Since putting the GSXR1100 engine into the bike, I have not been happy with the suspension. Or rather, the exhaust has hit the deck a few times, and the lack of weight and very aggressive stance have caused a few bum clenching moments. It’s mostly made the bike harsh and skittish. Common sense would say that the spring rates are probably now too high, and the extra weight of the GSX engine would have made the bike feel plush in comparison.

With 120 hp, the bike is traveling much quicker, is being asked for more of everything, and the geometry is just not helping. The geometry is overly aggressive and needed dialing back a little. I plan to add height to the rear (internet research suggests, up to 20mm) but what to do with the front? Well, we’ve dropped the height lots – see my previous blog post on the topic.

So with 50mm fork extensions to play with – before deciding on the final level, it was a simple case of getting them installed. This would have been far easier if it weren’t for the fact that I have installed race tech springs and preload spacers. With the spacers ever so slightly wider than the stock internals – having removed the inner assembly, I fitted the lower extension but couldn’t just drop them back through the upper extension! They were fouling – being slightly too wide in diameter.

We got them fitted (thanks to Phil at Cambridge Motorcycles for the loan of a spring compressor and his body weight. As Phil compressed, I removed the cartridge top, released the compression, dropped on the upper extension, and then recompressed and re-fitted the cartridge. It was a relatively simple once we worked it out. Some fresh oil and oil height set to TL1000 spec.

Once they were back in the bike, with a 25mm addition to the front ride height, a spirited 50 miles suggests it was the right decision to extend the forks. It needs rear ride height, and I could probably lower the front 5mm further – but I’ll leave it as is for now.

IMG_8783.jpg

The attitude looks fine … amazing how a small change can have such a dramatic effectSo overall the original forks were 812mm, we moved to TL1000S forks – 740mm. A change of 72mm, and then reduced ride height further with a 25mm drop for the change in wheels to 17inch. We’ve added 25mm with the extensions, so overall the front is still 72mm lower! Even with those calculations, I am not convinced we’ve really dropped the front that much. Looking at the photo above against a standard bike it is obvious, based on the line of the bottom rail and the fairing, that we are lower overall,  and the front is still at a more aggressive angle. Note the original bike is on its centre-stand. I reckon some adjustable rear shocks (making some new bottom clevis mounts would be easiest) would be the way to go – I will probably aim to get at least 10-20mm on the back shocks. Back in the day CB900F shocks were the way to go .. they were 350mm long as opposed to 331mm of the SU143 Ohlins – so that sounds like a plan!

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AfterIMG_8783

Stock Bikesuzuki-gsx-1100-s-katana-7

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