I'm looking at suspension upgrade options for my '13. I understand that rear shock choices are the same as those for Gen II bikes, but I'm still trying to figure out what is available to upgrade the forks.
Any thoughts?
Any thoughts?
Gen III Non-ES fork upgrade?
- Thread starter DaJudge
- Start date
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JamesK
Got to ride
Traxxion Dynamics AK-20 cartridge inserts, accept no substitute.
https://www.traxxion.com/AK-20-Axxion-Cartridge-Kit/
https://www.traxxion.com/AK-20-Axxion-Cartridge-Kit/
They don't list a kit for the gen 3.Traxxion Dynamics AK-20 cartridge inserts, accept no substitute.
https://www.traxxion.com/AK-20-Axxion-Cartridge-Kit/
MCRIDER007
Well-known member
They have a AK-20 kit for the GEN3s because I talked to them about converting a set of GEN2 AK-20s to fit my 13A. It would have cost $250 plus shipping in both directions. After a lot of back to back rides with my 08 with the GP Suspension front end, I decided there probably would not be enough of a improvement to justify the cost and sold the AK-20s. I think that changing the forks on the GEN3s might be worth the cost if you spent a lot of time on very rough roads, otherwise the OEM forks perform very well.
Thanks guys.
I don't spend much time on rough roads. Just looking for good handling characteristics.
I'm pretty well convinced that the least I'll be doing is upgrading to heavier, linear fork springs (new/better oil, seals and lower bushing whilst at it) appropriate for a 250# solo rider like me along with an aftermarket rear shock likewise sprung.
It's a shame that I'm not within decent riding distance of either GP or Traxxion. I've yet to get a line on any good suspension shops in Texas although I'm sure that a few must exist in a state this big.
I live only 200 miles from GP and still would send my stuff in. IIRC, it was $60 each way when I last sent my forks in for service.
They have one for the Gen 3. I had them installed in mine back in Sept 2013, it was the first Mod I did to my bike. The AK20s along with a Penske on the bike REALLY transforms the bike.They don't list a kit for the gen 3.Traxxion Dynamics AK-20 cartridge inserts, accept no substitute.
https://www.traxxion.com/AK-20-Axxion-Cartridge-Kit/
No doubt the AK-20 cartridge kit (or the GP 25mm cartridge kit) would be the best in FJR front end sweetness. Unfortunately, I'm not in a position to drop $1100+ into upgrading my forks (which would mean over $2K into the overall suspension package).
Let's say that I decide to pursue stiffer/linear springs and re-valving (if possible) using the one-sided factory '13 forks. I looked at the factory service manual which shows, of course, that only the right fork has the damper adjusting rod/valve/spring. That being so, what's inside the left fork damper assembly? Are there any internal parts, like non-adjustable compression/rebound valving, in there that can be upgraded? Is the left fork essentially a pogo stick with some oil inside for lube and rust prevention? Not surprisingly, the service manual gives no clue. Has anyone been down this upgrade road?
Let's say that I decide to pursue stiffer/linear springs and re-valving (if possible) using the one-sided factory '13 forks. I looked at the factory service manual which shows, of course, that only the right fork has the damper adjusting rod/valve/spring. That being so, what's inside the left fork damper assembly? Are there any internal parts, like non-adjustable compression/rebound valving, in there that can be upgraded? Is the left fork essentially a pogo stick with some oil inside for lube and rust prevention? Not surprisingly, the service manual gives no clue. Has anyone been down this upgrade road?
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Per Traxxion the internals on the left fork are the same as the right fork (looking at the parts diagram will also confirm this). You can purchase part "Bolt, Cap 2
1MC-2311J-00-00" and put it on the left fork and have adjustable Rebound Damping for the left fork. I had Traxxion do this when they installed my AK20s.
MCRIDER007
Well-known member
Per Dan at Traxxion and Barry at GP Suspension, the left cartridge is "dead" with no damping at all, that is why the Gen2 AK-20s have to be modified to fit the Gen3s. GP suspension claims they were able to improve the damping in the right cartridge by changing the shim stacks (which isn't possible on the Gen1 and Gen2s) but it was either a very small improvement or not enough profit because they are not selling a fork kit for the Gen3 right fork. They are selling total replacement 25mm cartridges with rebound damping on one side and compression damping on the other side (same damping arrangement as the Gen3 AK-20s).
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Thanks MCRIDER07. I was hoping you might show up. It looks like us Gen3 A guys are stuck with either the full-meal deal (new cartridges) or a simple re-spring for rider weight and new oil. Did either shop say anything about the stock fork valving on the Gen3 or what oil brand/weight they preferred?
As far as you know, are the linear springs for the Gen3 forks the same as Gen2 or different?
Any suggestions about seals/bushings for these forks? What's the best way to figure out what length spacers I'll want to use with the heavier (probably 1.0kg) springs?
