ElectricMotorcycleForum.com
Makes And Models => Zero Motorcycles Forum | 2013+ => Topic started by: rayivers on August 17, 2015, 08:52:51 PM
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UPDATE: I've made a bunch of changes to spring specs etc. in the 'FastAce fork oil change / spring replacement, part 2' thread (http://electricmotorcycleforum.com/boards/index.php?topic=5323.0), which you might also want to check out if you're planning to work on your FastAce forks.
After living with the Fox shock & new spring for a while, the FastAce forks seemed increasingly harsh in comparison. The rear was hooking up & tracking straight, but the front end was dancing around and deflecting off everything, and only compressing about 6". After the work below, the bike stopped bouncing and just rolled over everything instead, holding the desired line much better. I found myself deliberately aiming for the nastiest rocks & roots, but instead of being thrown off line as before, there was just a quick 'buh-bump' with almost no direction change at all. The bike feels more stable and 'planted' now, with @ 8" of travel visible on the sliders (I haven't felt the forks bottom yet).
Here's a diagram I put together that's close to what I found inside - it looks like the fork is a 43mm 'cosmetic copy' of the 47mm '04 Honda CR250 Showa forks, with rebound-up internals from the '95 CR250 43mm Showas:
(http://i399.photobucket.com/albums/pp74/rayivers/FastAce%20APX05RC%20Fork%20Diagram.jpg)
What was done: I replaced the OEM 24.8 lb/in (.44 kg/mm) springs with 18.0 - 23.0 lb/in (0.32 - .41 kg/mm) progressive springs from Cannon Racecraft, along with 7mm preload spacers & Bel-Ray HVI 3W shock oil. Sag went from 20mm (static) 38mm (race) to 32S 56R, and every aspect of the fork improved. The adjustment clickers also became usable, instead of just staying at minimum damping as before.
(http://i399.photobucket.com/albums/pp74/rayivers/OEM%20amp%20Cannon%20Springs.jpg)
Spring Dimensions (OEM): 16.56" / 420mm OAL, 1.46" / 37mm O.D., 1.10" / 28mm I.D., 32 coils
(http://i399.photobucket.com/albums/pp74/rayivers/7mm%20Fork%20Spacer.jpg)
Spring Spacers: 1.00" I.D., 1.46" O.D., .28" / 7mm max thickness, aluminum (machine shop), or...
NF14502 nylon washers (1.45" O.D. x .99" I.D. x .12" thick, www.non-ferrousfastener.com (http://www.non-ferrousfastener.com))
Prep: I put the bike on the stand, removed the bars & risers together (riser bolts use 7mm Allen keys), then slightly loosened both fork caps, front axle, & brake caliper bolts while the front wheel was on the ground. To minimize fork-cap damage, I used a modified 34mm Proto impact socket w/.012" shim, aluminum tape, and plastic guard made from an aerosol can lid:
(http://i399.photobucket.com/albums/pp74/rayivers/Proto%20Socket.jpg)
I then propped up the front end at the fender bolts, and removed the front wheel, caliper, and both fork legs.
Fork Cap / Spring Removal: Adjust the rebound clicker to about 10 clicks CCW from full CW, then unscrew fork cap from leg, slide cap/spring up slightly, and slide a thin 17mm open-end wrench (I used one from an old Honda tool kit) between the spring coils to fully engage the two flats on the inner shaft's locking collar. These flats round easily & require a fair amount of torque, so use the widest thin wrench you can find. ;) While holding the fork cap with the socket, unscrew the locking collar until it bottoms on the shaft threads and resistance is felt, then continue to apply force to unscrew cap from shaft. Leave rebound clicker & slotted setscrew exactly where they are, and the cap may go right back on later. With the cap off, remove the springs (the center shaft may slide down into the fork, no biggie). NOTE: I didn't see any Loc-Tite on anything I worked on.
