Fitting GPz1100B1 fuel tank on a Z1100R

Any idea's or experience had with fitting a GPz1100B1 tank to a Z1100R.

The tank that had replaced original Z1000R was a close to exact match, but on preparing ready for paint rust and deep pitting was found in the obvious place where the Badge goes (Last tank rusted out on seems) I have pressure tested, its OK but the pitting it very deep and I'm sure it will leak soon and a waste of money having it painted.

I had wrongly thought that the GPz1100B1 tank was exactly the same and brought one before I realised the differences, its now on its way from Germany. In very good condition, paintwork looks perfect and around the badge area also very good. no rust on seems either.

But since parting with the money I manage to find pictures of the underside and notice it has Different gauge sender, not a problem as sender is on tank. But the fuel tap hole is different and in the wrong place.

I had a thought that if a small oval plate was made with the slot for fuel filter and 2 nuts welded on the back then a hole cut in the bottom of the GPz1100B1 tank in the correct position then the plate sat on the top and welded water tight around, and two small patches welded over the old holes I wont need. Its a bit off faffing around and expense of getting it welded but I'm hoping I will end up with a really good sound tank to send off to be painted (rather than paint the original and it later spring a leak)

Although they both have the sae capacity 21.4 ltr and appear the same. I'm hoping that they are the same shape for the new decals and positing of the tank badge within them.

Also I wonder if GPz1100B1 tank will fit the front frame mounts and rear and also be in the right position sat on the frame for alignment and not be wrong, i.e. to short/long or rub against top of engine or carbs air filter box etc.

Its very hard to find Z1100R/Z1000R tanks in good condition and I'm hoping the more available GPz tank will be a good alternative.

Any advice really appreciated.

Can you upload pics of the pitting area of the tank? Should be reparable with some soldering skills.

Thanks for your reply Scirocco. I will take photo's later and put up for you, I had kind of written tank off due to pitting, worst is around the badge area, but unknown what is behind the strip that takes the screws, an area that you cant get to as the strip is spot welded to the tank in the recess. I thought if it's going to cost £400 to paint tank I just as well get a decent one to paint, didn't want to risk paying for paint and later tank leaks. I have this new Gpz tank that looks near mint arriving in a week or two.

The dot welded strip for the screws can be (must be) removed with a special drill. You only have two dot weldings to remove.

Hi Scirocco, Here is the picture you asked for.

As I have paid for the GPz tank I would rather look at moving the fuel tap as a solution, providing many factors are correct....
Like the tank is the same size and shape,
fits the cups fit the front mount and rear mount,
fits and it sits on the frame giving the same clearances to engine and Carbs,
aligning with side panel, Badge location in the same place. (I don't want much do I,LOL)

But fixing the Z1000R tank for spares or back up would be a good Idea.

The pitting is Deep, I don't know how it still holds fluid, when sanding around the badge recess the rust smelt of stale petrol. Its filled up with white distilled vinegar to help de-rust it and not leaking.

Why would you remove the metal strip?
Those bits are designed to go all the way thru.
Do you trust yourself not to blow thru the side of the tank.
What is it like on the inside?
Is the seam at the bottom in the same condition?
The area where the badges fasten to?
I have use epoxy to fill similar holes before.
Just DO NOT remove any more of the base metal.


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Hi Nebr_Rex, thanks for your comment.

I have ordered a nearly new condition Red GPz1100b1 tank due to rust and pitting in the badge area in the pic I attached earlier in Green Tank. so I will block old fuel outlets on the new Red tank and have Z1100R tap put in with a small panel of steel in the correct place.

Scirocco has suggested the old tank can be fixed. when cleaning the rusty area and inspecting, deep pitting was noticed, the rust that was cleared from the outside badge area stank of old fuel! Scirocco suggested about soldering this area, I said there will also be rust behind the badge bar that would also need attention too, he had said this can be removed so I can get to this rust.

The seam is 98% rust free. For now I wont be tackling any more work on this tank as I'm more interested in finding out if the new RED B1 tank will fit frame and align correctly. also hoping the badge position is in the same place as the original tank for decal positioning. the new tank is really mint condition seams and not a speck of rust on badge area, the only trouble is the tap is wrong type and place. so hope to have a plate made with nuts welded on back and have a small area cut in right place on new tank and plate welded by a Professional then this tank can go off to painter. just hoping it fits as mentioned above.

The two tanks look totally different.
Steve

Are you referring too the picture Steve!
different photo angles!
I know the outlets are wrong,
or do you know that side by side the shape of the tanks are different. HELP HELP! lol!
I took a gamble on this, I will know for sure when the GPz tank arrives and I can compare it. I really don't know the answer!

from photos they do look very very similar. any help appreciated if you have seen them side by side, might be a GPz1100 tank for sale soon. lol.

From the side they look better. From the bottom they look different. One is narrower.
Steve

From what I have seen the "J", ELR and GPz have the same top with a different bottom soldered on.
I had to switch to a B2 tank when I swapped to carbs on my B1. If you try to drill out the spot welds
on that metal strip for the badge. You will more than likely end up with some more holes in the tank.
If you have any welding done both the inside and outside need to be cleaned down to base metal
especially for TIG. Use wire brushes and Scotch Bright pads on your favorite rotary tool.


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Thanks Steve, I'm now crapping myself! compared 100's of pics side by side using photoshop to overlay on top of each other, some look like badge is in wrong position, but others look exact, varing photo angles and light reflecting off red paint makes it hard to tell, some pics also make GPz tank look narrower too.
The GPz tank is on its way now, hopefully be with me within a week, I will be all over it as you can imagine.
The last images I looked at looked exact, so I'll go to bed with that in my head.

Yeah the bottom would never look right as one photo is taken from a different view point.

I don't mind changing the fuel tap position on a realy sound tank, but its important it is exact in its size and shape.

Really appreciate your comments though.