So we've all heard/seen the 650 xchallenge...let's see your XCOUNTRY!

[jtw000]

I used the same tank. I don't think it's going to work with the purple hose. The seal to the breather is absolutely critical. It needs to be so tight you can barely get it on and then sealed down with a clip. I had to switch to a rubber fuel line (honda I think) and drill a larger hole into the cap to take it (smaller internal diameter).
If the hose it easy to fit it won't suck. Once you get it right it will drain the secondary tank first every time, hassle free.
I gotta ask, what paint did you use? My tank is filthy and I would love to paint it black but the plastic resists chemicals.

[donnh]

Originally Posted by FinnDuro

You are doing it a bit wrong, yes. :)
That purple fuel line should reach uninterrupted to the inside bottom of that aux tank, one way or another. Either by somehow installing an external fuel line feed/tap to the bottom, or by somehow extending the fuel line also from the inside of that aux tank gas cap. In any event, you need to find a way to have that purple fuel line reach to the inside bottom of that aux tank, without any air gaps in between for the suction to work.

Thanks Fin, I should have shown the hose routing through the cap. Yes, it goes to the bottom of the Aux tank. The ACERBIS siphon system provides a cap with a through hole that the hose goes through. Following advice here I used a piece of copper wire to hold the fuel line rigid so it goes to the bottom of the tank. It's a little hard to see but the cap also has a vent hole where I placed a standard dirt bike cap.

After my last post I went back and using a new piece of hose and manually applying a vacuum I found out that the "vent" hose only let's air go one direction - out of the tank.

A little more research and I came to this ADV link: http://advrider.com/forums/showthrea...=392305&page=8 Which absolutely did not answer the question but was educational on how the BMW emissions system works and it was one of the most heated discussions I have ever witnessed on ADV

[donnh]

Originally Posted by jtw000

I used the same tank. I don't think it's going to work with the purple hose. The seal to the breather is absolutely critical. It needs to be so tight you can barely get it on and then sealed down with a clip. I had to switch to a rubber fuel line (honda I think) and drill a larger hole into the cap to take it (smaller internal diameter).
If the hose it easy to fit it won't suck. Once you get it right it will drain the secondary tank first every time, hassle free.
I gotta ask, what paint did you use? My tank is filthy and I would love to paint it black but the plastic resists chemicals.

jtw, so that is where you connected to the tank? I'm going the right direction? The line is sorta tight and I did use the cheezy clip type clamp that came with the tank so it may not be ideal. So your saying that air is leaking in around the hose and breaking the vacuum? Hmmm, could be. With the larger hole in the cap did the rubber part on the inside of the cap still work ok? I wonder if a fuel line from an automotive supply place would work?

Also following advice here I removed the breather assembly and took out some inner parts that I thought was the tip over valve.

I'll try to go out and take a few more pictures before I run into work.

[donnh]

Originally Posted by jtw000

I used the same tank. I don't think it's going to work with the purple hose. The seal to the breather is absolutely critical. It needs to be so tight you can barely get it on and then sealed down with a clip. I had to switch to a rubber fuel line (honda I think) and drill a larger hole into the cap to take it (smaller internal diameter).
If the hose it easy to fit it won't suck. Once you get it right it will drain the secondary tank first every time, hassle free.
I gotta ask, what paint did you use? My tank is filthy and I would love to paint it black but the plastic resists chemicals.

Oh, forgot to answer about the paint. I found some rattle can primer at Home Depot that said it worked on plastic, two coats with plenty of drying time in between. Second some automotive type rattle can flat black paint, a few coats with long drying time. A little came off during assembly but it seems to be holding. I am worried about pealing if some gas drips on it and sure enough when filling the tank for the first time I dribbled onto the tank and it just evaporated without removing the paint. Still, I'm concerned how long it's really going to stay black. I'll get the paint type in the next reply.

[tbarstow]

Originally Posted by donnh

jtw, so that is where you connected to the tank? I'm going the right direction? The line is sorta tight and I did use the cheezy clip type clamp that came with the tank so it may not be ideal. So your saying that air is leaking in around the hose and breaking the vacuum? Hmmm, could be. With the larger hole in the cap did the rubber part on the inside of the cap still work ok? I wonder if a fuel line from an automotive supply place would work?

