Forks hitting fuel tank 2008 R1200RT

2008 R1200RT, What would cause my front forks to strike the fuel tank when turned to the left? The tank seems properly bolted down.

Broken steering stop?? Has it had a minor accident or tip over?

No, nothing like that. As soon as it goes left of center the forks hit the front of the tank. I did have the tank off this winter but all seemed fine for 300 miles. I'm not sure why it started...all seems tight. It does't get to the stop, forks seem fine and the tank can't really move. ?????

The forks shouldn't hit the tank. They didn't used to, and now they do. Thus, either the forks have moved or the tank has moved, or both.

I agree that you don't see it ("Seems tight," "seems fine," and "can't really move") but one or both of them is not in its correct position.

Problem solved, mostly. After removing all the plastique and gas tank to no avail. I noticed the tank looked rather concave. I opened the gas filler to a big rush of air. There must be a breather plugged which caused a vacuum and sucked the front of the tank towards the fork.
Interesting, now I just have to find where it's plugged.
Thanks, I hate dealing with this stuff alone.

tank vent?

logdriver, 2 vent hoses that i know of.

1 in front of the gas cap. 2nd on the fuel pump cap. Just checked mine at the 48k service and fuel pump vent was rusty steel. Blew it out and greased it up.

See post... http://forums.bmwmoa.org/showthread.php?t=46879

** OR ** the charcoal canister is pluged up.???

Thanks, I blew through both hoses and the blew freely, one bubbling. I'll keep an eye on them. Right now though, I don't want to remove the fairing again.
It is something to keep in mind if you notice them touching or rubbing while turning left.

logdriver said:

2008 R1200RT, What would cause my front forks to strike the fuel tank when turned to the left? The tank seems properly bolted down.

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Can't speak to your 08, but on my 07, there's at least 1/8th inch between the tank and forks.

The 'big rush of air' is a clue that the tank vent isn't "venting".

Yes, the tank wasn't venting which caused enough vacuum to pull the leading edge of the tank a good two inches inwards towards the forks. AS soon as the vacuum was released it popped right back. I'm okay now tomorrow I'll find out where the blockage is.

logdriver said:

Yes, the tank wasn't venting which caused enough vacuum to pull the leading edge of the tank a good two inches inwards towards the forks. AS soon as the vacuum was released it popped right back. I'm okay now tomorrow I'll find out where the blockage is.

Click to expand...

Of the two hoses from the tank, one is the rain drain from around the filler neck -- not involved in tank venting.

The other hose is the tank vent. If it is blocked, air cannot enter the tank to replace the fuel as the fuel is drawn out of the tank by the fuel pump. The vent path is from the tank to the charcoal canister (right front side of the bike, under the right fairing panel). The canister has two other hoses (three total): one connected to the intake manifold via a solenoid valve, and one vent to atmosphere.

If there is a blockage anywhere between the end of the canister vent hose to the fuel tank, vacuum builds in the tank. It's not uncommon for the canister to get filled with fuel or water (overfilling the fuel tank to put fuel in the canister, or rainwater getting sucked up the canister atmospheric vent hose). If that happens, the charcoal can begin to break down and send charcoal fines to block the hose to the tank. Not saying this has happened in your case, but it is a possibility to keep in mind as you chase this issue.

HTH!

I doubt those plastic tanks are intended to act like balloons re inflation/deflation. Rather than risk any damage I'd fix this ASAP if it repeats!

Mark- nice summary.

Logdriver - please READ: http://forums.bmwmoa.org/showthread.php?t=46055 - I'm adding that info to your thread title for the reasons stated.

logdriver said:

2008 R1200RT, What would cause my front forks to strike the fuel tank when turned to the left? The tank seems properly bolted down.

Click to expand...

you crimped or crushed the vent hose when you reinstalled the tank. A lot of forum traffic (BMW sport touring site) on this topic a couple of years, well maybe 4 years ago.
I've an '06RT and I remember people complaining up to about 08.

Another pitfall

Others have caught throttle cables in a similar manner when re-installing the tank. It's easy to do.
Good luck!