as a reserve fuel tank? Or are there safety or other concerns?

And my wife has an 1987? X2 which was long ago converted to premix. Could I do the same thing on the X2?

 

[Mike W]

I’ve seen people do this in the past. The one thing you have to figure out is getting the tank vented like the primary tank, as well is making sure the cap seals well enough not to let fuel or fumes to escape.

 

[E350]

@Mike W Well this thread was worth the price of posting. I eventually would have thought about installing a check valve to prevent a vacuum, but your post prevented my usual trial and error frustration.

I think that the oil tank cap is exactly the same as the fuel tank cap.

I will look at the oil filler cap to see if it is gasketed like the fuel filler cap.

 

[WFO Speedracer]

I have seen it done on 650SX and X2 before, you need to check and see if the cap is vented or not , you want it to be non vented with a one way valve on the tank

 

[Quinc]

Doesn't that ski have a 10 gallon fuel tank? I had a 62t waveraider and it seemed like one tank would last me multiple lake trips with friends riding it. Probably not worth the time for a couple extra gallons unless you are planning on some really long rides.

 

[E350]

1996 Wave Yamaha WV700:

Fuel tank capacity 13.2 gal.
Reserve 2.3 gal.
Oil tank capacity 1.0 gal.

The reason I was thinking of doing this was that I want to run the primer fuel pick up on its own tank port.

So, I could put either hook the primer up to the fuel "reserve" tank output port and make the oil tank the "reserve" fuel tank
or
hook the primer fuel pick up to the oil tank output port.

Dude, 13.2 gallons . . .

For comparison:

1995 FX1:

Fuel tank capacity 3.7 gal.
Reserve 0.95 gal. (but I disconnected the "reserve" and am using it for the primer fuel pick up)

 

[Baja 252]

I'm curious why you want to run the primer off of it's own dedicated line rather than just tee off the supply line?

 

[E350]

@Baja 252

On the 550sx, SN SJ and FX1 it went this way.
I installed primer pumps into each one of those skis.

I first hooked the primer input to the carb input fuel line.
There was air in the line occasionally.

Then I hooked the primer input up to the carb return fuel line.
There was air in the line always.

On the 550sx, SN SJ and FX1 I I disconnected the on/off/reserve selector, so I had an extra port to use.

WaveWarrior also deleted his on/off/reserve selector and he just caps his unused "reserve" port. If he runs out of gas, he can pull the fuel line off the on port and uncap the reserve port and put the fuel line on the unused reserve port and swap the cap to the "on" port.

I can do the same thing by pulling the fuel line off the "on" port and putting it on the reserve port, but until and unless that happens, I am using the reserve port for the primer input.

Now the Wave Venture is a different beast altogether. It has an "appendix." What I mean is that since I have converted it to premix, it now has a vestigial non-functional unused extra tank.

So, why not use it for either a dedicated reserve fuel tank or for a dedicated primer tank?

BTW, we rode today. I just went out to the SN SJ and FX1 on the trailer and looked at the carb input line (connected to the "on" port on the tank), and the primer input line (connected to the old reserve port on the tank), and the return line.

I am using orange translucent Fast Flow Fuel Line https://fuel-line.com/ so I can see the contents of each line.

The carb input line is solid with fuel.

The primer input line is solid with fuel.

The carb return line has air in it.

Ever since using a dedicated fuel tank port for the primers, the primers are a one pump and go deal. There is never any air in the lines.

So, this is just my personal experimentation and personal experience.

I am a newbee here, so my personal experience may be unusual. Your results may vary. And I would appreciate any suggestions. Better information never hurts my feelings.

 

[WFO Speedracer]

If you put a drop in the fuel line on the return line, let it go nearly to the bottom of the ski and put the primer fitting there, there will always be fuel there because fuel will not run uphill

 

[E350]

It occurs to me from looking at the schematic that I will not have a carb return line to the oil tank.
There is also no extra port to install a check valve in the oil tank.
The oil cap is not vented but without a check valve in the oil tank, it would suffer from a vacuum as the fuel is drawn.

So, passing on this idea. Thanks guys for helping me noodle through the idea.

 

[Baja 252]

If you put a drop in the fuel line on the return line, let it go nearly to the bottom of the ski and put the primer fitting there, there will always be fuel there because fuel will not run uphill

X2 This is what I've always done and it works on our SJ.

 

[WFO Speedracer]

#16 is a one way check valve just like the one on the fuel tank, any gravity feed system must be able to pull air in or there will be no flow, no there will be no return line.

 

[Pro-pulsion]

If you put a drop in the fuel line on the return line, let it go nearly to the bottom of the ski and put the primer fitting there, there will always be fuel there because fuel will not run uphill

^^ this. Never tap into the fuel supply hose for a primer. The primer could fail and pull air leaning your main supply or the T could crack or break doing that. Putting the T in the bottom of a big loop on the return line guarantees there will always be enough fuel for a good 7-8 primes and no compromise to the only supply you have.

I do like the dedicated tank for priming though. I think that's a brilliant idea to keep your original fuel system in tact with no cutting of hoses. Put a straight fitting on right at the base of the tank. There'll always be the gravity weight to help with keeping the line full....of course you'll need to reduce down to 1/8" off the tank as it uses a 1/4" spigot but that's an easy fix.

 

[mikidymac]

Keep in mind you would also have a 1 gallon stagnant tank that basically goes bad since you never use more than a couple oz priming.

 

[Quinc]

Fill it up with whiskey and put a little hose/straw up through the handlebars.

 

[Baja 252]

If your detrimined to do it, I wonder if you could turn it upside down like this, and convert a fuel tank vent to a small primer reservoir rather than using a gallon tank.

 

[WFO Speedracer]

If your detrimined to do it, I wonder if you could turn it upside down like this, and convert a fuel tank vent to a small primer reservoir rather than using a gallon tank.

View attachment 425736

There would be no way to vent that unless you loosen the cap, and that would be dangerous IMO as it would let gas fumes escape

 

[bored&stroked]

Doing that would mean the return for the carbs would have to force the gas back into the large tank basically under pressure from the weight of fuel pushing down?

 

[Baja 252]

I know the OP wasn't really asking about adding a second tank for extra capacity, but a few people have mentioned it, so I thought I'd post this.
We have 2 skis with a second fuel tank and people always ask how to do it. I drew up this diagram a few years back to show a friend how to do it.

 

[E350]

Ok I am pondering this. As long as I do what @WFO Speedracer said for my primer T using a bottom transfer line from the second tank to the original tank I could put the vent in the upper second formerly oil tank.

This would also take care of the stale fuel concern raised by @mikidymac

The downside would be that the ski wouldn't have a "reserve" tank, which I think could be important for a newbee couch rider friend. Because these sit downs are likely capable of skiing long distances.

I need to ponder more and examine the actual tanks again closely, but I think @Baja 252 may come in for the win!