Duck Tail Seat

[brianhoover]

I’m a newbie here but hope some of you might take the time to help.

It’s taken almost 10 years but I am almost done with my restoration of my non-sandcast KO. It was manufactured 12/69. Frame # 1015507

During a decade of securing rare parts (including brand new NOS Tach and Speedo!) I bought a used OEM non-duckbill KO seat and a nice duckbill seat cover thinking I would have the two mated when I was ready. Sent the both off to Sargent Cycle in FL to have it done only to find out that the older style seat cover did not fit the newer KO pan. They said the earlier pan was smaller and narrower and the older pan would not fit my bike.

If anybody is in the know I would love to have the answers and would be grateful:

1) Did my KO originally have the duckbill style seat?
2) Are the pans different?
3) If the earlier pan will fit my KO, are there any companies selling restored or remanufactured versions? Are any of them affordable to mere mortals?

[donzie]

Brian try these people. In my opinion it is the best option ,not cheap but what is
"DUCKTAIL SEAL"

http://www.yamiya750e.com/index.php?main....products_id=291

[1941wld]

I just bought a seat foam from this company in the U.K. I'll give a review asap. I'm working with this vendor to buy 10 to 20 at a time. I will be selling these for cost (including shipping for the members. Spread the sandcast/K0 love. Let me know if you need one, I'll put you on the list or you can buy direct at a higher price.

[brianhoover]

Thanks for the comments and info...I might be interested in buying some foam, but I'm still not sure If I have the right pan to put it on.

Can anyone answer the three questions that I asked earlier?

[Bickle]

I'll give it a shot................

1) Did my KO originally have the duckbill style seat? Yes
2) Are the pans different? I believe that the 69-71 should do for you....after that it has a plastic document holder, other than the differences in the early sandcast version(fewer holes)
3) If the earlier pan will fit my KO, are there any companies selling restored or remanufactured versions? Are any of them affordable to mere mortals? Never seen a new after maket pan offered without a seat....even Honda NOS of today have few holes but will fit dimensionally...I believe...$250 or more...even the Yamiya seat offered is not correct as it has fewer holes. It all depends on how "right" you want it.

Hope this helps.

The bottom line is to find a trashed seat on ebay if you want correct...methinks

Steve F

[elisent]

Welcome to the world of restoration. Yamiya makes a great pan ducktail. I measured tonight same dimensions but fewer holes as early originals. I'm using their repo seat in a resto. project. Wouldn't if original. IMHO if u are restoring a bike it's the best you will find. Only flaw I saw was buckles for seat strap. Non sandcast pan should be easy to find. buy yamiyas foam and cover if you are looking to do a "correct" restoration.

[oldhemisc]

The '71s and up had a spring and associated hole for same next to the latch.

[tomcourtney]

From my understanding of the ducktail seat there is a few different versions of seat used on the production bikes that i have seen used on sandcast and diecast engine CB750's, there is the real early version where the pan is different and then there were two later 69-70 seats maybe from different suppliers one a puffey vynal top cover and the other a more smooth flat top, and then the K1 seat without ducktail which as mentioned earlier the pan has the extra threaded hole for the seat latch catch spring, otherwise the pan is the same as the two 69-70 ducktail seat bases. TC

[hondasan]

Regarding differences in the SEAT PANS, to my knowledge there are a minimum of three types which will fit the sandcast/K0's..

Early sandcast types (possibly only a few hundred bikes - my#302 has one of them) which have fewer holes through which the foam can be seen, and also a single M6 threaded hole which serves NO PURPOSE whatsoever (and is in a different position to the K1's M6 tapped hole).

Second sandcast (and K0) type which has more holes and now does not have the "redundant" M6 hole.

Then of course the K1 seat pan which can be used directly on the sandcast/K0, but does have the extra M6 hole for the release spring. The fact that the seat trim and strap / buckles on a K1 is the same as sandcast /K0 means that a used K1 seat is ideal to re-foam and re-cover to "create" a sandcast / K0 seat. The M6 hole for the release spring can be welded up, and most people will never know!

