Can rain get into the tank via the fuel cap?

[Soliton]

I have had an issue where after long periods riding in the rain the bike will start to sputter and surge. I thought of course that it was an electrical issue. Recently however I did a 5000km ride and on quite a few occasions it rained. I never had a problem. The only difference was that I always had a tank bag covering the filler cap.

As an aside on the trip we saw a sign indicating 109km of twisty road. On the whole section of road we saw only 2 vehicles. I love riding in Oz. If any of you guys ever come here...NSW Delegate to Orbost (Towering Tree Fern forests straight out of the Jurassic.) Also the entirety of Tasmania and the Alpine Way. I rode with a mate who has a flash whizzer bike. It has more power and less weight (on paper) he was surprised that the "under powered, lumbering old man's behemoth" left him behind every time it got twisty. The joys of knowing your own bike, good suspension and a poo load of torque.

Anyhow...

Last week I got caught at a friends house when it started raining. The bike was out for about four hours in the pouring rain. The symptoms returned. When they are present they are intermittent and can go for days. The common feature is that when I leave the bike to sit for a while they go away and after riding it will return 10-15mins into a ride, then go away, then return (intermittent)

When the sputtering/surging starts it can be so strong that the bike becomes almost unrideable. I have to knee grip REALLY hard and rev the tripe out if it. I have water tortured the bike in the past to deal with some pre-ignition problems and it sounds exactly like that.

I have some new HT leads coming and I have been over the wiring but if it is simple thing like water in the fuel then that is easily dealt with. I live in a city that has the least rain of any capital city in Australia but I still want to work out what the issue is. My bike treats me very well and I hate not trusting it.

Any ideas?

[maccraith]

I have had an issue where after long periods riding in the rain the bike will start to sputter and surge. I thought of course that it was an electrical issue. Recently however I did a 5000km ride and on quite a few occasions it rained. I never had a problem. The only difference was that I always had a tank bag covering the filler cap.

As an aside on the trip we saw a sign indicating 109km of twisty road. On the whole section of road we saw only 2 vehicles. I love riding in Oz. If any of you guys ever come here...NSW Delegate to Orbost (Towering Tree Fern forests straight out of the Jurassic.) Also the entirety of Tasmania and the Alpine Way. I rode with a mate who has a flash whizzer bike. It has more power and less weight (on paper) he was surprised that the "under powered, lumbering old man's behemoth" left him behind every time it got twisty. The joys of knowing your own bike, good suspension and a ----- load of torque.

Anyhow...

Last week I got caught at a friends house when it started raining. The bike was out for about four hours in the pouring rain. The symptoms returned. When they are present they are intermittent and can go for days. The common feature is that when I leave the bike to sit for a while they go away and after riding it will return 10-15mins into a ride, then go away, then return (intermittent)

When the sputtering/surging starts it can be so strong that the bike becomes almost unrideable. I have to knee grip REALLY hard and rev the tripe out if it. I have water tortured the bike in the past to deal with some pre-ignition problems and it sounds exactly like that.

I have some new HT leads coming and I have been over the wiring but if it is simple thing like water in the fuel then that is easily dealt with. I live in a city that has the least rain of any capital city in Australia but I still want to work out what the issue is. My bike treats me very well and I hate not trusting it.

Any ideas?

I had very similar problems riding in the rain - shaking, sputtering, balking. However, mine eventually resulted in a stall and no-start. When I got it home, I went though everything electrical and fuel related thing I could think of. I even traded out the ignition coil. No joy. Finally found the problem in the cable that goes from the Hall generator up to the computer. The cable sheath had begun crumbling in certain areas, let the moisture in, shorted out the wiring and eventually corroded the wire so badly that it parted. Hence, no start, no spark, nothing! But before that it was doing what you described. Many others have had the same problem. To find it, you have to dismount the Hall generator behind the lower pulley in the front of the engine, THEN DISCONNECT THE CABLE AND INSPECT IT CAREFULLY. I went right passed the problem three times before I found it - in the cable about 6 or 8 inches up from where it connected to the magnets in the Hall generator. There are plans for DIY replacing of the cabling. But believe me, it is one heck of lot easier just to buy the whole assembly new. I bought mine in the U.S. at Euro moto Electrics http://www.euromotoelectrics.com
Good people; good prices. Good Luck!

[kirby]

When I read your question I thought I would tell you that I have done allot of ridding in the rain + let it sit out side uncovered in down pours and have never had a problem, and to answer the question I don't believe there is any way that water can get past a properly closed cap.
Then I saw the post about the hall sensor cable..ha! That was what I was going to suggest. That cable is notorious for damage from heat cracking! (+chaffing) I think that the after market one(s) are much better than the factory one (however I believe the BMW folks have upgraded the replacement ones.)

