Bigger tank for 81 kz650

I have an 81 kz650 csr. i am wondering if anyone makes a larger tank for these bikes. i believe it currently has a 3.3 gallon tank

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will it only hit against it when bars fully turned? or always rubbing against it?

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How about a tank off of a KZ1000/1100 CSR/LTD/Spectre?
Are they larger?
Are the mounting points the same?

Might be feasible to decrease the lock-to-lock swing distance of forks, and thereby keep the forks from touching the fuel tank at full lock position on either side.

This may sometimes be accomplished by adding material to increase the diameter of the metal stub/post that serves as a stop to limit sideways movement of the fork when the stop tap meets the stub/post.

Examples would include a larger ring (short tube) pressed onto stub/post, or welded, or set screwed, or whatever other means to hold the ring onto the stub/post.

Might even be feasible to press a tightly fitting short length of heavy duty rubber hose (such as automotive fuel line) onto the metal stub/post.

Also possible to weld additional material onto the stop tabs so they make contact with the stop/post sooner.

See image below.

Good Fortune!