Premium Member keithu Posted March 15, 2020 Author Premium Member Share Posted March 15, 2020 It's time to start installing auxillary fuel. I have a four gallon RCI fuel cell that will be installed on the tail, feeding into the main tank via gravity feed. Today I drilled my tank and installed a bulkhead fitting. I emptied the main tank and let it air out for a week while I was away on business, and today I did the deed. When I did this years ago on my TT600 I taped a plastic salsa container inside the tank to collect metal shavings, but the FJ fuel pump hole is pretty small. I used a plastic tray and an old hard drive magnet to try to collect shavings, but I still had to spend a lot of time fishing shavings out of the tank with a magnet. Nothing says "Oh god what have I done" like punching through your fuel tank with a drill bit. I used JB Weld on the bulkhead fitting in my TT600 tank, but this time I just used some Permatex thread sealant and Locktite. We'll see how it holds up. Lily is skeptical about the whole thing. 3 2 Link to comment Share on other sites More sharing options...
BBB Posted March 15, 2020 Share Posted March 15, 2020 While you’re there @keithu, rip off the foam at the front edge of the tank underside. When I had my ECU flashed, it was one of the recommendations from the tuner as it allows better air flow into the airbox. Red 2015 Tracer, UK spec (well, it was until I started messing with it...) Link to comment Share on other sites More sharing options...
Premium Member keithu Posted March 15, 2020 Author Premium Member Share Posted March 15, 2020 5 hours ago, BBB said: While you’re there @keithu, rip off the foam at the front edge of the tank underside. When I had my ECU flashed, it was one of the recommendations from the tuner as it allows better air flow into the airbox. I question the benefit of that. Any slight gain in airflow might be offset by the resultant warmer fuel, reducing air/fuel mix density. Link to comment Share on other sites More sharing options...
Supporting Member texscottyd Posted March 15, 2020 Supporting Member Share Posted March 15, 2020 13 hours ago, keithu said: Lily is skeptical about the whole thing. Lily seems like a wise soul. Interesting project. I look forward to hearing the outcome. 1 Link to comment Share on other sites More sharing options...
Premium Member keithu Posted March 16, 2020 Author Premium Member Share Posted March 16, 2020 9 hours ago, texscottyd said: Lily seems like a wise soul. Interesting project. I look forward to hearing the outcome. She is. A bit of a setback: I installed the tank and put some fuel in it to test the seal on the bulkhead fitting. After ten minutes there was the slightest hint of fuel seeping through the seal. Any fuel leak is unacceptable, so it's back to the drawing board. I removed the fitting and cleaned up the hole. Plan B is to just JB Weld the bulkhead fitting. That will make it a permanent feature of the tank, but at least it won't leak. 1 Link to comment Share on other sites More sharing options...
BBB Posted March 16, 2020 Share Posted March 16, 2020 On 3/15/2020 at 2:04 PM, keithu said: I question the benefit of that. Any slight gain in airflow might be offset by the resultant warmer fuel, reducing air/fuel mix density. Warmer fuel due to removing that tiny bit of foam over the smallest section of the tank? I’m not sure there will be a significant change in the insulation effect from the engine. The stoichiometric mix of air/fuel is around 14:1 so any tiny changes in density of the fuel are outweighed by the air volume. And by the way, octane density only drops 8% from 20 celcius to 80 C, so that’s a 0.5% change when mixed with air at that ratio. 1 Red 2015 Tracer, UK spec (well, it was until I started messing with it...) Link to comment Share on other sites More sharing options...
duhs10 Posted March 17, 2020 Share Posted March 17, 2020 On 3/15/2020 at 10:04 AM, keithu said: I question the benefit of that. Any slight gain in airflow might be offset by the resultant warmer fuel, reducing air/fuel mix density. @2wheeldynoworksis who began advising owners that the removal of the foam was beneficial... they have the bikes on the dyno and I doubt he would make it up for $#!+$ and giggles. Regardless I actually like the increase in induction noise. 2 '15 FJ-09 w/ lots of extras... Fayetteville, GA, USA Link to comment Share on other sites More sharing options...
