2003 DRZ400S - Aqualine Tank

[mtntrails]

I recently installed a 28 litre Aqualine Safari tank on my 2003 DRZ400S. With appx. 1/2 - 1 gallon of fuel still visible in the tank, it spit, sputtered & died apparently (& ironically) from fuel starvation - luckily, I was just uphill from my house so it was no big deal. (OK, quit laughing)

So, the petcock sits lower than the incoming fuel line. After rolling it home, I put in ~1/2 gallon of fuel, but she still would not fire. After I put in 3 more gallons of gas, she fired right back up - so I'm guessing that there needs to be some substantial gravity there to feed the carb. It would be nice to be able to use more of that fuel capacity. Any ideas as to how to accomplish this? A small inline fuel pump, maybe? (is there such a thing for bikes?)

The reason I bought this massive tank in the first place was to have a 250+ mile range. It is a damn shame to have a 28 liter tank when only ~22-24 liters are useable.

Thanks in advance for your help.

[Bear on a bicycle]

Does your S still have the stock Mikuni carb? If so, you're probably suffering from lack of vacuum. On the stock tank/petcock, there are 2 lines connected, one for fuel & one for vacuum. Did your new safari tank come with a petcock or did you use the stocker? If you used the stocker, just hook the vacuum line back up & you should be good.

I've also read about new tanks needing to be washed out before using them due to small bits of plastic & what-not left over from the manufacturing process. It could be a clogged petcock.

Good luck!

Rick Peyton

[ekaphoto]

Try an aftermarket petcock, just be sure to plug the vaccume line that goes to the petcock. Also have you tried taking out the spacer on the stock petcock?

[moe sizlak]

interesting ... the safari tank i just installed had bits of plastic inside , they need a good wash out before fitting .

the stock petcock has one line only .

i thought the 17 litre looked big on my KLX , the 28 litre tank must look

[mtntrails]

Thanks for the replies.

Yeah, it's a big'n. Unfortunately, the next biggest tank available is the IMS 3.9 Gallon unit which would not fulfill the mission of a 250 mile fuel range.

My dealer installed the tank with the Aqualine petcock. I'll have them install the stock petcock w/ the vaccum line. While they are doing that, I'll have them splice in an in-line fuel filter.

[mtntrails]

another photo...

[mtntrails]

one more...

[viverrid]

Originally Posted by mtntrails

My dealer installed the tank with the Aqualine petcock. I'll have them install the stock petcock w/ the vaccum line. While they are doing that, I'll have them splice in an in-line fuel filter.

Holy smoke, that tank looks like it goes down WAY below where the bottom fuel could have enough "head" to reliably feed!

A DRZ has no fuel pump, it is gravity feed. The "vacuum petcock" only means an "automatic" petcock that closes unless some vacuum (form the running engine) is applied to its diaphram, and then it opens and allows fuel to flow.

Changing back to a vacuum petcock won't create a vacuum, nor will it pump or suck fuel uphill out of the tank.

I think it is common with some of the aftermarket enlarged tanks that the fuel on the right can't get to the fuel outlet on the left, unless the bike is tilted over to transfer the fuel.

[viverrid]

Originally Posted by Bear on a bicycle

Did your new safari tank come with a petcock or did you use the stocker? If you used the stocker, just hook the vacuum line back up & you should be good.

That has to be off the mark. If he still had the vaccum petcock (which turns out he doesn't), if the vaccum line wasn't hooked up, the bike would only have run 1 minute or so and then stalled (don't ask me how I know this) no matter how full the tank was (as long as the selector was on ON or RES).

On the "vacuum petcock", what the vacuum does is to pull the valve open so that fuel can flow. Otherwise it is normally closed. (So the rider doesn't have to turn it OFF when parked.) The three positions of the vacuum petcock are RES, ON and PRI which is Prime and bypasses the vaccum function so that you can fill the float bowl on a bike that has been serviced or otherwise sat without fuel. (There is no OFF position sicne it is 'normally off' without vacuum applied.)

Don't be encouraging people to misunderstand their vacuum petcocks!

(This is the most times I have ever said "petcock".)

[Young-gun-640]

I just so happen to have a spare (and unused) mikuni fuel pump that i used on a 28 litre tank for a ktm 620 LC4.... it runs off the vacuum created on the engine side of the carby... it works, anyone interested?

[Ned Flanders]

I've the DR650 with aqualine tank. I get the same problem when reserve cuts in. The problem, I think, is that a bubble of air lodges in the upside down "U" where the pipe meets the carb. This was discussed in TT DR thread.

One very good suggestion from a poster was to blow into the cap tube to pressurise the tank (then pinch the tube closed for a bit), which reestablishes the syphon effect from the carb.

I can't do the that anymore since I recently got a locking cap with no tube.

Someone else rotated the spigot on the carb (braver man than I), eliminating the "U".

[ChrisCrossed]

I have one of those tanks too and while I've only run it to reserve once I allways thought you'd have to get inventive to get all the fuel out of it.

Tipping the bike on the LHS is the first move to access the fuel on the right. Then running the front wheel up a bank to get the dead fuel from the front cavity to the rear would be next.

Otherwise you'd have to plumb a second petcock and a pump of some description. There would still be some fuel in the front that was inaccessible.

The tanks were initially designed for the Oz Safari - I think - and the niceties of twin taps and fuel pumps were not at the top of the priority list. Nor did the Australian market bikes have a vacuum petcock - we only ever got the full enduro models until recently. The good thing is at least the fuel is in there somewhere!

[mtntrails]

Thank you for all of this great insight. It's much appreciated.

So, in conclusion, the vaccum line to the OEM petcock really does not do anything to pump the fuel through the line(?). What I really need is a small fuel pump for that last 1/2-1 gallon of fuel to be able to feed in to the carb(?).

[BikePilot]

Correct, all that vacume line to the oem petcock does is make the petcock turn on and allow fuel to flow (assisted only by gravity) just exactly as yours does when you move it manually from "off" to "on".

If you were to buy that vacume operated fuel pump you could plumb it in the fuel line then use any vacume line to power it (the one that used to go to the petcock would be a natural choice).

PS, my DR250 with 4.25 gallon tank has a 250-300 mile range, wanna trade

[beefjerky]

Originally Posted by mtntrails

Thank you for all of this great insight. It's much appreciated.

So, in conclusion, the vaccum line to the OEM petcock really does not do anything to pump the fuel through the line(?). What I really need is a small fuel pump for that last 1/2-1 gallon of fuel to be able to feed in to the carb(?).

Should still be able to get 250 miles out of it even without what's left over in the right hand side portion.


When I was trail riding, it seemed to scavenge the last few drops a lot better than road riding. Slow down and pop a wheelie!