(http://i399.photobucket.com/albums/pp74/rayivers/Socket%20amp%2017mm%20Wrench.jpg)
Oil Change (the forks do NOT have to be disassembled further): I set up a long steel rod with about 6" hanging over the bench edge & the other end weighted. I pumped out as much oil as possible into a pan underneath the rod, then hung the fork leg on the rod to let the rest drain (it took a while). The LH leg had @ 400cc, RH leg 360cc. The oil seemed like maybe 10W, black & 'pearlescent', and looked/smelled a lot like some 70's graphite-based fork oil I have. After a Web search of 43mm-fork oil levels (the lowest I found was 378cc, highest was 410cc), I decided on 400cc of Bel-Ray HVI 3W oil. NOTE: this was for a '14 2.8 FX w/light springs; the 5W HVI might be a better choice for a 5.7 w/OEM springs, although the 3W should work well too.
After flushing out any remaining OEM oil with some old HVI 3W, I poured in the new oil slowly, then worked the shaft up/down repeatedly. At first there was cavitation noise, but after many up/down movements the noise stopped and the shaft had full damping in both directions. The oil level was 130mm from the outer tube top when it was aligned with the top of the center shaft.
Spring / Cap Replacement: OEM or straight-rate springs can go back either way, but progressive springs must have the 'soft' side down so the 17mm wrench can be used again up top. The center shaft will want to slide down inside the outer tube, so I angled the fork leg quite a bit to put some side friction on the center shaft while the spring was slid over it. Once the spring was in, I used the 17mm wrench to snag & move the center shaft up more. I then put the spacer inside the fork cap and screwed the cap onto the center shaft (the spring needs to be compressed with the wrench in place, kind of a PITA). The cap clicker's lower end is basically a super-short flat screwdriver blade which engages a slotted setscrew in the center shaft's I.D.; if the clicker and setscrew weren't moved during the fork work, the cap might go right back on to full thread depth - but I'd assume the worst and screw the cap on slowly & gently, and if it stops moving early try rotating it and/or the clicker back and forth a bit until the clicker blade engages the setscrew slot (if the clicker starts clicking while the cap is being installed, either the clicker blade is jammed against the setscrew or the adjuster needle is bottomed; try backing out the clicker a half-dozen or so clicks). Once cap is on (be sure air venting screw is tight!), invert & rotate fork legs once to oil spring & outer tube, then return quickly to normal cap-up orientation so cartridge stays full of oil.
Misc: The rebound-adjuster setscrews push against long aluminum needles. The needle tapers are short and roughly machined, so it's no wonder they have poor action over a limited range. I smoothed and polished the tapers a little which seems to have helped a bit, and may try having custom needles made at some point (although these are working great with the 3W oil).
(http://i399.photobucket.com/albums/pp74/rayivers/Fork%20Cap%20amp%20Setscrew.jpg)
(http://i399.photobucket.com/albums/pp74/rayivers/Rebound%20Adjuster%20Tapers.jpg)
Torques used:
Handlebar clamps 15 ft/lb (M8)
Handlebar risers 25 ft/lb (M10)
Triple clamps (all) 15 ft/lb (M8)
Fork caps 15 ft/lb (M46)
F caliper bolts 18 ft/lb (M8)
F axle end cap 15 ft/lbs (M8)
F Axle clamps 9 ft/lbs (M6)
Ray
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This is a great write-up, thank you! It looks like you have the 2014 Zero FX for reference by forum search.
Since I have not done a fork oil weight change (just a straight OEM-recommended replacement on another bike model), would you say that the fork oil can be replaced with a heavier weight without an intentional spring upgrade?
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No problem, Brian - hopefully it will be of help to the pre-'15 Zero owners. It took me a while to get up the courage to pull it apart - I kept thinking some irreplaceable Chinese part might break and I'd end up kicking myself - but it really wasn't too bad, and the results were beyond my expectations.