Premium Member keithu Posted March 17, 2020 Author Premium Member Share Posted March 17, 2020 I received my parts for the fuel cell rack. I decided to make the rack using T-slot aluminum tubing from 80/20. We use this stuff a lot at work, and it has an excellent strength-to-weight ratio. I can also make a complex structure without any welding. Here is the rack mocked up. I'm using the mount points for the OEM grab handles. 2 Link to comment Share on other sites More sharing options...
Premium Member keithu Posted March 17, 2020 Author Premium Member Share Posted March 17, 2020 I may add a flat aluminum gusset between the frame and the aft saddlebag bolt. Extra strength here can't hurt. Link to comment Share on other sites More sharing options...
Supporting Member betoney Posted March 17, 2020 Supporting Member Share Posted March 17, 2020 27 minutes ago, keithu said: I received my parts for the fuel cell rack. I decided to make the rack using T-slot aluminum tubing from 80/20. We use this stuff a lot at work, and it has an excellent strength-to-weight ratio. I can also make a complex structure without any welding. Here is the rack mocked up. I'm using the mount points for the OEM grab handles. Good job on the rack, looks great. What kind of range are you wanting/ hoping to achieve before refueling? 350-375? ***2015 Candy Red FJ-09*** Link to comment Share on other sites More sharing options...
Premium Member keithu Posted March 17, 2020 Author Premium Member Share Posted March 17, 2020 24 minutes ago, betoney said: Good job on the rack, looks great. What kind of range are you wanting/ hoping to achieve before refueling? 350-375? The goal is 300 miles before I need to think about it. Under normal conditions I should be able to go 350 miles, which is usually the max interval for IBA rides and most LD rallies. In a pinch I should be able to go 400 miles, or even a little more if I run it to fumes. 1 Link to comment Share on other sites More sharing options...
BBB Posted March 17, 2020 Share Posted March 17, 2020 That T-slot aluminium tubing looks excellent for framing. It must have a really good strength:weight ratio. What total mass are you adding when the fuel cell is full? Is there a way to bring the mass forward, so that it is more over the rear seat or are you using that area already? I was thinking that a more mid point for the centre of gravity would aid stability. 1 Red 2015 Tracer, UK spec (well, it was until I started messing with it...) Link to comment Share on other sites More sharing options...
Dodgy Knees Posted March 17, 2020 Share Posted March 17, 2020 That could make for some interesting handling... 1 Link to comment Share on other sites More sharing options...
Premium Member keithu Posted March 17, 2020 Author Premium Member Share Posted March 17, 2020 8 hours ago, BBB said: That T-slot aluminium tubing looks excellent for framing. It must have a really good strength:weight ratio. What total mass are you adding when the fuel cell is full? Is there a way to bring the mass forward, so that it is more over the rear seat or are you using that area already? I was thinking that a more mid point for the centre of gravity would aid stability. I want to use the space in front of the fuel cell for a water jug and other storage, hence I positioned the frame further aft. The frame (~5 lbs), tank (7 lbs), and four gallons of fuel (24 lbs) only adds 36 lbs (16kg) total to the rear of the bike. That's way less than any human passenger. It should have no more effect on handling than, say, a loaded top box. Probably less, actually, since top boxes are usually mounted even higher and further aft. Edit: I looked up top cases. A 46L Givi trunk (which many people seem to use) weighs 10 lbs, and has a rated capacity of 22 lbs. The mounting rack probably weighs at least four lbs, so this common luggage setup weighs at least as much as my fuel cell but is carried higher and further back. And of course we know nobody ever exceeds the weight rating of their trunk, right? 😀 2 Link to comment Share on other sites More sharing options...
angusmcoz Posted March 17, 2020 Share Posted March 17, 2020 Just curious, does that fuel cell have internal baffles to prevent the fuel sloshing side to side? Link to comment Share on other sites More sharing options...
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