Topic: Any other Honda (or other) tanks a direct fit on CB750 backbone?

[coma13]

I'd like to swap out the tank on my bike (K7 CB750) for something a little smaller, and definitely more narrow, and absolutely without a flap over the gas cap. I'd prefer to stay with another stock part rather than fabricate my own, but I don't know what tanks have a comparable tunnel to fit the triple backbone on the 750.

Any help is appreciated!

Thanks!

[flybox1]

http://www.roccitycafe.com/store.php


I always liked the shape of the 400F tank, too.

[MCRider]

If you're looking to do it on the cheap, a CL450 tank will fit and is a 2.5 gallon. The tanks are cheap on ebay. You'll need to rework the equalizer tubes at the back. Either widen the lower bit of the tank, or narrow the 2 side tubes of the frame.  But it fits the backbone, front mounts and even the rear mount. I think it looks real good.

[coma13]

Ding ding ding! I think we might have a winner! (or a high contender, anyway). That is more my price range and it would be quite easy to knock the tunnel wide enough to fit the side rails from the looks of that photo.

Can I survive on 2.5 gallon capacity, is the only question that remains.

[MCRider]

Ding ding ding! I think we might have a winner! (or a high contender, anyway). That is more my price range and it would be quite easy to knock the tunnel wide enough to fit the side rails from the looks of that photo.

Can I survive on 2.5 gallon capacity, is the only question that remains.

I have 2 CL450 tanks, I'm sure I didn't pay more than $25 each. I have a machine shop that specializes in tanks of all sorts for Sprint cars. I'll be leaning on them to make it fit. "Saldana Racing Tanks".

You'll have to make sure you get the equalizer tubes working between the 2 sides of the tank so you can draw it down all the way. The bike in my Avatar had a Tracy fiberglass tank, 2.5 gallons maybe. It had petcocks on both sides that had to be open as it didn't have the equalizer. So, with no reserve I was always on edge after about 80 miles as to when I'd run out. At least with the CL450 tank you'll have an OEM petcock with the reserve tube.

[coma13]

Very cool! Feel free to let me know if you want to get rid of one of those!  I dig the shape a lot and with the back end dropped down to level it'll go nicely with the look I'm going for.

[MCRider]

I have fantasies of using one for gas, then cutting the other to make the cowl portion of a cafe seat that matches. I've seen that done by forum members and it looks really neat. So I think I'll want both.  But you never know...

The rear mount tabs on the tank are very exposed as the tank portion of the tank is so much shorter than the stock CB750. But for whatever reason, the overall length is exactly the same as the CB750, so the tab will fit in the stock rubber band hold down. What that means is that there will be open air between the front of the seat and the rear of the tank. This doesn't bother me. I could make the cafe seat a little longer in the front to cover it up. But I may just leave it open.

If you are an aggressive rider, you'll know that sliding forward on the seat helps in the tight stuff, and the CL450 tank allows for this. You want your weight in the center of the bike. The long skinny tank with the seat way back and no room to move is the style people want, but as a practical matter on the street, you really don't get to tuck in for top speed staightaways nearly as much as throwin it into some tight turns. And that tuck can get real wearisome, vs something that lets you sit up straight once in a while.

[coma13]

Absolutely. I grew up riding motocross so everything I know about hard cornering involves humping the gas tank, flopping over to the side, and hitting the throttle. (I still have to fight the urge to stick my inside foot out) Hahaha. I'm building my own seat pan so that won't be a problem. I'm pretty excited about the prospect of one of these things.

[MCRider]

Absolutely. I grew up riding motocross so everything I know about hard cornering involves humping the gas tank, flopping over to the side, and hitting the throttle. (I still have to fight the urge to stick my inside foot out) Hahaha. I'm building my own seat pan so that won't be a problem. I'm pretty excited about the prospect of one of these things.

I've known about the potential of using a CL450 tank since back in the days I worked in the shops and these were current models. Now here it is nearly 40 years later and i still haven't done it...and you might beat me to it!     Good luck!

[MCRider]

There is a guy on the forum, blueturbo i think, who has done it. He cheated by cutting out the side rails to drop the rear of the tank down. many people have cut out the side railsand left them that way. its a little scary looking, but I've never know of a problem.

I would prefer to complete the install by modding the tank or the siderails and keeping the frame integrity. But that's just me.

[Trav-i]

I thought that was a picture on here sometime ago, in which someone put a chrome sided "toaster tank" on a 750 too.  Might have to try to find it now.