I'm coming up on 3 years old and 12K miles. I figure I'm due for a fork oil change anyway since I don't believe that the original owner had the forks serviced. Last time I serviced/re-sprung forks myself was several years back on an '06 YZ450F dirt bike (which was dual cartridge), but hopefully it will come back to me. Sounds like a good project for over the holidays if I can get the parts needed.
MCRIDER007
Well-known member
According to the FSMs, GEN2 fork springs are .86kg and GEN3 fork springs are 1.02kg so unless you are experiencing excessive sag or nose dive under braking there shouldn't be any reason to change the springs. To compare spring rates, GP Suspension recommends 1.0kg springs and Traxxion seems to normally go with 1.1kg springs.
Fork oil is easy, use 5wt oil or 85/150 suspension fluid. Honda's SS7 is also a very good 5wt fork oil and you can buy it for about $6 a pint (takes 3 pints).
At 12K miles you shouldn't need new seals or bushings. If you do change them, stick to Yamaha parts.
If you feel that heavier springs would be an improvement you probably should experiment with using more damping before you change springs. Do the rebound damping first since changing the rebound damping will also have a lesser impact (in the same direction) on the compression damping.
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I really appreciate the good info. I didn't think of looking in the FSM for the stock spring info, but now that you mention it..............
Based on that, I'll see what a fork oil change, bumping the rebound dampening a click or two, and a rear shock upgrade does.
From what I see, the 3rd Gen (non-ES) fork springs are dual rate springs, very similar to the old 1st Gen springs. The first 67.5mm are a softer .85 kg/mm and the second half of the spring is a stiffer 1.02 kg/mm. Normal loaded sag is ~45mm or so, and the spring installed pre-load is probably 5-10mm, so that means that when you ride down a smooth road you are still on the softer .83kg/mm spring until you hit anything that compresses the fork more than 10mm, then you would be into the stiffer 1.02 kg/mm spring.
For comparison and historical purposes:
1st Gens thru 2003 had dual rate springs
K1 = 91mm @ .799 mm/kg, and K2 = 91 - 135mm @ .999 kg/mm
2004 and 2005 1st Gens also had dual rates
Same K1 as in '03 but K2 was stiffened to 1.10 kg/mm
All 2nd Gens have single rate .85 kg/mm springs.
For comparison and historical purposes:
1st Gens thru 2003 had dual rate springs
K1 = 91mm @ .799 mm/kg, and K2 = 91 - 135mm @ .999 kg/mm
2004 and 2005 1st Gens also had dual rates
Same K1 as in '03 but K2 was stiffened to 1.10 kg/mm
All 2nd Gens have single rate .85 kg/mm springs.
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MCRIDER007
Well-known member
Fixed the Gen2 rate for you.
I haven't looked at the '13 springs yet but they don't feel like there is a transition point, they feel like 1.0kg springs all the time. Ditto for my S10, it most definitely came with dual rate springs but it appears that the transition point happens within the initial sag and they felt like they were (I replaced them with .90kg linear springs) on the stiff (1.2kg) portion of the spring all the time.
Bottom line was for me the 05 springs seemed to be very under sprung, the 08 springs were better but still too light, and the 13 springs seem just right.
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gumba
Well-known member
I have a 09 with 013 forks. I put the 09 forks on the 013 with AK-20s. Both scooters have Penskes. I'm always amazed when I take the 09 out and the excellent feel. If I were starting from scratch, I'd go 013 forks with a Penske. The 013 forks are not half bad.
One thing that is not clear in the FSM spring specs is whether the K1 stage is "as installed" or on the raw uncompressed spring.
One big difference between the 1st Gen 2 stage spring and the 3rd Gen 2 stage spring is the length of the 1st stage is significantly shorter on the 3rd Gen, so it may be that the pre-load and bike weight (sag) takes up nearly all of the softer spring. If that were the case they would feel much more like the higher spring rate all of the time.
But there is good reason to be dubious of the FSM specs. For instance, on the 3rd Gen ES they claim to have two single rate springs with 2.0 kg/mm rates. That is ludicrous. Perhaps they meant the sum of the two is 2.0 kg/mm, which would be much more believable, but why change from the normal method of spring rate spec now?
PS - I went back and fixed my Gen 2 typo. Thanks for the heads up, not that it really mattered much.
One big difference between the 1st Gen 2 stage spring and the 3rd Gen 2 stage spring is the length of the 1st stage is significantly shorter on the 3rd Gen, so it may be that the pre-load and bike weight (sag) takes up nearly all of the softer spring. If that were the case they would feel much more like the higher spring rate all of the time.
But there is good reason to be dubious of the FSM specs. For instance, on the 3rd Gen ES they claim to have two single rate springs with 2.0 kg/mm rates. That is ludicrous. Perhaps they meant the sum of the two is 2.0 kg/mm, which would be much more believable, but why change from the normal method of spring rate spec now?
PS - I went back and fixed my Gen 2 typo. Thanks for the heads up, not that it really mattered much.
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