Auxilliary Fuel on Gen2?

[Pete]

Hi all,

As you may recall I've been making some Tanji style cells. [now that I have finished more than Tanji did maybe we could call them something else--but that is not the reason for my post ]

Based on a rider's experience with my last cell build it seems a fuel pump may not be needed on the Gen2 FJR. Before I start telling folks they can opt out on that option I'd like to get the WOTL.

I know almost everybody ended up with a pump on the Gen1 bike.

Here are some of my questions:

Do you think the Gen2 is different from the Gen1?

Is this guy's bike an anomaly?

Is the cell I built for him an anomaly?

I'd sure like to not have the pump. Not only is it better from the aspect of one less item to fail but it is easier (and less expensive) to make.

thanks for your assistance and best regards,

 

[dcarver]

I'd sure like to not have the pump. Not only is it better from the aspect of one less item to fail but it is easier (and less expensive) to make.

I have TAT tank - slightly different build than Tanji style, e.g. perhaps a bit higher? It flows OK with gravity, but added a valve and a squeeze bulb pressurize the air gap and force a faster main tank feed. I like to drain the aux tank completely so I know more precisely via the fuel gauge in the main tank just how much I have left. I vote to keep the fuel pump on.. If I get one of your tanks it will be 'powered'..

All my aux tank info here.

 

[RiderX]

I am the rider Pete is referring to that hasn't used the pump too much.

I think the Tanji Style should now be the IBPete style since he's made a bunch of them

Although TS has a nice ring.

Sorry for repeating data on the LD list, but I keep the valve open all the time and have one big fuel tank. Only caveat is that with the IBPETE style (low waterline), the fuel will run out of the main tank if you're at a low fuel state and sitting at an incline (don't ask me how I know :blink: ) So what I've done the past dozen are so complete fill ups: I keep the valve open when full. It stays open until three bars (I know the 4.5 gallon IBPete style tank is empty). Valve gets closed at three bar (or if you forget two bar or one bar). Now I'm incline proof and don't have to worry.

Of course I also have the pump installed and it did bail me out once when I kept the valve open with low state on a slight incline. I learn slow.

Anybody else have this style tank with no pump? I know the more upright tanks wouldn't have as much "reverse flow" potential and probably little downside to gravity feed.

 

[dcarver]

What ID diameter valve, filter, hosing are you using?

 

[Pete]

What ID diameter valve, filter, hosing are you using?

I use 1/4" hose. but before everybody says "there's the problem" I have taken that into consideration. Everybody says 5/16" (8mm) but...

the best flow you can get is thru the smallest opening and I've found that most 5/16 hose barbs only have a .220" opening and most 1/4" barbs have a .180" opening so the differnce isn't really 1/16". I use 1/4" because it routes more easily and costs less overall. Additionally, as long as the flow rate is faster than you are burning it, larger hose only lets you see the gauge come up faster.

I will confess that the first 5 cells used this cute little Hoke toggle valve. I scored them off of ebay at a really good price and it really is a nice valve. When I started looking to get more of them I discovered that they are really expensive ($80) and have a low flow rate (.4 factor). I have gone to a full flow valve. It's not as cute but costs <$8.

Josh's bike has the full flow valve and that may be why he is getting better results. I have had some offline comments that indicate some folks do okay with gravity and some don't. It seems like a crap shoot on when and where the bike came out of the assembly process.

So far it seems like the concensus is that you can't go wrong with a pump and the piece of mind is worth the extra expense.

Please keep the comments coming they are most helpful.

Best regards,

Mike

 

[RiderX]

Hey "Pete"

Was thinking about some differences and being that mine is a California model, it is vented differently (through hose to carbon canister vice gas cap). It is possible that of all the PITA I have with the "c" suffix (when removing fairings) there is a small benefit?

Brainstorming. . .

 

[SkooterG]

Hey "Pete"

Was thinking about some differences and being that mine is a California model, it is vented differently (through hose to carbon canister vice gas cap). It is possible that of all the PITA I have with the "c" suffix (when removing fairings) there is a small benefit?

Brainstorming. . .

As far as I know yours vents through the cap just like every other FJR out there. It's AFTER passing through the cap that it then routes to the charcoal cannister.

Have you ridden with the cell in REALLY hot weather? Like 100 degress +?

That is where there seems to be problems with any gravity cell with the cap not venting, pressure building up in the main tank, and then pushing fuel from main tank back to cell.

 

[RiderX]

Yes, about half has been over 100. Couple thousand miles 106-108. No issues.

I'm 43.7% sure it doesn't vent through cap. That defeats the purpose of the canister (can't vent directly to the precious planet).

 

[SkooterG]

Yes, about half has been over 100. Couple thousand miles 106-108. No issues.