Also following advice here I removed the breather assembly and took out some inner parts that I thought was the tip over valve.

I'll try to go out and take a few more pictures before I run into work.

I'm running the same setup on my XChallenge right now. I'm thinking one of 3 things: You have a vacuum leak, the breather vent doesn't work, or you are collapsing the fuel hose. What happened to the original piece of hose that came with your tank?

I have found the the little breather vents don't work for this application, just run a long piece of hose from the aux tank breather vent to the original vent hose and couple them together.

[uxc]

one more,

[donnh]

Ok, instead of getting to work at a reasonable hour I was out in the shop playing around with this...I opened up the vent hole on the ACERBIS tank to let more air in and I installed a better clamp on the top of the main tank. I'm using the purple hose until I have a chance to buy something different but it's nice because I can see if any fuel is flowing through it. I took off the vent assembly on the tank and verified it was free flowing - it is. I ran the bike for about a half hour and there is evidence of drips of fuel going from the aux tank into the main tank. I suppose at idle not much fuel is flowing and I shouldn't expect to see much fuel flowing between the tanks. The real test will be to go for a ride but we are having typical NW crappy weather today so I'll try to get a test ride in tomorrow.


I took a bunch of pictures here: http://donnh.smugmug.com/Motorcycles...3295423_Z3T3Pc

Here is the paint I used:

[wallywv]

uxc-- always a delight to see your photos.

[jtw000]

Originally Posted by donnh

Ok, instead of getting to work at a reasonable hour I was out in the shop playing around with this...I opened up the vent hole on the ACERBIS tank to let more air in and I installed a better clamp on the top of the main tank. I'm using the purple hose until I have a chance to buy something different but it's nice because I can see if any fuel is flowing through it. I took off the vent assembly on the tank and verified it was free flowing - it is. I ran the bike for about a half hour and there is evidence of drips of fuel going from the aux tank into the main tank. I suppose at idle not much fuel is flowing and I shouldn't expect to see much fuel flowing between the tanks. The real test will be to go for a ride but we are having typical NW crappy weather today so I'll try to get a test ride in tomorrow.


I took a bunch of pictures here: http://donnh.smugmug.com/Motorcycles...3295423_Z3T3Pc

Here is the paint I used:

Cheers for the reply. Think of the syphon system running like a drinking straw. The suck end is not critical at all, you could put it in a bucket of fuel and it will work. It's the other end that's critical. It has to be down really, really tight. I can't stress that enough. To get mine to work I had to have a hose I forced on with pliers (carefully, don't break the end cap). Then I clipped it down with the thing that came with the clip but get creative by all means. If you have a better way to lock that tube down then go for it.
Also think about putting petroleum jelly around the nozzle to seal it (vaseline). That will help and make it easier to get on. Be absolutely sure that connection is so tight you can't move it by hand and it will work. No question, mine did and I fitted it to the front with 2 metres of hose. You're absolutely spot on with everything else. It's just that seal, it has to be really tight. As I said, it's a drinking straw so think of it that way, it behaves the same.

And now on to the paint.

Cheers for the reply but rattle can paint probably won't stay on very well. I'm actually in the 3rd world now and supply is tricky but if you can get it then track down Simoniz Toughblack. It's awesome stuff, formulated for forklifts and heavy industry. I can't get it out here but it's 100% petrol resistant and goes on easy too. You will need a primer though, it will eat plastic. I'm not sure what primer you'll need to use, the plastic these tanks are made of is resistant to chemicals, I'm not sure paint will stick very easily.

[jtw000]

As you can see, I used very tight hose. I believe it was Honda fuel line but anything that is really tight will do. I couldn't get it to work with the purple hose either.



And here was the mounting point. As you can see it was a long piece of hose. Didn't make any difference.

