XS750 tank on a XS400 which has XS650 mounting studs?

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armyofda12mnkeys

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hey all,
Just curious. I have a 1978 XS400 and I had the mounting studs moved/re-welded for a fiberglass gas tank a while back. The guy put the 'tank studs' on the gas tank for an XS650 so the 'frame studs' had to get moved as well (hopefully using the terminology correctly).

I was curious, can I just pop a XS750 tank right on if my XS400 has XS650 studs? (or do i need to do some more modification to make it fit).

Thanks!,
Ari
 
Most like the look of the XS750 tank for a café bike. The XS750 tank front mounts are just the opposite of the XS650. The XS650 has the rubber bungs on the frame. The Xs750 has the rubber bungs on the tank.
To install the XS750 tank you need to install the cups the rubber bungs go into on your frame. Getting them the right height and width will be the hard part.
Leo
I just reread this and I said that wrong, the XS650 has the cups on the frame, rubber on the tank. The XS750 has the cups on the tank, rubber on the frame.
Most just bolt the rubber onto the frame.
Leo
 
Last edited:
Hey Scorpio...
Well I have a fiberglass tank now on it... but its getting cruddy inside because of gasoline I assume. My old cool tank:
http://www.flickr.com/photos/7979944@N04/4869750397/sizes/z/in/set-72157623939536110/
On a side note: the ebay tank guy put 'mounting studs' on the front of the tank where he would usually put for XS650s customers he said ... but i just realized the XS400 (and maybe XS650) doesn't have any 'front mounts' really (only where those 2 round metal parts with rubber attached to them on the front stock tank go into. The Stock gas tank i think is more stabalized by that and the back metal part that gets screwed in near the battery). So I guess everyone who bought this fiberglass tank had to weld some metal on the front of the bike where his mounts are so it could be stable on the bike. I think I'd probably remove those welds now, and the rubber-round things have moved like XSLeo just said.

The XS750 would still be like a cafe-like tank... The XS750 tank has a tank with the dents in it (not all of them had it though, looks more rarer) so it'll look like this:
http://motohype.com/wp-content/uploads/2012/01/xs1.jpg
http://i993.photobucket.com/albums/af56/petercab_2009/DSC_0161.jpg
It looks really cool!
 
Just a followup to this question.
Getting ready this month to weld on some small bits of metal onto frame which would hold the rubber bungs of the new XS750 tank...

I'd also like to take the old 'cups' off that fit the old XS400 tank.
Can I just use a Dremel to cut this off by working at it from all the sides,
or maybe just a screwdriver pounded in between with a hammer if possibly as Im not sure how welded-on/stuck it is to the frame?
14209412948_8fba8c551f_c.jpg
 
DARKMIDKNIGHTWARRIOR said:
Could you just cut them off not trying to save them? Then use a piece of pipe that has the right diameter to make new mount cups.
Click to expand...

Well i could, I just want to cut it off as smooth as possible.
Only really have Dremel to do that (and my standard tools).
I was hoping its has weak weld/connection on the frame and I could just hit it clean off with a hammer and screwdriver hehe.

Hmmm, LuckyEight, thanks for the idea. Maybe I'll give that a shot.
 
Yeah those spot welds are pretty strong, so hitting it off is probably not going to work. Best way I've found is to grind JUST the spot welds until the metal is fairly thin, then try prying or hitting it
 
patrock said:
Yeah those spot welds are pretty strong, so hitting it off is probably not going to work. Best way I've found is to grind JUST the spot welds until the metal is fairly thin, then try prying or hitting it
Click to expand...

Hey patrock/LuckyEight...
So are the spot welds these 2 (or maybe there's a 3rd one hidden somewhere too?) that 'stick out' from that metal piece.

EpY3y09.jpg


In LuckyEight's grey-frame pic, he mentioned 3 welds (those 2 'sticking out' parts in his pic dont seem to be what he is talking about removing),

but i dont really see those 3 in my pic above (black frame), seems like the welds are 'under' the metal piece then?

aCE2QLK.jpg


Should I drill out the 2 i have highlighted, or try and look for the other 3 he mentioned (but looking at my pic, i dont seem to see them... i just assumed i'd be drilling out the 2 circles that look like they are coming from the frame into the metal piece).
 
Yes try to look for a third. but in luckyeight's picture the 3 spots are exactly what you should be grinding down. Because those are the only spots it is attached to the frame. If you can't see the third spot then work on the two you can see and start prying, you should be able to find the last one. If there really is one.
 
BTW how would you recommend drilling those welds out... Was orignally thinking super-hard titanium? drill bit.
But those parts that 'stick out' are slightly rounded. so i assume the drill is going to be hard to keep on that spot at high rpms, and all over the place.

Maybe Im just confused, since Im still assuming the parts that stick out Im drilling are the 2 red arrows in my pic,
otherwise the 3 red arrows in Lucky Eights pic dont seem to exist for me, or they are under that part and inaccessible unless I try to Dremel underneith the part with one of those Dremel flat super-thin metal-cutter attachments.
 
your spots are under the paint...my frame is bare metal (chemically stripped) so they are visible...actually you can see these spots on all over the frame...
I don't know what are the other 2 spots next to these 3...
If you will try to drill them out, hit these spots with some punch tool (don't know how to call it) and make some dents for your drills... Sorry for my bad english...
 
ok i see what you're saying now.. those two little dots in your picture are probably just markings on the cups and having to do with spot welds. Your spot welds (the same spots that you located in luckyeight's pic) are there i guarantee it. they are just hard to/or can't see them under the paint. maybe you should grind off the paint with the dremel and look for any metal discoloration, which are signs of spot welding. then go from there and i do not recommend drilling them out seeing as how the gusset inside the frame is probably without holes for a reason.
 
actually I don't mean drill...rather like milling cutter with flat or round end (man these expressions are killing me). Hope you know what I mean...:D

Try to sand the paint off....
 
You can drill through them without causing problems! Three little holes will not matter. You can seal them later before paint with body filler. Like stated use a center punch to make a dent for the drill bit to ride in and go to town.
 
You can buy a cheap spot weld cutter at most auto body supply places (less than $20). They are like a small hole saw for metal used in an electric drill. I used to do a fair amount of auto body hobby work and used them whenever I had to seperate spot welded body parts.
 

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