Gas Tank Question - Devil is in the details

[Chakka]

I was looking for a late style toaster tank or MX to fit my 77' GS high breather. Won the perfect tank on Ebay, what do you know..it doesn't fit. The backbone of the 77 GS is so wide it must take a special tank. The narrow backbone of my earlier frames presents no problem and it wasn't even in my mind that it wouldnt fit. Funny thing is I have an early MX that came on my Six Day and it fits fine.

How do I identify the correct tank? I guess without seeing the underside its a risk to bid on it.

Chakkla

[Rain Man]

Hi Chakka,if your interested I have a new 3.5 gal plastic tank for a GS. I could check the fit on my 77 GS 400 just to make sure.

Raymond
 Down East Pentons

[Kip Kern]

The 77 is a Turtle Back and does take a special tank.

[Steve Minor]

Let me throw another wrench into the works:

My 77 400 GS frame and my 77 125 GS frame have different width backbones too, so their tanks can't be swapped either....

[Kip Kern]

Kinda like the 75 frames, 1 was a frame breather, the other wasn't, too cool.

[Mick Milakovic]

Hey Kip, I've been a member of this group for 3 years now, and that's the first time I've heard the term "turtle back".  How did that name come about?

[crash carden]

Hello Chakka, I have an original 77 GS fiberglass tank that is what you need for your bike,as it fits the high breather turtle back frame. It is in good shape,however someone has painted it white,but the underside shows the old orange color. It does not have a gas cap or petcocks but the threads are in good shape as well as the gas cap opening. If you are interested in a trade for the early mx tank that you mentioned maybe we could work out a deal. If you are interested just let me know. You can email me at [email protected]    
      Maybe we can help each other out thanks, Crash Carden.

[jj]

The '77 GS-6 enduros came from the factory with 2 styles of tanks. A larger toaster type and a 1.8 gal variation of the MX type. You typically find the toaster type on the 250 and 400, and the MX type on the 125 and 175, but I can swap either style between my '77 175 GS-6 and '77 250 GS-6. Both tanks measure 21" in overall length, both have a full 1" lip in the back and both have smooth tunnel that measures 6.5" in the back.

This link may help:

http://www.vintagejerry.com/Penton10thAniversary.htm

I like to use the GS-6 model name for the '77 instead of GS. I believe it helps to distinguish between the '77 turtle back MC-5 style frame and '76 high breather CMF style frame. Now where does the '77 100 fit into this mess?

John J Slivka

[Chakka]

Hi JJ,
Thanks for the link...TOO COOL! I love old sales info like that. Your right on the tank setups for GS-6, I have located the large toaster style tank but would also love to get my hands on th 1.8 MX tank. Those seem to be pretty hard to find. If you look in the photos section, Jack Penton's old GS-6 250 has the MX tank and it looks pretty nice.

Do you know what the difference is between the old MX tank (73-75) and the later version used in 77? At least in terms of overall shape they seem to be the same.
 
Chris

[firstturn]

Chris,
  Look at the front view of the tank and the underside is the main difference.  They are cool MX tanks and I sometimes run tehm on older bikes for more clearance for cables etc.

Ron Carbaugh