An upgraded & modernised GPz900r but keeping it all within reason and maintaining the original design lines of the bike.
Of grat interest was the upgrades – installation of a 973cc kit – googling shows you can still get Wiseco 972cc kits – but japan.webike now suggests that big is a bad idea as there are no longer any stock Kawasaki cylinders?. Hmm. Not something I would do just because, but when my engine does need a rebuild maybe split the difference and go forged pistons.
The ZX-10 rear wheel takes the rim width from 3.5 to 6 and probably a 190/55/17 tyre – which is a massive increase in width and only ~30mm reduction in diameter, so the side profile of the tyre and the bike still looks similar, especially with the modified swing-arm from ZX636 design still looking close to original. The bigger tyre also will have a bit more give in it, hopefully softening up the ride a tad without compromising handling. Seriously good and sympathetic upgrades IMHO.
I contacted Per.N at Wrenchmonkees who helpfully provided a bit more info on the mods.
Great idea. Hope you’ll have many GpZ 900 owners onboard : )
A “plug-in” solution is not an option. Sorry.
Too much work, and can’t remember all the details, but :
The ZX636 swingarm was chosen simply because it looks good.
Midsection of the “front part” was cut out and width was trimmed, to make it fit in the frame.
New seals and two sets of pin bearings on each side, was installed, to match theGpz 900 inner bearing “tube” and Gps 900 axle.
Shock mount on the ZX636 swingarm is off-center / asymmetric, as the shock on the 636 is mounted some centimeters towards the left / chain side.
But the mount is very wide and can be machined down so it will fit the stock link from the Gpz 900.
I think we used some parts from the ZX636 link and some parts from the Gps 900 link, something about bolt sizes and bearings…but can’t remember exactly, sorry..
So…swingarm in place, and an adjustable YSS monoshock replaced the stock Gpz item. Can’t remember the length, sorry..
ZX10 wheel including the ZX10 sprocket carrier and bushing fits without a problem in the ZX636 swingarm, I seem to recall that the chain line / left side was just right.
And maybe we replaced the wheel bearings to fit the ZX636 wheel axle, but again, not sure..
Rear brake caliper and bracket is also ZX636, and the TRW disc is the smallest available diameter for the ZX10 wheel, which happened to be the same as the ZX636 : )
Chain is 530.
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