1973 TX650 seat foam discrepancies xs1, xs2 also

Hi, so I ordered a seat foam off ebay advertised to fit xs1, xs2, and 73 TX650. The 74 TX650 had totally different frame, etc... And yes, I have a 1973 TX650 with the flat rear peg assy, not the tubular style rear peg triangle assy as used on the 74 bikes.

I received the foam and it is incorrect. I have looked at photos on the net and all show xs1, xs2, 73 TX650 having seat with the WIDE front and UPSWEPT seat trim towards the back. The foam I was sent looks like it is actually for the SMALL front 1974 and later bikes with the flat trim that has no upsweep towards the back. Vendor claimed that it was correct. I am not going to argue with vendor. Vendor claims others have ordered this foam and had no problems, but did say others had returned it. I kindly suggested they do some research and see the wide front style early seats, so they could avoid further returns.

So, I REALLY need a seat foam for my bike. I cannot find the correct one anywhere. My bike is 100% original and I did the research to make sure I knew what I was talking about. I will attempt to post pics of my seat before and after disassembly. Can someone clarify if there is a part number or specific designation for this type seat? Were there two types of seats that came on these bikes? If the foam is unobtanium, I would consider making my own (messy), or using a different seat....but the hinges look to be very specific to the xs1, xs2, 73 tx650s. Havent seen any other seats with same hinge location/style.

Get a hold of @Mailman . I believe he had someone in this forum make a replacement seat foam for one of his bikes.

If a seller advertises a seat foam for XS1...1B...XS2..73TX then they dont know what they are doing. The 73TX650 Has a different profile to the earlier seats.
73TX seat and Pan


To my knowledge the seat pan is the same......There may be a slight difference in the XS1, and maybe 2M will verify or confirm if there is a difference.

71 ...............................................72................................................73

73 seat is one year only, it's like the 70-72 BUT the front is wider to match the wider 7 tank rear profile (the rears a bit wider also. AFAIK there are NO aftermarket foam or covers that actually fit the 73. the earlier pan does match the 73 mounting points.
73 above 72 below.

Credit for much of the following info goes to TwoManyXS1Bs.

XS1 and XS1B are the same. The battery depression (blue arrow) is narrower on XS1 and XS1B. Electric start came out in 1972 and required a bigger battery and a bigger battery depression in the seat pan -- compare to the pics in velocejoe and Skull's posts.
XS1, XS1B, and XS2 have a "wasp waist" with a narrow back half. Observe how the rear hinge (white circle) extends outside the seat pan. Compare to the TX650 pics in velocejoe and Skull's posts -- the TX650 seat pan is square in back. This is why your foam doesn't fit, it is intended for the wasp waist pans.
TX650 does not have a rear grab rail. Earlier pans have mounts in the back for the rail -- green circle.
The TX650 strap attaches differently. Earlier pans use a single bolt on each side (red circle). TX650 has double bolt holes on each side.

Dang, gggGary beat me to it again.

This picture from the combine 70-73 parts manual is wrong and represents carelessness on the part of the Yamaha documentation department. The 70 and 71 seat assemblies are the same, but 72 is a one-year only seat because of the bigger battery depression, and 73 is different because of the things I previously mentioned.

This is from the TX650-specific parts manual, correctly showing the squared off seat back.


Here's a better parts diagram of the earlier seat. It shows the seat strap which is hard to see in the first parts diagram. It shows the strap going THROUGH a hole in the cover, which I don't think ever happened. The straps went under the trim strip, but over the cover.

I am now in need of the gas cap gaskets for my 1973 TX650. The parts manuals as stated above not only do not show the correct seat...but also do not show the correct gas cap. The TX-650 specific parts manual above DOES show the correct cap. Any way you can send me the TX650 specific parts manual with part numbers....or just the page above....except also showing the part numbers. Man, these 73 TX650's were seriously one year only bikes. Not sure if the 1972 had the same gas cap.

Oh, and good news. I ended up buying a piece of foam and making my own foam for the 1973 seat. I had nothing, zero, ziltch to go by....but it ended up pretty close!!!

Mailman's seat rebuild has a vendor who made a custom foam for his seat...
Installing a new seat cover

https://www.partzilla.com/catalog/yamaha/motorcycle/1974/tx650a/fuel-tank-tx650a-xs650b
Above link shows your cap parts and numbers.
There are three gaskets, but you only really need the big one, which can be found on eBay:
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=341-24612-01&_sacat=0
Those are aftermarket, never tried one, and don't know how they hold up to ethanol.

This is my preferred solution. It is an o-ring. I have been using this one on my personal XS650 for years. The first one I bought from an auto parts store, and it swelled up in a couple of days and would fall off, and was therefore unsatisfactory. Then I ordered some made of Viton which is ethanol-resistant. Been using these ever since.

DogBunny said:

o-ring. I have been using this one on my personal XS650 for years. The first one I bought from an auto parts store, and it swelled up in a couple of days and would fall off, and was therefore unsatisfactory. Then I ordered some made of Viton which is ethanol-resistant. Been using these ever since.

Click to expand...

size? thnx!

Yes, where did you order the viton? What store?

I got my Viton o-rings from MacMaster-Carr, in an English size. Tried to find the original order, but couldn't. The one in my tank is the only one I have left. I measured it, and it must be this:
https://www.mcmaster.com/9464K47

Awesome, thanks!