748 /998 Tank To Frame Alignment

its a ducati sir, they all do that :tearsofjoy:

 

Hope your frame's not had a clout...

 

The bottom left looks as though the airbox rubber is sticking out, I'm only looking on my phone so could be wrong.
Here's mine.

 

I think you've got the right of it Steve. Looks like the rubber is misaligned. Andy

 

Other than the comments above you could check to see if the front tank mounting pin is sitting and bolted correctly to the tank and also that it is not bent.

The holes do allow some movement and I have come across the odd tank that has had the pin badly fitted or is bent on the bracket. If that's the case then the tank won't sit squarely on the airbox.

Also is the front grommet in good condition and not perished or split, if it has gone soft or has split then again it will cause the tank not to sit as tight or possibly not squarely.

The tank on my 998 is not a wonderful fit but it does sit square on the frame.

 

Your bike is running the later, fatter air box seal (which is a good thing).... The frame and tank were never altered from the original bikes which ran a much thinner seal (not so good). This lifts the tank up at the front where there is room to "float" but at the rear where it is fixed by the tank mount, it gets pulled down and compresses the seal at the back.
Doesn't look like there anything to worry about just the aesthetics. Check that the small top hat spacer is in place under the grommet in the rear mount. If that's missing then the rear gets pulled down too far though.

 

Personally, I wouldn't do too much. The tank is sitting how it wants to sit and bending brackets and mounts will put stresses in to the assembly. Check the front mounts are secure and the rubber is in one piece, but I wouldn't start bending anything.
If the seal at the back is heavily compressed (it looks like it might be) then add a spacer under the mount if there's enough thread on the screw, or use a new longer one with a spacer in the grommet (the OEM screw is shoulder'd)

 

I fitted the thicker seal to mine at the same time as fitting a thicker (EVR) airbox. This makes the tank difficult to fit as everything is very tight, really it's a 2-man job as you ideally want 2 hands on the tank and a third to fit the screw but after some practice I can manage on my own.

I find it best to lube up the seal with vaseline before fitting the tank and then go around the front afterwards 'poking' the seal into place with a long handled blunt tool (normally use the long 5mm allen 'T' bar that I fit the tank bolt with).

It does seal much better than the old seal though which was, frankly crap...

 

This is the seal fitted to a CF airbox in an MY02 748S, later style seal, both the 748 and 998 share the same seal (part number 7911411A). Mine is located with a series of rubber plugs which are easily located and removed when lubricated with an appropriate lubricant, the section in the photo below has three spaced along the seal approx. 50mm apart, you cant quite see them. I have seen one or two where the plugs have been torn off due to someone removing them without lubricating. Mine wont displace in the way yours has due to those rubber plugs all the way round the seal.

 

Here is another picture, this time I remembered the flash and used a different angle looking down, you can clearly see the plugs where they exit the locating holes in the airbox on this one

 

Bettes there should be a minimal dribble (have a rag under the connectors when you disconnect the fuel lines), other than that no fuel loss. Be gentle with the fuel line connectors as the O rings are subject to damage easily and will leak when it is all back together.

 

The front fittings for the pin are captive and do not leak. If they have never been out before you will find that they have been locked with thread locker.

As mentioned only the pump is likely to lose a small amount of fuel at the joint, although it's better to take the tank off when it's got little fuel in it as it can be quite heavy.

Personally I would make sure I had spare O rings before taking the tank off and disconnecting it. They are indeed very easy to nick or damage. I use a small smear of grease on them all the way around the O ring when refitting and make sure they go in squarely and you feel the plastic elbow lock into place.

 

Use "Red Rubber" grease (yes that is its name) which you should be able to scrounge off your friendly work shop in a one use small sachet. If not, Halfords do it in a tub and it's not expensive. Andy