Since the rebuild of my R1 after an off at Donington last year I’ve changed a lot of things, some out of necessity, others from a desire to upgrade. Suspension falls into both categories as it hadn’t been touched since I’d bought the bike 3 years ago.
I’d bought the bike from a guy who weighed around 10kgs more than me, and contrary to a friend with an identical bike who had problems with bottoming his forks under hard braking, I’d never had any such issues, and had wondered whether the previous owner had swapped the springs for some uprated heavier ones? My friend had fixed his issue by having his forks serviced and new springs fitted by an ex Tech3 mechanic, and in combination with changing his OEM shock to an Ohlins, had been very impressed with the improvement in handling and performance the changes brought, so when I told him I was thinking of having my forks overhauled he thoroughly recommended I do so.
Looking round for somewhere to service the forks and check what springs were actually fitted, I found Revs Suspension in Halesowen, a local K-Tech service agent, and after some discussion I took the bike in and had the forks stripped, oil and seals replaced, and the OEM progressive springs replaced with 9.5 weight K-Tech linear ones.
The springs that came out were checked and found to be very light weight 7.5 items, totally unsuitable for my weight, or the previous owners, and they reckoned the reason I’d not bottomed them was because of emulsification of the oil.
Less than two weeks after the work was done I had a chance to check them out at a Donington track day. Unfortunately as so many other things on the bike had been changed, seat position, clip ons, slicks etc, the whole feeling of the bike felt alien and I couldn’t really figure out what aspect of the bike was changing what, and came away a little perplexed that there had been no “quantum leap” of improved feel. One thing I did do afterwards though was to read a load of articles on suspension, and it seems my dislike of front dive at the end of straights had led to me setting the forks up with close to full compression settings to limit this. In fact I’d changed Revs settings back to those I’d had on the old springs as I felt they were diving too much, but reading more about it, it became obvious that I’d made a mistake and that dive is good, so I changed the settings back to theirs, and lo and behold at the next track day the feel from the front, ease and speed of turn and feedback had improved, which led to the next problem………, the rear.
The more I rode the bike the more I got the impression the front and rear weren’t quite working together, and knowing the forks were fine, attention turned to the rear OEM shock. I knew something was odd when I could only get correct sag settings with the rear preload on full, and although having it set that way allowed me to drop my times by two seconds a lap, clearly it’s not ideal having it set up so hard. My diagnosis that the rear spring was too soft for my weight was backed up after a chat with 100% Suspension at Donington. I described the handling issues I felt I was experiencing to them, and after the rear was bounced a few times and settings checked, it was confirmed that indeed it was too soft, and that Yamaha were known for putting soft springs on this model. I was advised replacing the spring only was pointless given the age of the shock, so armed with the knowledge that I needed to spend some money to fix the problem, it’s fast forward to the end of August, and I’m on my way up to TW Suspension Tech in Preston to have a brand new Bitubo XXF31 shock fitted.
STORY TO FOLLOW:-