Fuel tank blues

The frames are almost identical.

The B model has mounting points for the fairing in front of the headstock and on the down tubes either side of the engine.

The B model has different brackets fitted to the seat rails to take the split seat and luggage.

There is no difference between the A & B model top rails between the tank and the engine though

homer01 wrote: has the tank been pressurised and bloated underneath somewhere causing it to sit up on the frame

I think you might be onto something here - bottom of the tunnel looks distorted.

hillsy and homer01 may have identified the reason the tank is too high in the rear. The section of the tank bottom between the sending unit and the petcock does appear to be pushed downward.

If so, excessive pressure inside the tank seems the only thing that would cause this.

This could happen if the tank does not properly vent. The tank is vented internally through the fuel cap. At the rear of the cap, there is an outlet spigot that goes into pipe with a rubber sealing ring around the end. The pipe runs through the tank and exits at the rear. A rubber drain hose slips over the exiting pipe.

Possibilities that could prevent proper tank venting:

Aftermarket fuel filler cap with no vent system.

Malfunctioning vent system in fuel filler cap.

Plugged vent pipe.

Plugged drain hose.

Could also have been pressurised by a panel shop for dent repair.

The paint looks pretty tidy so quite possibly could have been recently painted.

Yes, a shop could have pressurized it in an attempt to remove a dent/dents. If that is a new paint job, someone went to a lot of trouble to duplicate the original stripes on the tank, as well as the original color.

Incidentally, it seems the heat barrier material has been removed from the bottom of the tank. It helps prevent engine heat from causing the gasoline to boil in the tank which can cause vapor lock.

I hope I am replying to this in the correct manner/order.

Sorry guys, but up close and in person, this tank shows no indication of any type of stress damage due to being pressurized. The rear of the tank is too narrow, and the collars at the front of the tank are one inch farther apart than the grommets they slide on, leaving 1/2 inch of space on either side. The tank is in decent shape, paint-wise, but it is far too accurate to be a redo.

I took the bike and tank to a shop, and the mechanic, after a laugh at my expense, got it put right back on him when he could not make the tank fit. He speculated that the tank could be from a KZ100MKII, but I have no way of verifying this. I did find a number on the tank, directly under the bolt hole. That number is 9J29. I haven't had time to research this number, but will do so and share my findings. Also, I removed the heat barrier in an attempt to determine why the tank wouldn't fit. Strangely enough, when you look up tanks for the KZ1300, the only tank that shows having this barrier is the B model.

I am really enjoying hearing all of the possible causes of this problem. I can't wait till I get to something really challenging, say electrical?

Big thanks,
MZ