Topic: Do earlier model gas tanks fit my K7?

[rlanggard]

I want to ditch the gas tank on my 1977 CB750K7 and find a new one. I prefer the shape and look of the tank on pre-77 models but wonder if they will fit? In particular, it seems the fuel petcock on '75 and '76 models are on the same side of the tank as on my bike - therefore I would prefer a tank from one of those model years (K5 or K6). Does anyone out there know if those tanks will fit my K7?

[mystic_1]

I seem to recall that there's a length difference.  The K7/K8 tanks are longer maybe?  Don't remember exactly, sorry not very helpful.

mystic_1

[Toxic]

20 3/4" and my 77 is 22" long

As measured along the top of the tank without a gas cap being in the way.

[mazingerzeca]

It fits. I have a K6 tank on my K7. Although externally the K7 is bigger, the attachments on front and back of the tank are at the same distance and they attach to the frame on the same place.

[rlanggard]

Did your stock seat fit after you installed the K6 tank to your K7?

[mazingerzeca]

It does, but I changed it for a K6 seat too, it looked ugly. But for using a pre-K7 seat you will have to inverse the seat attachments and seat lock on the seat, because they are on the opposite side.

[rlanggard]

I didn't realize the K7 seat is different from K6 or earlier. How so? Different shape, width? Something else for me to investigate...

[greasy j]

It fits. I have a K6 tank on my K7. Although externally the K7 is bigger, the attachments on front and back of the tank are at the same distance and they attach to the frame on the same place.

I don't understand this. if it's bigger how can the mounts be the same. is it the same length only wider? or is the rear mount set in a little. and if so how can the older seat still fit? assuming it's a bit longer to go with the slightly smaller tank.

[mazingerzeca]

I didn't measure them. The K7 tank is wider, but it seems that they are almost the same lenght. The difference seems to be at the front, where the K7 tank gets closer to the steering stem. The attachments are the same, and a K7 tank fits also with a K6 seat, I have a pre-K7 seat on a K7 bike, and on another K7 I have a pre-K7 tank and a pre-K7 seat.

[greasy j]

I see. yeah they seem to go forward a bit more, but end at the same point.

[SKTP]

here is my K8 with an older tank on it...there ends up being an inch-and-a-half gap between the tank and seat. I opted not to use the older tank. But as for the mounts, they are exactly the same.

[rlanggard]

Well, what I am hearing is that I can use a K6 tank on my K7, but I had better start looking for a K6 seat to go with it. Having a gap between the K6 tank and my K7 seat would not work. I would have thought the rear tank mount would be the same for both tanks - meaning a seat change would not be necessary, but it seems this is not the case.

[Don R]

Mount is the same, tanks are different.