Topic: 400 Four tank on 74 cb 750 K

[754]

Been think of doing this a while..maybe for a tracker project, but for now I tried it on a 74K.
The rear of tank must be lifted to allow carbs to open, so i made about a 3/4 inch wood spacer that fit over the stock rear mount, with the lower 1/2 of the stock rubber mount. The spacer should probably 7/8 then inset the tab into the wood as shown.
 The tab at the back, I bent over , it interferes with the seat, bent down it clears
 Stock 75 petcock fits and ends up in stock location, but closer to center.
Wiring is tight at front, but move it a bit and left side full lock, right side the brake line hits, will try to relocate ahead of fork
Looks a lot narrower and tighter up front, from seated position, you see more of the motor.

[754]

Top view and other side..

[carnivorous chicken]

That looks good.

That super long rear tab on those 400F tanks always made me scratch my head -- if the bike is a keeper for me I just grind off most of it leaving enough for the rubber mount to work.

[754]

With PD carbs or webers tank can be run lower,but be going downhill a bit.

[BPellerine]

nice subtle change frank,look even better with webers!bill

[scottly]

Everything looks better with Webers, Bill!
Frank, I like the way it looks. I've always been a fan of the 400 tank's lines.

[gwallis]

754:

Is it possible to retro fit a 1976 CB550F tank in the same way for a 1973 CB750?

[754]

500 tanks require a lot of bashing to get clearance, so 550 maybe the same.
Not sure why the 400has so much room under it..anyone know how much the 400 tank holds in liters?.

[scottly]

The only numbers I can find say 3.7 gallons for the '75-76 tanks, and 3.5 for the '77 tank.

[754]

Its narrower by about 1.5 inches, you can see part of the tops of the outer carbs, and the motor is noisier...makes motor feel bigger and bike smaller.

[BPellerine]

+1!

[754]

Well I must say , feels like a bit smaller bike..a bit more visceral..you hear more motor noise ..sort of. Like more machine stuff happening.. Now the instruments look bigger and maybe should be running something smaller.
 Today i filled the tank, will check mileage. It may be sitting snug against some of the wiring, getting a bit of a drumming or feel slight vibration off top of tank. Cant be hitting coils, if you take the 3/4 inch wood piece out it swings right down. Sure changes the bike, reminds me a bit of why choppers are exciting..

[Retro Rocket]

That 400 tank doesn't look as small as I thought it would....

[strynboen]

you just need the small instruments from the erly 400 four..they are nice....i have a ekstra 400 tank..think to fit it to my 550..its must be the coils space vho gives the ekstra air under the tank..on the 400 the fuel tap is a problem..it sits cramped close to the caburettors(stock one)