Bought the K9 750 early last year, and the suspension has never been right for me, undersprung and just really vague feedback from it. So I decided to start a thread to document the work to get it sorted by myself. K-Tech recommends having a suspension professional do the work, but I hate relying on others for things that I can and should be able to do for myself. And I've got Dave Moss in my backyard and at the track as a safety net if I get in trouble to assist me/take over.
I've got an older '03 R1 that Dave did with the previous owner that is absolutely planted, I want the K9 to be even better so that the only excuse is the rider being old and slow. So a thread to track the journey.
I always want MOAR info when I read these threads that I want to follow, so I'm hoping to keep a high level of detail/photos in here to follow the overkill that will be in this first post. Not sure where my post count needs to be to get links and photos in but I'll get to that level eventually.
Side note, I'll be doing the shock as well, Race Tech Gold Valve Shock Kit 40mm SMGVS 4005 ($145 shipped off ebay) is arriving Friday, Race Tech Rebound Separator Valve SMRS 1212500 ($65) already in hand, and a Race Tech 11.6 spring SRSP 5818116 ($120) is already installed on the shock. But it's never been serviced, so a separate thread for that will be coming when I dig into the shock later this spring.
First off is sorting the springs. I'm 6'4 252#. Bike is needs to be weighed once it's back together tomorrow. The Race Tech site shows that the optimum spring for anybody over 200-ish as 1.12kg/mm, which coverts to 11Nm. Problem is that RT spring options go from 1.0 to 1.4 which is a massive jump.
I found a set of Ohlins springs rated at 1.12kg/mm - 11N - Ohlins pn 004744-11 but the problem is that they measure 5.8mm shorter than my stock springs (stock rate is 9.8Nm).
So if I want to mix springs in the front to get to various custom spring rates I'll need to get my buddy with the lathe to make up some spacers with an additional 5.8mm in length to replace the "JOINT, SPRING UPPER" (see Partzilla link below) which is PN 51175-22D00, $11.70 to keep the Ohlins at a stock length.
The Ohlins are a 36mm X 260mm spring, where stock is 36mm X 270mm. Per Skip @ OrientExpress.com there are a lot of spring options for 36mm X 260mm, and not so much for 36mm X 270mm. Picked up the springs used but never used for $100 shipped from a local guy, they came out of an Ohlins 2006 GSXR1000 cartridge replacement kit (iirc), and you can find them on ebay in the same range or cheaper.
I've got the Traxxion Dynamics extenders installed ("Extended Showa Fork Cap for GSXR") that gives me +20mm to play with. I didn't document the installation of these but I'll prob do so when I tear into the forks over the next month or 2. Straight fwd to install once you understand what is going on.
So yesterday I ordered the K-Tech 20SSK-INT-SHO-15 ($469 w/free 2 day USPS priority shipping from OrientExpress dot com) that should ship out today/tomorrow and hit by the end of the week. Track day at Buttonwillow on Friday then out of town the next week on biz, so I won't be able to get the forks off again until the week of the 13th. But that's real tight since the AFM round 1 opener is the weekend of the 18th which leaves me zero room to f*ck something up as I am bound to do along the way. I might wait till the week of the 20th to tear into the cartridges... We'll see how it goes
Current suspension setup:
1.0kg/mm RT springs currently installed, 20mm extenders installed, 125mm oil height, forks dropped +5mm into the extenders making it +10mm from stock. Sag set to 25mm. Compression and rebound not set, will let Dave set them first thing in the am Friday
Measurement notes: Per service manual stock fork setup is 5mm showing from top of triple to cap seam. Fully extended fork length from cap seam to the top of the the edge where the slider meets the fork bottom is 618mm
403mm from the top of the bottom triple to the edge where the slider meets the fork bottom. Reading in the 'running wide' thread that people are seeing 428mm, length diff in diff years?
stock shock with stock internals that's never been serviced with RT 11.6kg/mm spring. 318mm eye-to-eye (per the book, unmeasured) with 9mm of shims added to the top of the stem of the upper mount. Rider sag at 25mm. As with the forks, no rebound/compression set, will let Dave have at it.
Pirelli Diablo Supercorsa. 180/55 SC2 (hard) rear @ 319.28 radius, 638 diameter, 2006 circum. 120/70 SC1 (medium) front @ 301.67 radius, 603 diameter, 1895 circum
with 9mm shim in rear and forks height at .72 above top triple (as I bought it, no rhyme or reason):
measured as "very straight" by Gerry @ GP Frame and Wheel, can post worksheet later when I can post/link
Goal for this week: install the pair of 1.12 Ohlins springs and set the oil level at 125mm with Maxima 5wt, then hit Bwillow Friday for a track day and work with Dave Moss to get the springs working correctly and confirm geometry. Re-evaluate next steps afterwards.
Couple of reference links to on-topic resources I've found (ugh, can't post links yet, will save them and update later when I can):
's "k tech fork internals installed" thread was the motivation to start this project and go with the more expensive K-Tech
's great "running wide" thread where
along with others provide a ton of setup info:
's DIY fork cartridge holder photos shown in post #6 of the "fork tools" thread in the General Bike forum
In the "06-10 GSXR 600/750 fork Ohlins revalve dampening rod disassemble" YouTube video he shows how to get the valves out of the cartridges, but at the 3min mark (controversially) he cuts the mechanical bump stop out in order to get the rod out of the cartridge to get to the rebound valve, vs the Ohlins suggestion of drilling some hydraulic reliefs to prevent hydrolock while keeping mechanical lock intact. The comments section shows a link to a PDF of the Ohlins cartridge replacement instructions, but the link no longer works
Partzilla microfiche of the "Front Damper" cartridge
comments, suggestions, criticisms welcomed. I'm sure I'll have plenty of questions along the way along with many "learning opportunities" to recover from...