[MCRider]

here's Blueturbos bike in the first several posts:
http://forums.sohc4.net/index.php?topic=56783.0
It may be a 350 tank. But i love the profile, with the rear of the tank dropped to the frame level. And from the top you can see a lot more of the engine.

The toaster sided tank was the CB750 prototype pre-Sandcast. Had a drum brake too I think. Simple step up from the CB450. You may be thinking of another, but that's the one I've seen. Never made it to production.

[coma13]

Love it! I'm definitely not cutting the frame though. I'd rather pound out the tunnel and stretch to fit.

[MCRider]

Love it! I'm definitely not cutting the frame though. I'd rather pound out the tunnel and stretch to fit.

And i don't know about coil clearance.

[coma13]

Love it! I'm definitely not cutting the frame though. I'd rather pound out the tunnel and stretch to fit.

And i don't know about coil clearance.

Good point. That also reminds me I need to get my hands on some coil brackets because the ghetto-rig I'm currently running is not exactly confidence inspiring.

[MCRider]

Love it! I'm definitely not cutting the frame though. I'd rather pound out the tunnel and stretch to fit.

And i don't know about coil clearance.

Good point. That also reminds me I need to get my hands on some coil brackets because the ghetto-rig I'm currently running is not exactly confidence inspiring.

I'm about ready to put my coils on my project "Phaedrus", so i can drop the 450 tank on and report back.

[coma13]

Thanks so much!

[MCRider]

The tank fits with my Andrews Coils. The Andrews coils fit in the stock coil mounts, but the lead outlets are on the bottom rather than the ends. still I think the coils will not be a problem.
Pics: Coils mounted:

CL450 tank mounted:

We still have the issue of dropping the rear of the tank down to the mount, either by removing or relocating the frame rails, or modifying the tunnel of the tank.

[gane]

Sorry, I'm retarded.. & can't figure out how to post pics...But,,, By making a couple of spacers ( just large  dowels)  for the front  mounts, & re -mounting a rear "tang" at the rear,  the KZ 650, B1-B4 tanks  fit. Also cb 450 tanks w/ the "equalizer tubes" tweeked drop on & make up,  Either do a "great deal" to "alter" the profile of  the 69-76 CB750 k,   A "look" which until recently had become "passant", Flame me if you like, But I never cared for the "outboard motor" gas tank  "look" of eary "K's". thus my fiddling... luck G

[coma13]

It has begun! I scored a CL350 gas tank for a 6 pack of cheap mexican beer and the gears in my head have begun to turn. I'm going to consult some more knowledgeable folks on the probability of pounding out the tunnel, or I may cut it out and weld a panel back in. We shall see!

[754]

Thosepocs look like CL tanks..
 The CB 450 tank looks more like a downsized CB 750 tank..
 If you want to see a pic search Mad Mels CB 750 on the web..  some of the pics may poke your eyes out...

[754]

I should mention, some 450 tanks like 70 have paint and striping like 750s, ie red w gold stripe and green w gold..
 be cool to get an original paint one and get it to fit..

[MCRider]

It has begun! I scored a CL350 gas tank for a 6 pack of cheap mexican beer and the gears in my head have begun to turn. I'm going to consult some more knowledgeable folks on the probability of pounding out the tunnel, or I may cut it out and weld a panel back in. We shall see!

To be clear, my examples were CL450, not 350 tanks.

But the 350 may works as well. Good luck!

[coma13]

It has begun! I scored a CL350 gas tank for a 6 pack of cheap mexican beer and the gears in my head have begun to turn. I'm going to consult some more knowledgeable folks on the probability of pounding out the tunnel, or I may cut it out and weld a panel back in. We shall see!

To be clear, my examples were CL450, not 350 tanks.

But the 350 may works as well. Good luck!

Duly noted! The 350 tank fits very similarly and the profile looks pretty much the same to me, capacity appears to be the same, it may be identical for all I know. What I do know, is that the price was right!

[MCRider]

It has begun! I scored a CL350 gas tank for a 6 pack of cheap mexican beer and the gears in my head have begun to turn. I'm going to consult some more knowledgeable folks on the probability of pounding out the tunnel, or I may cut it out and weld a panel back in. We shall see!

To be clear, my examples were CL450, not 350 tanks.

But the 350 may works as well. Good luck!

Duly noted! The 350 tank fits very similarly and the profile looks pretty much the same to me, capacity appears to be the same, it may be identical for all I know. What I do know, is that the price was right!

My guess would be the 350 tank is close. Since you have to rework either, keep in touch.