If your springs seem OK to you, there should be no real need to change them; just an oil change should be fine. My forks felt very stiff and harsh and the clickers had little effect, so I knew I needed both softer springs and thinner oil - but if they felt 'squishy' & underdamped, I'd definitely have tried different (and likely slightly heavier) oil. The hard part is figuring out how heavy the OEM oil was, as a starting point... it's definitely way thicker than the 3W Bel-Ray.
In light of the way my fork worked before and after - and the big difference in OEM oil levels between legs (my seals don't leak at all) - I'd highly recommend replacing the original FastAce fork oil ASAP, providing one is comfortable with the work involved (I shouldn't think there'd be any warranty issues). I don't know what kind of oil was in there, but the 'scraping' feeling the forks had is gone, and they move smoothly now with little effort.
Ray
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Ray, Do the fork caps have an air-bleed screw? Regarding the original springs and fork performance, if built up air pressure isn't released(apparently it should be done with front wheel off the ground), the air acts as a spring, and they won't sag as low as before.
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Ben,
Yes, the caps have bleed screws above the rebound adjusters. Before the fork work one of my caps would make a slight hissing sound when loosened and the other did not, probably because of the 40cc difference in oil amounts. I rode this morning and just loosened both again, and they both released about the same amount of pressure.
I've been looking for all-black fork bleeders, these are the closest I've come so far:
http://www.amazon.com/gp/product/B006NMWQVK/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A9NJNMT9ZTSIP (http://www.amazon.com/gp/product/B006NMWQVK/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A9NJNMT9ZTSIP)
Ray
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I've used quick air bleeders before, they sure make the job easier, but haven't got any on my bikes at the moment. I rely on the air space to stop my forks from mechanical bottoming, and I wonder if the quick bleeders would affect that, whether they allow air to slip through; I should try some again and find out.
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I bet the peak air pressure gets pretty high when the forks are really compressed, and if the bleeders weren't designed to withstand that... yuk; you'd probably get oil all over & around them. My bleeder screws always spew a little oil when I unscrew them even with the bike stopped, and continuous quick-bleeder leakage during riding would be much worse, with all that oil flying around in there. There are a bunch of different types out there, I'll look around for some reviews.
Ray
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Just a quick update after a dozen dirt rides...
The springs have bedded in nicely, and the forks move smoothly without binding. Current sag is 32mm static / 67mm race, a little high - so the next set of springs will be 19.0 - 24.0 lb/in (0.34 - 0.43 kg/mm) progressives, all other specs unchanged.
All the clickers work better with the thinner 3W oil, but on my 2.8 they still feel best at the minimum (full CCW) position. 3W with the OEM springs should work fine for a 5.7, but I'm going to try Red Line LikeWater fluid next time (@ 1.5W, the thinnest available). If that doesn't help enough, the next step will be machining the needle tips to a 33° angle (stock is @ 34°). I could be wrong, but I think the shim stacks are set up quite stiff on these forks. As soon as the clickers start restricting the stack-bypass flow, damping increases greatly.
About the rebound clicker: the full-CCW position is the setscrew hitting the cap, while I believe the full-CW position is the needle tensioning spring bottoming (the needles show no marks from contact with an orifice). If this is the case, counting clicks CW from full CCW is probably more precise than the usual back-from-full-CW count.
Ray
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When I had the oil replaced on my 2002 Yamaha FZ1, the oil used was Yamaha 0-weight :o oil on that fully-adjustable cartridge-type fork.
At least that was what my dealer's service department said they used. ???
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Wow, 0W fork oil - that's great, thanks for the info. I'll try that instead of the Red Line.
Ray
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Please share the progressive spring P/N I did not see a option on the Cannon Racecraft application chart.
Thanks Jerry
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These springs are 100% custom winds - you won't find them in the Cannon application chart.
The Cannon P/N for the springs mentioned in the beginning of this thread is 37420 .32-.41 (37mm O.D., 420mm overall length, .32 kg/mm initial rate, .41 kg/mm final rate). The transition point between rates is at 90mm of travel. These springs work fine, but their sag numbers are a bit too high so I had a 2nd set made, which I installed on the bike last night (haven't tried them out yet).
