Because of age-related arthritic joints making conventional gear changing painful, in September 2017 I bought an ex-Japan 2014 model with just 4,500km on it. The SD has ABS and a dual-clutch transmission which can be used as an automatic and as a trigger-operated 6-speed manual.
In mid Dec 2017 I rode the bike to New Plymouth for suspension specialists, Kiwi Suspension Solutions (KSS) to upgrade the suspension for my weight and to suit the often-ngarly-surfaced minor-roads where I prefer to ride. A dual-purpose bike would probably be better for this but they are too tall for me now because of arthritic joint-stiffness.
KSS have transformed a few past bikes for me so going to them this time was the obvious move. Chief actor there, Robert Taylor, is a hard-working and no doubt demanding boss, and a real professional for suspension work. He’s also a man who doesn’t suffer fools yet continues to accept me as a customer! Particularly as I’m probably a PITA with the very fussy way I want my bikes to ride like a magic carpet over even the worst surfaces.
Before this upgrade I’d rated the stock Honda suspension at only 4/10 because of it’s harshness and generally poor compliance. The ride to NP was punishing for my arthritic back and hips and while the return ride with a Nitron shock and Cogent DDC valves installed was very much better, I still rated it at no more than 8/10. With-rider sags at both ends had been pathetically poor but now had become a perfect 40mm so maybe I should’ve been satisfied with that, but since KSS had brought my other bike, a Buell XB12Ss, to what I rate as 11/10 I was hopeful that better than 8/10 could still be achieved on the SD. And so it has transpired.
Because Wendy-wife and I were driving to NP anyway, this time I took just the fork legs and rear shock for further tuning.
The first procedure by KSS had comprised of re-working the fork internals with appropriate single-rate springs, modified damper-rods etc. and Cogent DDC valves. The oil type and level were also set very differently from stock for better air-springing effect. At the rear, a Nitron R2 shock was fitted. This had been ordered from England a month or so before for my model NC, my weight and load-intentions, my mostly pretty-cruisy riding style, but on often imperfect road surfaces.
Apparently Nitron supply the shocks set up for the specific bike model and then spring them to suit the payload. If that doesn’t satisfy the customer, KSS as NZ agent has the right and ability to tune the unit further, which is what KSS did this time.
Maybe because I showed more than average interest in what happens inside suspension components, or because I can be a PITA if ignored, Robert agreed to my being present to watch proceedings, and what a wonderfully instructive few hours that proved to be. Not only do KSS have an impressive setup and an amazing array of equipment, including an all-important suspension dyno, Robert and his off-sider, Dennis Shaw are true suspension gurus with a lot of experience with road and race-bike suspension development. I was surprised to learn that road riders make up about 75% of KSS’s work. This is not just a race-bike specialist firm, but also there for the likes of road riders like me who realise that they need better suspension performance than manufacturers of road bikes can usually provide, and are prepared to pay for it.
This time the goal was to achieve even more compliance by re-tuning the damping, especially the high-speed compression damping which is so critical for coping with harsh, abrupt bumps. The forks were dismantled completely, slightly-lighter springs fitted and the shim-stacks in the DDC valves altered.
The Nitron shock and compression adjuster were de-oiled and de-gassed and then dismantled as far as necessary to alter the main-piston shim-stacks and for Robert to make another couple of adjustments which I didn’t really understand. Spring and pre-load were not altered and a dyno run done prior to dis-assembly gave a reference force-curve graph. Once re-assembled, re-oiled and re-gassed using special equipment, further dyno runs showed nicely progressive response to different damping settings and then Robert re-zeroed the compression adjuster so that it will operate most effectively in the range where compliance is most critical, but consistent with proper “pressure balance” as Robert explained emphatically. Now I understand why truly-expert suspension work cannot be done without a suspension dyno if endless trial and re-adjustment work is to be avoided.
To illustrate how far KSS will go when necessary to satisfy the more demanding (read infuriating!) customers, all this second stage work was done without further charge. All I had to fund was the oil used.
And the outcome of all this? Once the bike was in one piece again I measured the with-rider, load and full fuel-tank sag readings again. The front sag was now 41mm while the rear was predictably still 40mm. Ideal. As Robert recommended, I backed off the rear rebound until getting almost a bounce under a static push-down test. That proved to be -13/24 so I set it at -12/24 for the test ride and the rear compression at -10/16 clicks. The first ride around my 100km ‘test circuit’ showed that the latest work was not in vein and now deserves a solid 9/10 for the forks and 11/10 for the Nitron rear. Why only 9/10 for the forks? Because they must always remain inferior to the USD Showa 43mm ones on my other bike, a Buell XB12Ss. For the second 280km ride on different roads that same day I upped the Nitron compression to -12/16 and the rebound to -14/24 on the basis that if it felt good before, more of everything should be even better. Certainly it felt no worse.
Is the upgrading finished yet? Not quite. I’d like to see if the forks can be made better than 9/10 by improving further their high-speed compression response so I will remove the DDC valves and send them to Robert for more of his magic. Under front-only braking hard enough to activate the ABS the dive feels fine and 115mm of the 120mm stroke is being used. Currently 7.9N springs, Putoline 10W oil, oil level -140mm.
So, unless you are lucky enough to be of whatever weight the designer specified the stock suspension for, then avoid riding a similar bike which has had an expertly upgraded suspension job or risk dissatisfaction. Remember that no amount of preload adjustment can alter the spring strength, only the ride height. The spring strength needs to be matched to your payload weight for ideal performance.
The Nitron shock includes a small range of height adjustment which I would make use of to raise the rear and so reduce the overly generous fork rake and trail on this bike a little, but already the bike’s height is enough to make mounting and dismounting a bit difficult for my arthritic hips. The use of decent single-rate fork springs has reduced the excessive original sag of 54mm too, which hasn’t helped with mounting but that is still a good trade-off.
Given what I saw in the KSS workshop, it’s clear that Robert and Dennis get to re-tune even the best suspension offerings, this for the same basic reason that nothing can match great components, expertly personalized.
Forget more power, louder exhausts and bling until your bike gets good tyres and personalized suspension.
Honda NC750 SD Suspension Upgrade