[donnh]

After opening the venting a little and making sure the clamp on the tank was secure I managed to get out for a 25 mile ride between rain storms and noticed it drained about 1/3 of the gas from the aux tank. I still have the clear hose because I haven't had time to get a better one but will probably do that soon. I thought I would see fuel flowing through the tube as the bike ran but most times when I looked at the hose when stopped at lights it was empty. I have a theory why that is...... a certain amount of pressure differential (vacuum) needs to be present to draw fuel from the aux tank. As the main tank drains it starts building up a vacuum in the tank, that pressure differential will continue to increase until it reaches the point where it is greater than the amount necessary to draw fuel from the aux tank. When it reaches that point i suspect there is a big "gulp" and fuel flows from the aux tank to the main tank until the pressure is equalized and the whole cycle starts over. That would be why I observed that fuel is draining from the aux tank but unless I happen to see the "gulp" the hose is empty.

I think I'm considering this project done. Thanks to everyone for the suggestions and help

[donnh]

I'm posting this for the record in case anyone is searching for information on this topic. My Xc had the same cold stalling issue everyone here has discussed. I never had time to look into it and decided I would probably just live with it. Then as part of the aux tank install I removed the vent assembly from the main tank and removed the parts that have been described as the tip over valve. Ever since then the stalling problem has gone away.

Assembly with the insides removed


The parts just snap out and can be saved and re-installed later if needed. I really have no idea why this helped but it did. Hope this helps someone.

[donnh]

Originally Posted by jtw000

As you can see, I used very tight hose. I believe it was Honda fuel line but anything that is really tight will do. I couldn't get it to work with the purple hose either.

jtw, thanks for posting the pictures and the help. How far can you go with the extra 1.3g? I'm hoping to get to 200 miles. I can't help but notice the proximity of the fuel tank and filler cap to the exhaust pipe. You haven't blown up yet so I suppose it's OK but still.....

[jtw000]

My pleasure. In London I got an easy 200 miles, same all round Europe. I'm talking 200 miles before the warning light came on and gives you around 30 miles reserve (that's my bike, please don't get stranded for listening to my advice.) Across the middle east the fuel quality varied so much I just wouldn't like to say. In Iran there were days when I couldn't get out of forth gear due to total lack of power and obviously my mileage was lousy. With decent fuel and half sensible riding you should hit your target (I have the 5l version, I presume you have the same?)
The only issue I had was my own stupidity... My fuel line got cut (don't ask) so I had to replace it on the road. It worked mostly but in the heat of the afternoon in the desert it stopped sucking. Then as it cooled it sucked fine. Another example of the fact it needs to be good quality rubber hose down tight. I used scooter fuel hose (transparent) and it didn't work.
If you want to be really, really clever then drill a small hole in the bottom and fit a liquid sensor and wire it up to a light on the dash. Then you know when your tank is dry. Personally, once you fit the right hose you'll very quickly learn to trust the setup, it works fine. Then you won't need to worry and that's what this kind of little bike is all about. (Just my opinion.) As for the heat, that exhaust tucks in a lot closer to the main tank round the back. No, I had no issues. Even after a long run the tank was never hot to the touch.
I'm really loving the black look. Mine is really dirty now and could use a refresher. Sadly I can't fit mine at the rear, it snags on my rack. I like it at the front, I had it on the side over the middle east but now I'm going to fit it diagonally. It will make sense when you see it.

Here's the Middle East mounting. Perfect position but the mounting was difficult and too complicated

[leafman60]

Originally Posted by donnh

I'm posting this for the record in case anyone is searching for information on this topic. My Xc had the same cold stalling issue everyone here has discussed. I never had time to look into it and decided I would probably just live with it. Then as part of the aux tank install I removed the vent assembly from the main tank and removed the parts that have been described as the tip over valve. Ever since then the stalling problem has gone away.

Assembly with the insides removed


The parts just snap out and can be saved and re-installed later if needed. I really have no idea why this helped but it did. Hope this helps someone.

Yes, I recommended doing this when you add an aux tank. This little valve can cause problems. All the parts snap out. Don't over-tighten the screws when you re-install the plastic flange to the tank.