Ah! Got it now. I'm thinking red foam complete seat. Didn't occur to me you're referring to just the foam. 

Put your name down at Yamiya They are selling to those who place an order (no deposit required). Seems they have lots of orders so fail to get on the website for sale. I'm waiting on an exhaust Over 12 months now
I do have a Yamiya white sponge seat for sale if anyone needs one for a K0. Brand new

Yamiya sells these new and around $20. If you're using an O ring chain use the blank off one to stop oil flow as it is only good for a non-ring chain. I tend to lube my chains with a good chain lube produce which saves on cleaning the excess oil produced from these oilers

I never stop learning. Had a need to find some plain head under seat hinge and locking tang bolts to fit to a new Yamiya repop seat. As some will know, Yamiya supplies the Tang and new bolts with their seats, however originals did not have any #8 on the head which Yamiya ones have. Anyway, I have 2 original red foam seats which have the original hinge hardware. On removal of one set of bolts I noticed thin black washers fitted to these bolts. I decided to check the second seat and sure enough these same thin black washers were fitted. They are made from a plastic material and I can only assume they were fitted to save the black paint from being scratched by the split washer. Here's a photo

You have a 1st series 17litre triple (some say double) wrinkle tank. Has wrinkles in the tunnel and on both walls of the tunnel. Not a common tank and looks to be in good condition. Nice

Yes it is certainly a sandcast although the number has been incorrectly listed as 7844. It is in fact 7344.
One can say it is the rarest sandcast group made in that the 7XXX frame numbers didn't go far beyond 7399 or 7400 if at all so very hard to fine any 7XXX sandcasts
That is by the looks of it a very very nice machine. I would like to own that

69cb750 - My bad with the name Marty. I don't need to explain anything and I don't intend putting the site in a libel situation with something I say. Let's just say the seller is not one I use and as I already said, those shocks are K1.
I know the statement about the Vietnam fenders is true. Your point is?
Joe already stated what his intention is with the following
Before I do a complete restoration in a year or so I wanted to do a minor upgrade .The bike I picked up had rust on a lot of chrome and hardware and would like to find guys who have decent take offs to use.
Fenders,  rear shocks, levers,
Triple clamp center stem cap nut, headlight screws. Headlight rim.
All chrome triple clamp bolts and nuts .turn signal bolts front turn signal stems, fork cap bolts, clutch cover and any hardware (zinc) that is in good condition but not good for a restored bike.
I'm not sure Joe could make it any clearer
Maybe my letting him know other models have these common items will broaden his search.