73 fuel tank

[Luvolbikes]

I recently completed restoration of my matching numbers 73. It had a later Z1 tank with the 140mm badge screw spacing and I found an original 73 122mm tank on Ebay that needed some body work. I sent it off to Chuck Parker in Oceanside California who is widely considered the most experienced on Z1 paint in the USA.. He did a great job and it matches the side covers and tail well. When I put it on the bike there are very noticeable differences in how it sits. The front of the tank fits more forward right up to the steering head when the rubbers stop the forward travel and is more narrow. The main problem is that the tank sits up higher especially noticable where the tank meets the seat. It sits easily an inch higher than the other tank does and the rubber band has to pull very tight to reach over the tab. It appears the tank is sitting flush on the frame but just higher up. This tank appears normal and unmodified underneath with the same hidden seam and contours. Anyone familiar with the differences in the 73 vs later tanks? Is this normal or has this tank changed with the damage and bodywork? It doesn`t look right the way it sits high by the seat. I would appreciate some input from anyone who has experience in these tanks. Thanks much. John in Arizona.

[Philippe]

Hi John
put some pictures on, one picture says more than a thousand words...
Don't forget to take a picture from the underside of the tank and from the place where you put the rubbers that wrap around the frame tubes.
There must be a logical explanation.
GrtZ
Philippe

[warren3200gt]

There is purported to be 100% original 73. Does it look anything like this?

[Luvolbikes]

I will try to get some pictures up soon. I think today I'll do some measurements underneath. Even with all the rubbers removed it still sits very high. Hard to tell from the picture above what the distances are. I suppose the most useful measure would be the distance from the 4th carb top to the tank base. Thanks for responses.

[ADRIAN H]

Suspect it maybe where the rubber frame protectors are placed.

[Luvolbikes]

Well I did a side by side with the 2 tanks. The are considerable differences in the depths of the contours of the underside and I suspect at least some of it is due to the damage and repair, but hard to imagine it could account for all the difference. I was able to " gently persuade " the responsible surface to retreat somewhat and the outcome seems acceptable but not perfect. Here's a picture of Grandpa and Grandson side by side.
Does anyone know if there are differences between the 73 and later Z1 tanks (74,75) other than the badge size?

[wilsonsjw11]

Frank's 100% original 73 (72)Z1 has pattern parts on it.
Regards
Steve

[Garry.L]

Could be wrong but I thought all Z1 tanks were pretty much the same?. The change came with the 900A4 Tank.

[Luvolbikes]

Different badge mount size and I've heard a more narrow neck?

[8 Valve Mark]

wot garry says,..the tank badges at 122?mm spacing was the same from z1-z1b. then 142?mm afterwards. although; the underside profile will easily differentiate the z1 series from the later z/kz 900. on the forward facing flange (yes FFF!) of the metal plate that the rubber band hooks onto; should be be a date stamp which may or may not be clear under the paint.although whether from 72 or 75 shouldn't make much difference... merry Christmas anyway peeps! m