Later Tank / seat fit '89 model info?

[jboogie13]

The seat pan isn't the biggest problem, it's the covering on the seat. It would get stretched so hard if you had a passenger, it would rip

uh...what?

[Joolstacho]

Oh forgot something else important! You need to "fabricate" 2 spacers for the back. The '01+ had a slightly more upswept tail section of the frame. The new style seat will rest about 1.5" above the rear seat support tab thing. I painted 2 wooden blocks black and then attached them to the frame. Problem solved. You don't need to do that if you only ride solo, but if you put a passenger on it without those blocks, I can say with about 95% certainty, you're going to crack the seat pan 

I think the point is that the later seat has a different 'step' angle on the base, meaning that to align with the rear catch cross bracket on the older frame the newer type seat either has to be bent down in the middle, or you need to add spacers to support the back of the seat. But then you'd have a 'fit' problem with the sidepanels probably.
That right?
BTW my older type seat fits with newer tank fine, just apart from that raised seat 'nose' that is a it too tight on the tank rear, but I'm trimming mine down so it won't be a problem.

[mustangGT90210]

That's correct. Because of the step angle, if you heat and bend the bottom of the new seat pan, it will fit on there good I would think. But there is not enough slack in the material that covers the seat to accomodate the new bend in the seat pan.

I tested this by pushing down where a passenger would sit. The seat pan would bend all the way down to the supports on the frame, and the material in the "step" between rider and passenger seats was extremely tight, to the point the fabric over the rider seat was sitting about an inch above the seat foam from being stretched. I have no doubts if I sat on that bike with a passenger, that seat cover would have ripped.

So I made supports and threw a petite passenger on the back 

Basically all I'm getting at is, a 1" spacer under the rear seat supports solves the issue, and keeps your seat from ripping, cracking, etc.

[Joolstacho]

Update on the seat/fit etc.
Here's the bike with the leather seat cover from 'Topgaiters' (45 quid via ebay.)
Not perfect, but I'm reasonably happy with it. I cut 70mm off the base front bollock-crusher to make it blend better with the tank, aligning it with the tank 'scallop' line.
The leather is nice quality with nice stitching, and fits the seat well.
Next I'd like to get an old seatbase and modify it with fibreglass to get it to blend nicer with that tank 'scallop' shape - needs little curve/extensions at the front to 'fit into' the scallops.

[Joolstacho]

Update#2.
Looks as if it's the newer type tank that causes the seat to sit up a bit at the back. Seems to me that the seat slot in the tank rear mount may be a little lower than on the older type tank, holding the seat down a bit further at the front , making it (maybe 5 - 10mm) higher at the back. It looks fine though. Works.