Topic: What does a wrinkle tank look like?

[Yamahawk]

I am getting ready to paint the tank on my 1971 CB750K1, and it looks like an original tank... I flipped it over, and i saw it has 'wrinkles' in the underside of the tunnel. Is this a wrinkle tank, and if so, is it worth more than a standard one?
Charlie

[Trav-i]

That does not appear to be a wrinkle tank.  If you look in the filler hole on top the top of the hump for the frame back bone will have a series of wrinkles.

[Stev-o]

Look inside the filler opening and you will know immediately if it is a wrinkle tank.

[Yamahawk]

Ok! Thanks for the replies, and clarifications on this! It does NOT appear to be a wrinkle tank, just an old SOHC 750 tank in pretty good shape. I will strip away and repaint it then. What confused me is to where the wrinkles were supposed to be, as it has some towards the back of the tank... just like the one picture of the wrinkle tank has. It doesn't have the ones inside and under the filler cap. Thanks!
Charlie

[ekpent]

 With your double outlet petcock and the fact its on the right hand side it could be a 71-74. Let us know if you see a peek at any original paint color under the overcoat.

[Yamahawk]

Yeah its that metallic Green from 1971 I am sure...
Charlie

[ekpent]

 Yeah darkish green would pretty much make it a 71 or a 73. A joke around here is that 1973 Bacchus Green was the fastest color though a lot of people just call mine " The Army bike" 
  Wonder if some people still consider green bikes bad luck ?

[Yamahawk]

I took some pictures of the original color that was under the tank badges...Green for sure lol.
Charlie

[markb]

I took some pictures of the original color that was under the tank badges...Green for sure lol.
Charlie

Looks to me more like the K0-K1 candy blue/green.

Look inside the filler opening and you will know immediately if it is a wrinkle tank.

Yamahawk, did you check for that? The tunnel area in your pic is too dark for me to tell. The wrinkle tanks went well into the K0's. How early is your K1?

[Yamahawk]

I took some pictures of the original color that was under the tank badges...Green for sure lol.
Charlie

Looks to me more like the K0-K1 candy blue/green.

Look inside the filler opening and you will know immediately if it is a wrinkle tank.

Yamahawk, did you check for that? The tunnel area in your pic is too dark for me to tell. The wrinkle tanks went well into the K0's. How early is your K1?

My K1 is 12/70 date on the front neck label. And yes, I believe it is a candy blue/green. I checked inside the filler, and it is not a wrinkle tank evidently.

You might want to leak test that before painting it. That area behind the badges is prone to pinholes from rusting. Strip it, dust it with some flour, then fill with gas, full. Check for moisture signs... just to be sure. 

thanks calj737,
   I will definitely check that after I strip it. Currently, no leaks, I rode it last fall and have had gas in it since then, but just drained it and let it sit for a week to get it ready for paint. I am going to prime it, silver base coat and candy apple red with a clear, it is Duplicolor lacquer, and am currently looking for a 2K Clear lacquer for gas resistance. I have found several different manufacturers, that do have a 2K clear lacquer. I have also read in forums of guys who have coated lacquer paint after curing with urethane type clear. They say that modern base/clear systems of paint have a base that is very similar to lacquer, and it can be done. An intermediate coat of clear after gassing of paint may be necessary though. There are ways to accomplish this hehe...
Charlie