Interesting. This is where most FJRs have the trouble. Doesn't matter type/maker of fuel cell. I personally only know of Gen Is. Perhaps it is a difference between Gen I and Gen II here.

I'm 43.7% sure it doesn't vent through cap. That defeats the purpose of the canister (can't vent directly to the precious planet).

I'm 98.37% sure it does. But I am have been wrong before.

At the cap there are two 'paths'. One is vent, one is overflow. Both go to outside bottom of tank via two internal tubes from the cap. On Cali models the 'vent' is then routed to the cannister with a rubber hose.

In fact I just looked at the Yammie parts diagram online and now I am 100% positive it works as I describe above.

I just compared the part #s on the cap assembly between Gen I and Gen II and they are the same. However interestingly, at some point Yamaha superseded the part number with a slightly different one. They obviously made some change. I might have to get one of the new part number fuel cap assemblies and try that. In the temps you describe, I get main tank pressurization eventually where it then flows backwards 100% of the time.

 

[RiderX]

We are both 100% on the parts fiche. I didn't / don't think air was allowed to be in contact with the fuel, thus convinced myself air only comes in through canister. Not sure what's appending on other end of rubber hose. Maybe one of our techs can pipe in.

Just picked up Georgia and Virginia Tour of Honor points and still haven't needed pump (not complaining )

Only time it's been hesitant is when I let a pressure differential develop: keep aux alve closed while main is sucking for like half a tank.

If instead it is open with both tanks full and closed off when empty, no issues. At three bars remaining, aux tank is always dry.

 

[Peter Murray]

Yes, about half has been over 100. Couple thousand miles 106-108. No issues.

Interesting. This is where most FJRs have the trouble. Doesn't matter type/maker of fuel cell. I personally only know of Gen Is. Perhaps it is a difference between Gen I and Gen II here.

I'm 43.7% sure it doesn't vent through cap. That defeats the purpose of the canister (can't vent directly to the precious planet).

I'm 98.37% sure it does. But I am have been wrong before.

At the cap there are two 'paths'. One is vent, one is overflow. Both go to outside bottom of tank via two internal tubes from the cap. On Cali models the 'vent' is then routed to the cannister with a rubber hose.

In fact I just looked at the Yammie parts diagram online and now I am 100% positive it works as I describe above.

I just compared the part #s on the cap assembly between Gen I and Gen II and they are the same. However interestingly, at some point Yamaha superseded the part number with a slightly different one. They obviously made some change. I might have to get one of the new part number fuel cap assemblies and try that. In the temps you describe, I get main tank pressurization eventually where it then flows backwards 100% of the time.

Scoot ,

I like others just removed the ball and spring and never had a problem with head pressure. My cell was gravity feed, also did away with the QD to improve flow. The only drawback is you can over fill the main tank and gas will puke all over the rear of the bike. Backflow is almost as bad as overfill.

 

[mferriter]

At the risk of hijacking this thread:

Does anyone carry a fuel container on their bike? I have one of the aluminum 33 oz cooking fuel bottles from MSR, but wondering if anyone has anything bigger or better. The MSR one is great - no detectable leaks, but the capacity is the main issue. 33 oz would only get me about 10 miles or so in a pinch.

It would be nice to have a flat rectangular leakproof container that could fit in the sidebags and hold a gallon or so. Of course I could just get 3 more of the MSR bottles.

 

[SkooterG]

Scoot ,

I like others just removed the ball and spring and never had a problem with head pressure. My cell was gravity feed, also did away with the QD to improve flow. The only drawback is you can over fill the main tank and gas will puke all over the rear of the bike. Backflow is almost as bad as overfill.

Yeah, I may be headed that way but would rather not. It is there for a reason.

So far, seems the Gen II FJRs don't really have this issue. Right now I am of the inclination to believe that Yamaha fixed this issue with the superseded fuel tank cap. Now, am I willing to pony of the $$$ to try one and test my theory? Or just pull the spring and ball?

 

[Peter Murray]

Scoot ,

I like others just removed the ball and spring and never had a problem with head pressure. My cell was gravity feed, also did away with the QD to improve flow. The only drawback is you can over fill the main tank and gas will puke all over the rear of the bike. Backflow is almost as bad as overfill.

Yeah, I may be headed that way but would rather not. It is there for a reason.

So far, seems the Gen II FJRs don't really have this issue. Right now I am of the inclination to believe that Yamaha fixed this issue with the superseded fuel tank cap. Now, am I willing to pony of the $$$ to try one and test my theory? Or just pull the spring and ball?

Just do it . Aside from the grimy mess with overfill of the main tank. Perhaps the only issue would be a loose rear with fuel on the tire. Head pressure issue resolved.

