Topic: Second K1 Getting Closer

[TideWater2]

I have the front brake to complete and I’m waiting on my January appointment at the engine shop to clean/sync the carbs and new tires then I think she is done. I first seen this bike in October 2022, but I didn't get it bought. After doing more research I realized I should have bought it. I tracked it down and got it bought this spring, after I had bought the bike in the background. This bike came out of a collection in Arizona several years ago and now that I have paperwork and history, it was restored in 2009. It has brand new NOS HM300s. I installed a NOS body set that I already had. Still a couple details to get right, but I got it about where I want it.

[Kevin]

Dang! That's a sharp looking bike!
You are very blessed to have two !

Sent from my SM-S908U1 using Tapatalk

[BenelliSEI]

That looks great. My K1 is also on a set of NOS HM300 pipes I found +15 years ago. Best riding, best sounding cb750 I own. My favourite ride.

[Stev-o]

Looks good, let us know when it is running great.

[kyle750]

WoW . . . your CB750 is a Real Beauty!  Huge Congratulations!

[TideWater2]

Thanks, Kevin & Kyle750 for your kind comments. It really wasn't the plan to end up with 2 bikes, but as I said before, I hated I didn't buy this one the first time I seen it. I'm sure most on here have the same problem.

BenelliSEI, I think 90% of my love for these bikes is their sound. I do prefer them without the baffles though, I might wait awhile before I pull these.

Stev-o, it runs now, but the old tank had some crud in it and the former owner didn't know or didn't care when he started for me to hear. I started it to warm up enough to change the oil after I changed tanks. I will put new fuel lines on when we clean the carbs as well as new throttle cables.

My dilemma now is the seats, both original seats are very good shape, but the foam is turning to dust. I have had two different upholstery shops tell me they could do the vinyl but won't touch the foam. I never would have thought foam would stump the tech world we have today. I do have a NOS seat that I will put on this bike but would still like to get the original done on the first bike.

Thanks again

[RAFster122s]

Yamiya has reproduction foam for the seats, but sit down before you look at price. Repro seat complete as well if you want to spring for it. Gumtwo on eBay has excellent repro covers they make...few others out there too...
The embossed patterns are something upholstery shops typically cannot do as the heat embossing presses are patterns unique to Honda and the model...
Custom seats like Corbin Gunfighter are great options if you want something sporty and comfortable.
Welcome to forums.
David

[Rayzerman]

Check Gumtwo's covers... I believe they are stitched, not embossed like the originals.... if that matters to you.

[TideWater2]

RAF & Ray,

Thanks for the reply, but my covers are in great shape, just need new foam. I looked at the foam on Yamiya, but they don't have the K1 currently in stock. There is some on Ebay from bike-parts-llc and top-quality-covers, but I know nothing about them. They are not scalloped on the top side; I assume the originals are.

[BenelliSEI]

In my experience your +50 year old seat cover may look good, but when you start to work it you can easily be damaged. “Stretching” it over the new foam will really stress it too. I’ve tried different vendors and Yamiya is by far my preferred source.

For my early 1969 I ordered their “red foam” and a cover. Superb quality, perfect fit, and absolutely identical to the original. I did have to wait a while for them to be in stock on the foam. Since you have an extra seat, consider a full rebuild on the original. Pricey, but definitely worth it! Highly recommended.

[TideWater2]

In my experience your +50 year old seat cover may look good, but when you start to work it you can easily be damaged. “Stretching” it over the new foam will really stress it too. I’ve tried different vendors and Yamiya is by far my preferred source.

For my early 1969 I ordered their “red foam” and a cover. Superb quality, perfect fit, and absolutely identical to the original. I did have to wait a while for them to be in stock on the foam. Since you have an extra seat, consider a full rebuild on the original. Pricey, but definitely worth it! Highly recommended.

Full rebuild meaning foam and cover from Yamiya? How does that compare to just buying Yamiya repro?

[MauiK3]

Yamiya also has a seat option that is cleverly cut down a bit for those of us with shorter legs. Looks stock but with a slight dip. Great seat.