With Honda, there is always a "but", if you look closely enough at the detail. On my earliest seat pan (#302), a number of the metal tangs which hold the cover on at the rear edge are actually on seperate metal pieces which Honda then spot welded onto the pan. On the K1 seats that I have, these tangs are pressed direct into the pan. I BELIEVE that on the K1's, that Honda may of increased the number of aluminium fixings which hold the rear stainless trim on from four to six. Oh, and if you decide to buy a NOS K1 seat to covert to sandcast/ K0 type, you will find that the chrome buckles have now been changed to some kind of double arrangement which looks different. You could buy the buckles and seat screws from Yamiya, but whilst the screws are slightly different, the buckles that I got were simply WRONG - too narrow.

Does any of the above matter - that's for you to decide.

Later K2 to K6 seats of course fit, but only if you also using the lock assembly, and in detail the pan is completely different and not suited to conversion to early type.

For my money, particularly if the cost of a used sandcast/K0 seat is too painful, with a little effort a solid K1 seat makes a sound basis for creating that correct looking early seat.

If any one can add to the above, I'm always interested to learn more.

Cheers guys - Chris R.

[brianhoover]

What I think I've discovered in the last couple weeks is that the ducktail pan is smaller and norrower than a later KO pan. My assumption that I could use a ducktail cover and foam on this pan prooved to be wrong.

My pan is from a KO ( I had a 1973 K3 so I know the difference....spring latch and plastic compartment) and the ducktail cover I bought would not fit.

I just ordered a reproduction seat with plastic pan but I will continue looking for and original seat in ANY condition. Any leads would be greatly appreciated.

[Steve Swan]

Brian,

Please drop me an email so I can reply to perhaps be of help.

Steve
sandcast232@yahoo.com

[tomcourtney]

Hi here are some pics to clear things up.
On the CB750 sandcast and diecast K0's there were Three different seats used.
The low vin bikes had a seat base like this also a bigger 19 litre fuel tank,



less vent holes and the threaded hole possably for a seat stop wire but not used..


Then the seats used on later sandcasts and diecast K0's there were two types used that i know of, both had the same base..
which looks like this..



They had different covers a flat type ducktail and a puffy type ducktail
The flat type...




and the puffy type...



seen together they are very different looking the closer is what i call a puffy one..





then there is a K1 seat that has the latch catch spring this pan is the same as the later sandcast and diecast K0 with the extra hole for the spring and can be used for a K0 with new foam and cover...
The K1 seat pan;;



and here is the bases lined up they are all the same width.. rhs early sandy, middle later sandy and diecast K0 with two different covers and left a K1, hope this clears it up a bit
There was mention that the trim has more rivits yes the two short stainless trims at the front of the seat have three rivits each side on the K1 pan the K0 pans have two rivits each side the rear trim has 4 rivits on all pans,
and yes the cover retaining tangs on the K1 seat pan are pressed ..
Another thing to note, the bolts used on the very early and the K0 seats have unmarked heads the K1 seat has small #8 bolts TC

[tomcourtney]

What I think I've discovered in the last couple weeks is that the ducktail pan is smaller and norrower than a later KO pan. My assumption that I could use a ducktail cover and foam on this pan prooved to be wrong.

My pan is from a KO ( I had a 1973 K3 so I know the difference....spring latch and plastic compartment) and the ducktail cover I bought would not fit.

I just ordered a reproduction seat with plastic pan but I will continue looking for and original seat in ANY condition. Any leads would be greatly appreciated.

Carefull i think some of the repo covers are too small...

[kp]

Tom. That's great info for the members and I for one appreciate the fact you posted actual pictures of the various seat types. I tend to believe this and what you have pictured because we do see on ebay some seats are more puffy than others. Could be the material used in the lining and could even be the upholsterer doing the seat, but it is very clear there are differences.
Brian, there is no smaller seat base from an early K0 to a later K0, The dimensions are all the same. Maybe you could post a picture of your pan as it may not even be a CB750 pan. if you have trouble please send me the pictures and I'll post them for you
KP

[Steve Swan]

Tom, I 2nd what KP wrote !

THAT'S REALLY GREAT INFO !