Best

PM

 

[SkooterG]

Scoot ,

I like others just removed the ball and spring and never had a problem with head pressure. My cell was gravity feed, also did away with the QD to improve flow. The only drawback is you can over fill the main tank and gas will puke all over the rear of the bike. Backflow is almost as bad as overfill.

Yeah, I may be headed that way but would rather not. It is there for a reason.

So far, seems the Gen II FJRs don't really have this issue. Right now I am of the inclination to believe that Yamaha fixed this issue with the superseded fuel tank cap. Now, am I willing to pony of the $$$ to try one and test my theory? Or just pull the spring and ball?

Just do it . Aside from the grimy mess with overfill of the main tank. Perhaps the only issue would be a loose rear with fuel on the tire. Head pressure issue resolved.

Best

PM

Or lots of ignitable fuel spilling all over me as I lay trapped under my FJR that just fell down on me.

Hey, it could happen!

 

[RadioHowie]

Scoot ,

I like others just removed the ball and spring and never had a problem with head pressure. My cell was gravity feed, also did away with the QD to improve flow. The only drawback is you can over fill the main tank and gas will puke all over the rear of the bike. Backflow is almost as bad as overfill.

Yeah, I may be headed that way but would rather not. It is there for a reason.

So far, seems the Gen II FJRs don't really have this issue. Right now I am of the inclination to believe that Yamaha fixed this issue with the superseded fuel tank cap. Now, am I willing to pony of the $$$ to try one and test my theory? Or just pull the spring and ball?

Just do it . Aside from the grimy mess with overfill of the main tank. Perhaps the only issue would be a loose rear with fuel on the tire. Head pressure issue resolved.

Best

PM

Or lots of ignitable fuel spilling all over me as I lay trapped under my FJR that just fell down on me AGAIN.

Hey, it could happen!

Completed the statement for ya!

 

[dcarver]

Scoot ,

I like others just removed the ball and spring and never had a problem with head pressure. My cell was gravity feed, also did away with the QD to improve flow. The only drawback is you can over fill the main tank and gas will puke all over the rear of the bike. Backflow is almost as bad as overfill.

Yeah, I may be headed that way but would rather not. It is there for a reason.

So far, seems the Gen II FJRs don't really have this issue. Right now I am of the inclination to believe that Yamaha fixed this issue with the superseded fuel tank cap. Now, am I willing to pony of the $$ to try one and test my theory? Or just pull the spring and ball?

:rofl:

Just do it . Aside from the grimy mess with overfill of the main tank. Perhaps the only issue would be a loose rear with fuel on the tire. Head pressure issue resolved.

Best

PM

Or lots of ignitable fuel spilling all over me as I lay trapped under my FJR that just fell down on me AGAIN.

Hey, it could happen!

Completed the statement for ya!

 

[SkooterG]

Scoot ,

I like others just removed the ball and spring and never had a problem with head pressure. My cell was gravity feed, also did away with the QD to improve flow. The only drawback is you can over fill the main tank and gas will puke all over the rear of the bike. Backflow is almost as bad as overfill.

Yeah, I may be headed that way but would rather not. It is there for a reason.

So far, seems the Gen II FJRs don't really have this issue. Right now I am of the inclination to believe that Yamaha fixed this issue with the superseded fuel tank cap. Now, am I willing to pony of the $$ to try one and test my theory? Or just pull the spring and ball?

:rofl:

Just do it . Aside from the grimy mess with overfill of the main tank. Perhaps the only issue would be a loose rear with fuel on the tire. Head pressure issue resolved.

Best

PM

Or lots of ignitable fuel spilling all over me as I lay trapped under my FJR that just fell down on me AGAIN.

Hey, it could happen!

Completed the statement for ya!

WTF kind of quote was that?!?! Lay off the booze Carver!

 

[Peter Murray]

Scoot ,

I like others just removed the ball and spring and never had a problem with head pressure. My cell was gravity feed, also did away with the QD to improve flow. The only drawback is you can over fill the main tank and gas will puke all over the rear of the bike. Backflow is almost as bad as overfill.

Yeah, I may be headed that way but would rather not. It is there for a reason.

So far, seems the Gen II FJRs don't really have this issue. Right now I am of the inclination to believe that Yamaha fixed this issue with the superseded fuel tank cap. Now, am I willing to pony of the $$$ to try one and test my theory? Or just pull the spring and ball?

Just do it . Aside from the grimy mess with overfill of the main tank. Perhaps the only issue would be a loose rear with fuel on the tire. Head pressure issue resolved.

Best

PM

Or lots of ignitable fuel spilling all over me as I lay trapped under my FJR that just fell down on me.

Hey, it could happen!

Ouch ! Did not cross my mind.

Perhaps that overflow line would need to be routed to the rear of the bike.