I have ridden all over OZ and Tas! Really like to ride from Sydney down thru the park to the snowies!

Cheers,
mike

[P_Jensen]

You may be correct in that the problem is water getting into the tank, but it may not be from the cap itself instead it may be that water is getting in around the filler cap assembly. Looking at the parts fiche for the R1150R filler assembly, there is a large o-ring around the filler assembly (Part #4 pictured in the link) which may not be sealing as well as it should. http://www.maxbmwmotorcycles.com/fiche/ ... d=04282014
For the $10.00 in parts it may be worth replacing both of the gaskets on the filler (#3 & #4) to see if the problem goes away.
On the R1200R models many people are adding a gasket from the S1000RR between the fillerneck and the tank to keep water from entering the tank. See the link for a better descripition
http://www.r1200rforum.com/forum/bmw-r1 ... over-2481/

Good luck

[sstein]

After reading this post, I was thinking that if water was getting into the tank ie getting into the fuel, the problem should persist until that tank of fuel is finished and the tank is refilled. I don't really know about fuel + water chemistry, but if the timing of the issue is unrelated to refueling, seems like it would be something else.

[peels]

not sure if it was answered, didn't see it...

but the overflow hose may be plugged, as mine was.

The cap itself, has a good seal. BUT. when you open the cap to fill the tank the next time, any standing water still in there can rush into the tank. This happened to me. I watched it, and made me sad LOL My 2 boys had washed my bike for me, and I didn't know about that particular issue.

EDIT:

found that GREAT thread where its covered quite nicely. clean that hole with small wire, or weed trimmer line, then blow it out.

http://r1150r.org/board/viewtopic.php?f ... ow#p234462

[Soliton]

Gee whiz,

So many things to check.

1 - I had no idea there was a water drain hole. I looked and you could never have picked it. The drain was clogged up with so much scunge as to be invisible. I have cleared it and blown backwards through the rubber pipe and air is now moving through it.

2 - I will check the seals to see that they are all functioning properly, and maybe replace them.

3 - I have new HT leads on the way.

4 - A new HE Sensor is a bit of an investment but a guy in Romania called Cata Dan has an OEM version that is fully waterproof. He rebuilt my throttle body and did a really good job go it so I reckon he's trustworthy.

5- The fuel change thing is a bit of a conundrum. I use fuel with 10% ethanol. This should absorb water ...eventually. This would seem to be complicated by issues of how much water got in. (If this is the issue). How much might be in the left hand lobe of the tank. Does the water start sloshing around when the bike gets going. Does it settle when you stand still / park. I ran the tank to 1 litre left in it and then refilled since then I have had only 1 incidence of milf stuttering and then nothing.

Thanks for the help guys. I will monitor the situation and see how it goes.

Regards,

Sol

[P_Jensen]

I was not sure if you lived were the fuel contains ethanol, which attracts water. You can try lightly tightening the bolts around the fuel cap to compress the gaskets and o-ring, that in addition to having clean the drain line will help to narrow down the problem. Change only one thing at a time that way you will know were the problem was when it goes away.

[wncbmw]

You have some potential answers but I would add one thing. I do not believe water can enter the closed gas cap but as stated, the drain plugged can let rain water in when you gas up. Or if you gas up in the rain without cover. Or if the gas has been contaminated with water. And once in the tank, it can linger through multiple fillups.

I have had that happen and it does indeed make the bike sputter and chug badly. My solution is a liquid 'dry gas' product (brand names vary) that absorb the water. I spent one of our annual Bash gatherings riding a sputtering machine in the rain until we stopped at a bike dealer, added a can of whatever 'dry gas' product they sold and the problem disappeared almost immediately.

Many folks, including me, add some Seaform gas conditioner periodically to the tank as a preventive method.

Good luck.

[Soliton]

BMW dealers here can sometimes run to 400% the US cost of a part and often need to get them in stock.

I had a quick look at the S100RR gasket and...

1 - Buy 1.5mm x 150mm Nitrile Rubber sheet (It's fuel resistant and can be bought in short lengths about $4-$6
2 - Remove the fuel cap
3 - Trace around it on the rubber sheet.
4 - Cut out the circle neatly
5 - Cut an inner circle out leaving a donut like shape about 20mm thick
6 - Fit the donut around the fuel cap
7 - Neaten the edges by pushing the "gasket" up or down gently
8 - Refit and tighten bolts
9 - New gasket, indistinguishable from BMW part.

Yay!