[Stev-o]

Benelli brings up a good point, the old vinyl may fail when replacing the foam but I would try it, you can always buy a seat cover at that point.

Z1 sells great parts, is the K1 seat foam different that the K2 or 3?

https://z1parts.net/seat-foam-honda-cb750-k3-k4-k5-k6-1973-1976/

Or eBay has a couple...

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2332490.m570.l1313&_nkw=seat+FOAM+1971+HONDA+CB750+K1&_sacat=0

[TideWater2]

Benelli brings up a good point, the old vinyl may fail when replacing the foam but I would try it, you can always buy a seat cover at that point.

Z1 sells great parts, is the K1 seat foam different that the K2 or 3?

https://z1parts.net/seat-foam-honda-cb750-k3-k4-k5-k6-1973-1976/

Or eBay has a couple...

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2332490.m570.l1313&_nkw=seat+FOAM+1971+HONDA+CB750+K1&_sacat=0

I don't know if the foam is different on the K1 vs K2. Does anyone know how close are these replacement foams to the originals? Do the square pattern have coralating foam on the original?

[BenelliSEI]

Benelli brings up a good point, the old vinyl may fail when replacing the foam but I would try it, you can always buy a seat cover at that point.

Z1 sells great parts, is the K1 seat foam different that the K2 or 3?

https://z1parts.net/seat-foam-honda-cb750-k3-k4-k5-k6-1973-1976/

Or eBay has a couple...

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2332490.m570.l1313&_nkw=seat+FOAM+1971+HONDA+CB750+K1&_sacat=0

I don't know if the foam is different on the K1 vs K2. Does anyone know how close are these replacement foams to the originals? Do the square pattern have coralating foam on the original?

The foam is just smooth. The quilted pattern is just in the cover.

[kyle750]

Not to hijack a thread but wanted to show my seat for your thoughts and opinion.  Looks good to my eye with vintage embossed details and a pillow like puffy top.  I am quessing a replacement cover but I really don't know.  Looking at the underside the foam is red and not hardened or saggy at all.   Very comfortable seat. 

Late Edit:  It might just be the lighting but it looks like the horizontal lines were applied first and then the vertical lines.  The vinyl material is very soft and feels more like leather than plastic.  The seat for the CB750 really is very nice design as the embossed stitching mimicks the old world craftsmanship of a well made horse saddle.

[TideWater2]

You're not hijacking at all, but I'll let the more experienced answer your question.

[HondaMan]

The K1 seat is different from the K0 and the K2. The K2 had/has the first 'scalloped' thigh reliefs that let the legs reach more straight down and over the side covers, relieving the 'slide forward to stand' move each time the bike stops in traffic. I had a K1 first and then the K2 I still have, and the difference was dramatic when I got on the K2. The K1 has a Hi/Lo sort of arrangement for the passenger/rider, which added some padding over the rear frame 'hump' for the passenger's backside that was an improvement over the K0.

[BenelliSEI]

Not to hijack a thread but wanted to show my seat for your thoughts and opinion.  Looks good to my eye with vintage embossed details and a pillow like puffy top.  I am quessing a replacement cover but I really don't know.  Looking at the underside the foam is red and not hardened or saggy at all.   Very comfortable seat. 

Late Edit:  It might just be the lighting but it looks like the horizontal lines were applied first and then the vertical lines.  The vinyl material is very soft and feels more like leather than plastic.  The seat for the CB750 really is very nice design as the embossed stitching mimicks the old world craftsmanship of a well made horse saddle.

If the cover is not cracked or split, just ride it. The “red foam” is not likely the original, so your seat may have been refreshed all ready.

[Don R]

 A fifty year plus red foam would surely be slowly sifting through the seat pan holes. I know one of mine is.
 I'm thinking the K0 and K1 seat pans are pretty similar. I considered adding the red foam ducktail and K0 cover to a K1 seat to simulate a K0. For now, it's just got a K1 seat on it, but with a 71 title I'll blame Honda for a K0 discrepancy.