what tank fits my 78 cb750 K?

[mitchberry]

Hey guys,  

 I have a 78 cb750 K   (i don't think it's a K8, i really don't know), and i absolutely hate the big ass bulbous gas tank with the flippy lid thing on it.  I'm trying to make a cafe racer, and the first thing that has to go is that ugly ass tank..

I'd like to get a tank off an older model but i'm not sure if it will fit.    does anyone have any ideas as to what year tanks may fit on this frame?  (aside from the factory one)  

I don't care if i have to modify the frame a little to make it mount or fit, the main thing i'm worried about is the petcock location and it's ability to miss the head..  i tried my suzuki T500 tank on it and the petcock is too far towards the front of the bike to work..  (too bad because it's a lot cooler looking of a tank.)

thanks in advance...

[Re-run]

Well if you want a drop on tank, then you will need to use a 69-76 tank for the sohc. I think the older tanks look like a big blob myself, I prefer the 77/78 tanks but most people feel the 69-76 tanks complement the cafe style better. Try to go with a 74-76 though as I think some of the earlier ones have 2 petcocks and you would need to cap one.
You may need to modify your cafe seat too to account for a shorter tank or you may have a gap between the 2.

[mitchberry]

Thanks for the response.  Honestly, the tank that's on it isn't -that- bad.. and it would be a great tank if i were going for an OEM restore, but i do agree, those older tanks lend themselves much more to cafe racers. I bought an awesome fiberglass tank a while back for my 69 suzuki T500 from a dude who makes them and sells them on ebay, but the problem is, the coating started flaking inside it which of course got into my carbs and pretty much rendered my bike useless until i rebuild the carbs again and maybe even pull the heads off to make sure they aren't gummed up with resin crap..  

 he said he'd send me a new one and would let me pay him 100$ to refinish the old one, so therefore, i would have 2 tanks...  the tank is made specifically for the CB750 but i made mods to the T500 frame to accept the tank..  

 so.. if i decided to do that i'd be set with a tank for the cb but...... i don't trust that i wont have the same issue again.  i'd almost rather get an old metal tank..

 the only problem is that i am planning to put clubmans on this bike, which of course means that i cannot twist the bars lock to lock (i think) which also means that i cant lock the forks when i park the bike..  the fiberglass tank is narrow enough to where i don't have that problem..

 then again maybe the mid 70's tanks are more narrow than the 77 / 78 flippy top type?

[Re-run]

I dont think the earlier tanks are narrower. Shorter and taller I think.
Fiberglass tanks are iffy. Part of the reason is the ethanol in gas these days. It can attack the resin if not sealed well.
http://www.roccitycafe.com/store.php
http://www.airtech-streamlining.com/hondaz/CB750SOHC1969-77.htm
http://www.benjiescaferacer.com/forsale.html
http://www.cb750cafe.com/parts.php

Just some sites with tanks and other cafe parts.
Tanks are expensive so if I was in your shoes, given my limited budgets, I would get that tank relines and probably source a tank from a boneyard or ebay.