The Cannon P/N for this 2nd set of springs is 37425 .34-.43 (37mm O.D., 425mm overall length, .34 kg/mm initial rate, .43 kg/mm final rate), transition point at 76mm.
Top spring is 1st wind (37420), bottom is latest one (37425):
(http://i399.photobucket.com/albums/pp74/rayivers/Cannon%20Fork%20Springs%201st%20set%20on%20top.jpg)
Once I have a few rides on the new springs I'll update this thread.
Ray
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Hay if your still around could you hook me up with some links to where I could buy this parts?
Sent from my XT1585 using Tapatalk
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Sure - click on the yellow-highlighted link in the 1st sentence of this thread to take you to the Part II fork thread, then click on the 'Cannon Racecraft' link there to get to the Cannon web site.
Ray
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Hello Ray,
I`m new in this forum, please excuse my poor english. I`owner of a Fx 2013. I have a question regarding Oil-Chance in the fork. Is it possiple to loose the nut at the bottom and fill after that Oil in the small screw at the top side with a needle? best regards Rolf
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Hi Rolf,
I think the 2013 FX Fast Ace fork has the same oil-change procedure as the 2014 fork. If the oil level is low you can add oil through the top screw hole, but to get the oil out you must remove both fork legs. :(
The large bottom nut is the compression-damping valve & adjuster. I would not loosen this nut with the forks on the bike!
Ray
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Hello Ray,
Thank you for the quick information and the warning. For the moment I will do nothing - to keep me out of trouble. Perhaps in winter the time will come.
Greatings from Germany
Rolf
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Ray,
I read this thread multiple times (THANKS!!!) and decided to change the oil on my 2014 SR yesterday.
One question, is it really necessary to remove the spring cap just to change the oil? I did not remove it, I just pumped the forks until it was no longer dripping, then used a tube to feed in the new oil between the fork tube and spring.
On my bike the right fork had 300cc, the left 325cc, I followed your advice and used 300 cc Redline LikeWater/25cc Triflow.
I pumped the fork leg until it moved smoothly and no cavitation could be felt/heard, then screwed the cap back on.
After assembly I pumped the forks up and down and bled air out using the new Outlaw Speed bleeders until I could no longer hear air pressure release when I pushed them. I'll ride it today and see how its working.
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Hello all,
I make an answer on this old topic since it corresponds almost to my need!
I'm French rider, so my English is bad, sorry for that.
After a fork seal linkage on my ZERO S 2014, I decided to dismantle it in order to pick the seals and dust seals references... I will provide they here after (simpler way to order them).
I've a concern about nut hidden by the spring since it has been damaged - fork already opened! - but I will get by, certainly with the string compression before put a wrench.
Since it seems someone have been already changed oil here, can you provide the oil level you measured from the top of the tube?
Another feedback about oil type to poor inside?
5W could be ok?
Thank you,
Vincent.
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I came across this exploded diagram of the FastAce fork in my computer files that might interest you.
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Hi Richard,
thanks for the answer.
Yes, I found already it on the forum, certainly your one.
I opened the two legs, with spring compression in order to have a full access to the nut... (the one of the left leg has been very damaged by previous 'mechanics'**).
I didn't arrive to measure the level of the free surface of the oil... And, from my point of view, it's impossible to do on this fork ??
WIpe seal is a 43 x 54.3/59 x 6/14.5 on FASTACE brand.
Seal has a reference NR9990 and sizes seem to be 43 x 54 x 11, triple lips
I have some difficulties to find on the net the right ones, I will try a first ones...
** Since I just discovered the fucking job of my dealer's mechanics when I changed bearing... never seen this kind of job, horrible... I tried to place the new ones with some ScelBlock on left side... So, I prefer to not go to the shop, since I'm very angry...