XS750 tank on a XS650?

SDLars

XS650 Member
Messages
18
Reaction score
2
Points
3
Location
Custer, SD
Seems I read somewhere where someone had fitted a 750 tank on a 650 for extra fuel capacity. Anyone know what kind of fabricating had to be done to accomplish this? Other options for more capacity?
Thanks in advance.
 
Basically, it will involve swapping the forward mount “pucks” from the XS650 tank to the XS650 frame because the sheet metal cups that receive those pucks are on the XS750 tank (i.e. the gender of the forward mount setup is reversed on the 750 tank) and it’s way easier to simply move the pucks than weld new mounts on the thin sheet metal tank. You will also need to do a little minor surgery on the rear tank mount

NOTE - the pucks will mount in a slightly higher and perhaps more forward position than the present ones on the XS650 frame from what I can tell.

If you use the Forum search engine, I’m sure you’ll find details. A member named Larksnostril did a beautiful job on his as did Brassneck.

Pete
 
Here is a sloution without removing the cups from the XS650 frame
http://www.xs650.com/threads/750-tank-swap-front-mounts-another-way.15115/

a thread on the swap did remove the 650 cups. Some details on painting
http://www.xs650.com/threads/xs750-standard-tank-for-xs650.15631/

Another thread with some extra detail info....worth reading
http://www.xs650.com/threads/fastening-of-a-xs750-tank-on-xs650-frame.40170/

Interesting 73TX cafe build with an XS750 Chrome powder-coat tank.......
http://www.650rider.com/index.php?name=Forums&file=viewtopic&t=4514&postdays=0&postorder=asc&start=0
 
Seems I read somewhere where someone had fitted a 750 tank on a 650 for extra fuel capacity. Anyone know what kind of fabricating had to be done to accomplish this? Other options for more capacity?
Thanks in advance.

Hi SDLars,
like they said, an XS750 tank will fit but you have to work at it.
Your profile photo shows a Special.
An XS650 Standard tank is one gallon bigger and drops right on.
IMG_0024.JPG IMG_0019.JPG
Like this one on my Heritage Special.
 
I've done it fairly recently. Let me know if you have any questions.
Be advised your stock seat may not fit anymore since the 750 tank is a bit longer than the Special tank.
 

Attachments

  • tank mounts.JPG
    tank mounts.JPG
    66.3 KB · Views: 270
  • XS650 Cafe.JPG
    XS650 Cafe.JPG
    138 KB · Views: 224
ThatXS650Guy: sure looks sharp!

It looks like you're using the stock petcocks - correct?

It must be tight - any tips?

Pete
 
They actually clear the carb tops OK if you shim up the back of the tank about 10mm. I did resort to using a 90 degree brass fittings just after the petcock to ease out the fuel line kinks. Otherwise, no issues... You can even use the same lock from your stock tank so your keys match. It's a big improvement over the tiny Special tank. I can go 160 miles before I hit reserve.
From this view you can see the barbed fittings and the high tech spacer. The dampner is the stock 750 item
IMG_0133.JPG
 
Cool - thanks Jim!

I figured I'd need those 90 deg. spigots so I bought some already.

Pete
 
aldo5468 has some pics of puck placement somewhere on this forum.

I used the xs650 rear tank rubber on my conversion and I then carefully marked where the pucks would mount. The new mounted pucks clear the top of the stock gusset mounted cups by about 4mm, and the swing of the forks stop short of hitting the new tank by about 5 or 6mm on a full turn.

There's a small section in the 750's tunnel that can use a bit of peening for clearance, Clarence........and as noted the stock seat pan needs to have about two inches removed from its forward end to clear the side hinged seat. I'm thinking a lift off seat may be getting real close to where the front securing fork mounts to the seat pan if trimming two inches off.
 
aldo5468 has some pics of puck placement somewhere on this forum.

I used the xs650 rear tank rubber on my conversion and I then carefully marked where the pucks would mount. The new mounted pucks clear the top of the stock gusset mounted cups by about 4mm, and the swing of the forks stop short of hitting the new tank by about 5 or 6mm on a full turn.

There's a small section in the 750's tunnel that can use a bit of peening for clearance, Clarence........and as noted the stock seat pan needs to have about two inches removed from its forward end to clear the side hinged seat. I'm thinking a lift off seat may be getting real close to where the front securing fork mounts to the seat pan if trimming two inches off.
You can take 1 3/4" - 2" off the nose of a lift-off seat and not lose the front securing forks. I can't remember now exactly how much I had taken off, but it was in that range. In retrospect, dunno if I'd do that conversion again - the 750 tank is enough larger to make the bike look a bit top heavy. Probably go for a Standard tank if I had it to do over.
 
Hi SDLars,
like they said, an XS750 tank will fit but you have to work at it.
Your profile photo shows a Special.
An XS650 Standard tank is one gallon bigger and drops right on.
View attachment 125749 View attachment 125750
Like this one on my Heritage Special.
Is there a way to tell from photos of it is the standard or the special? I see lots of specials available.
 
Standard Tanks 74-79 have the cgas cap in the center of the tank. All Special Tanks have the cap to the side.
Left; 74/75..Center 76-79. Right Special 78-83
........P1000917.JPG

74/75 Standard tanks have a raised cap and no side badges., No aftermarket cap alternative. If a tank for sale doesn't have the cap it is worth considering passing up on the deal. Used or OEM gas caps are very hard to find or very expensive if you do.
P1000921.JPG74TXA-75B.jpg

76/77 Standard tanks have a similar gas cap to the specials. and no side badges. Aftermarket Caps available
These standard caps look the same as Special caps but they arn't and do not interchange
76C.jpg 76C   ..jpg77D  Blue.jpg

78/79 Standard tanks have the same gas cap as the 76/77. These 2 years have badges on the side
79F..jpg 79F,,.jpg 78E.jpg

There is a difference with the petcocks.
74-77 have manual petcocks
78/79 have Vacuum operated petcocks

78/79 petcocks are wider at the base and taller than the early 74-77 petcocks. Note in the pics, (silver tank and dark tank with badge missing), the base of the tank where they sit, you can see the earlier Tanks protrude where the petcocks sit. Later Vacuum petcocks tanks are slightly recessed to accommodate the extra height in the petcocks.

Early and late tank petcocks do not interchange. If someone has filled in the bade on the later 78/79 tank check the petcock mounting to determine what tank it is.
 
Last edited:
Standard Tanks 74-79 have the cgas cap in the center of the tank. All Special Tanks have the cap to the side.
Left; 74/75..Center 76-79. Right Special 78-83
........View attachment 125782

74/75 Standard tanks have a raised cap and no side badges., No aftermarket cap alternative. If a tank for sale doesn't have the cap it is worth considering passing up on the deal. Used or OEM gas caps are very hard to find or very expensive if you do.
View attachment 125783View attachment 125792

76/77 Standard tanks have a similar gas cap to the specials. and no side badges. Aftermarket Caps available
These standard caps look the same as Special caps but they arn't and do not interchange
View attachment 125790 View attachment 125786View attachment 125791

78/79 Standard tanks have the same gas cap as the 76/77. These 2 years have badges on the side
View attachment 125789 View attachment 125787 View attachment 125788
That's just the kind of information I need. Thanks very much!
 
How much gas do those XS 750/850 tank hold? I do love the style. I have a Standard tank on my Special. I like the extra gallon for the range it gives me..
 
Back
Top