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« on: 29 December 2016, 05:42:28 pm »
Hi Guys,
I have been working on my suspension of late and have done a few significant modifications to both the front and rear ends.
The Rear Modifications:
Firstly I purchased a new Nitron rear shocker, it was built with the correct spring and settings for my riding weight and riding style.
Whilst replacing the shocker I stripped out the linkage and cleaned all the needle bearings and repacked with grease, I was surprised as there was still quite a bit of the original grease still in the bearings, they were showing no sign of wear :-)
The Front Modifications:
For the front forks I purchased a pair of YSS Cartridge Emulators from Wemoto.com.
(YSS Model PD310 for the 2002-2003 FZS 600 Fazer)
To facilitate the operating of the Emulators the Damper Rods need to have more holes drilled through them to overcome the damping effect of them. YSS recommend that 6 X 8mm holes be drilled in them to achieve this.
I went a slightly different route because the damper rods on the 2002-2003 FZS 600 are shorter (190mm) than the earlier Boxeye model (210mm), I was concerned about encroaching on the upper chambers of the forks when the forks are on full compression by drilling the 3 X Double (6) 8 mm holes. 3 X 8 = 24mm, plus 2 X 10 mm minimum spaces between holes = 44mm extension up the damper rods.
(using the centre of the original damper hole as a datum point)
I opted for 2 X Double (4) 10mm holes with one 15mm spacebetween them = 35mm, also to give me a little more lea way I used a fine chain saw file to lower the original 5mm damper hole centre by another 3mm, before drilling the 10 mm holes. 2 X 10mm = 20mm, plus 1 X 15mm space = 35mm, and as I had lowered my starting point by 3 mm, the extension up the damper rods is now 32mm as opposed to 44mm.
The general settings for the YSS Emulators is two full turns in (For lighter (?) togged rider) on the Emulator adjusting screw from initial emulator spring contact with the valve, I set mine to 3 full turns as I am 88-89 Kilos togged ready to ride (14 Stones).
This setting I am fairly happy with although 3.5 turns might have been better coupled with 15 weight Silkoleen Pro Fork oil.
Whilst doing this work I replaced the original Yamaha progressive fork springs with Ohlins 8.5 N/mm linear springs, again more suited to my weight.
The Outcome:
Firstly I am really pleased with the overall improvement with the bikes handling, I have heard terms like ‘The bike feels more planted’ and ‘I feel more confident cornering now’ and that ‘The bike turns in better now’ and to be honest I think the terms that have been used are accurate.
There is a twisty bumpy lane near me (1/3rd mile Rat Run) that has quite a few holes and uneven surface areas (Not fair to call them Potholes) but it’s a lane that I ride at about 35 - 40 MPH because it shakes the crap out of me and because I know that the bumps and pits are coming up I tend to brace myself ready for them (Wrong, I know) and the bumps travel up the forks and give me stick in wrists, elbows and shoulders and generally p----s me off.
I found myself riding down said lane the other day at about 50 mph thinking to my self could go faster,
Of course I was still feeling the bumps, but, they are not jarring anymore and the bike feels much more stable.
Since then I have taken the bike out on the infamous A272 in Hampshire (Petersfield to Winchester) a sweeping road that is great for biking, (Be warned speed cameras are a regular feature along its length)
I have noticed that powering hard out of corners the forks tend to feel as if they topping a bit, so I may need to replace some of the fork oil with a higher viscosity oil or is that lower?, to stiffen/slow up the rebound as bit. This should also help with the compression damping and might mean I have no need to adjust the emulator setting by another ½ a turn.
I have 30 weight Silkoleen Pro fork oil on order. I will replace 100ml of the 15 weight with 100ml of 30 and see how that feels, I understand this to be fine tuning.
I feel that this a worthwhile mod and I also feel that it has been a great improvement to the bike, not just the handling but also the comfort.
The only setback is that without purchasing another set of Damper Rods this is an irreversible mod.
There are often sets of Fazer FZS 600 forks on eBay for sale, and if they are bent in some ways so much the better as they will be cheaper. The stanchions usually bend from the point where the stanchion enters the bottom sliders so the damper rods should be unaffected.
There is always a disclaimer with any information or advice:
Anyone doing this mod, especially the front forks does so entirely at their own risk.
I have only put pen to paper (Finger to keyboard) as an information sharing exercise and not as a guide or a recommendation to anyone.
One last thing.
Some say there are better and financially cheaper ways of improving the rear suspension.
There is a member on FOC-U (DevilsYam) that can supply you with a modified R6 mono shock to fit your Fazer and he will set it up for your weight and riding style, he also will supply the necessary dog bones and fitting instruction for considerably less than I paid for my Nitron Mono shock.
You might find you can save yourself a small fortune.
There is nothing wrong with the Nitron but it is pricey.
There is also a serial front suspension moder on here (Kebab19) You can search for his advice on the front fork mods.
I have used his advice in the fork mods that I have done.
I am now looking forward to seeing those 5/8 inch chicken strips on my back tyre slowly diminishing.
tommyardin