Fork Interchangability

[deanw]

Has anyone looked at interchangability of forks between generations?

If I picked up a set of Gen I or Gen II forks and had them rebuilt, are the attachments any different that they wouldn't just slide onto my Gen III?

Or is all this still out there?

 

[Ignacio]

I've attempted to cover this in the FJR Comparison Matrix. 2003 Gen 1, not compatible with 2004 & 2005 Gen 1. Gen 1 not compatible with Gen 2/3. Gen 2 likely compatible with Gen 3...although I understand the internals of the Gen 3 were changed significantly.

 

[deanw]

"Likely compatible"... right. So I'm pioneering here, but I can forget the 2004 forks on ebay. Got it.

OTOH, if I picked up a complete 2006+ left fork leg, it's a valid experiment. Hm. Guess I'll keep my eyes peeled.

 

[Ignacio]

"Likely compatible"... right. So I'm pioneering here, but I can forget the 2004 forks on ebay. Got it.
OTOH, if I picked up a complete 2006+ left fork leg, it's a valid experiment. Hm. Guess I'll keep my eyes peeled.

It's helped us a lot...sorry I can't make it more definitive, but it's validity comes often from pioneers reporting back like yourself on actual experiences, those that go over fiche and part numbers with a fine-tooth comb, and other subject matter experts.

 

[mcatrophy]

...OTOH, if I picked up a complete 2006+ left fork leg, it's a valid experiment. Hm. Guess I'll keep my eyes peeled.

Think you'll probably need a pair. The '13's forks are not symmetrical, something like one contains the springing, the other the damping, or some such. So a single Gen II fork won't directly replace a Gen III one.

 

[yamafitter]

The Gen III forks would have to be completely swapped with the forks from the Gen II for the reasons stated. The valving internals do not match so no mixing allowed. I have not heard of any of the suspension shops offering upgrades to the Gen III forks but that is not to say they are not out there.

I'm waiting on Mother Yamaha to release the AS version with active suspension to the North American market myself. My sources say this may happen sooner than you think.

 

[Bungie]

Something I've noticed, and it may just be a visual thing, but I'd swear that the Gen3 forks are of a smaller diameter than my Gen1 forks. I'll get my thumb out tonight and measure.

oh, Yamaha has done a stellar job on the 13's suspension setup. Soaks up the bumps and doesn't beat you to death so it still handles nicely in the turns. Their is near 0 stiction from the front forks. Can't say how it behaves at 9 or 10/10ths. But at any sane street pace, VVG!

 

[MCRIDER007]

...

OTOH, if I picked up a complete 2006+ left fork leg, it's a valid experiment. Hm. Guess I'll keep my eyes peeled.

Think you'll probably need a pair. The '13's forks are not symmetrical, something like one contains the springing, the other the damping, or some such. So a single Gen II fork won't directly replace a Gen III one.

Both GEN3 forks have springs and both have internal cartridges so there isn't any reason to think the left fork does not have compression and rebound damping. The internal damping between the GEN2 and GEN3 forks may be different so if you mixed forks you may need different settings for the damping to be the same.....which really isn't important because the damping between the forks is probably going to be different on GEN3 forks anyway.

There really isn't any reason to replace the GEN3 left fork with a GEN2 fork unless you are also going to change the internals on both forks and that should work without any other modifications.

Both GP Suspension and Traxxion say they have a solution to upgrade the GEN3 forks but haven't given any details.

 

[deanw]

The Gen III forks would have to be completely swapped with the forks from the Gen II for the reasons stated. The valving internals do not match so no mixing allowed. I have not heard of any of the suspension shops offering upgrades to the Gen III forks but that is not to say they are not out there.I'm waiting on Mother Yamaha to release the AS version with active suspension to the North American market myself. My sources say this may happen sooner than you think.

The fork internals, yes. What I'm looking for, ultimately, are the fork cap with rebound adjuster fittings, and fork lower with compression adjuster fittings. Everything inside the fork leg can go in recycling.

Personally, I care F-all about 'active' suspension.I might halfway be interested in the USD forks, but they'd still have OEM internals...

oh, Yamaha has done a stellar job on the 13's suspension setup. Soaks up the bumps and doesn't beat you to death so it still handles nicely in the turns. Their is near 0 stiction from the front forks. Can't say how it behaves at 9 or 10/10ths. But at any sane street pace, VVG!

And see, here I am... Because a few days a year, I not only exceed sane street pace, I find myself playing rabbit for violator contact drills with motor cops, intentionally taking bad lines and doing other stupid shit- hoping they react in time, and hoping I can react in time if they don't. Most of the time I'm pretty happy with the stock suspension (for now), but on the track, I miss the well fettled boingers from my '04.

That and I'm pissed that I let a guy on a C14 get away from me this year.

There really isn't any reason to replace the GEN3 left fork with a GEN2 fork unless you are also going to change the internals on both forks and that should work without any other modifications.

Bingo! See, I have a line on a set of recently rebuilt Gen II GP Suspension internals from someone de-farkling in preparation for sale... If I can score those, it's cheaper than paying GP Suspension for a new setup.

Newer high-end shocks have high speed and low speed damping adjustments; My impression of the OEM suspension is that when it's pressed hard, the response is "late"- it's still trying to react to the last input when I'm halfway into the next one. I haven't been able to adjust it out.

Perhaps, ultimately, the solution is to just pony up for new, but see, there's a KLR in my garage- that should be enough explanation right there.

 

[AKjitsu]

2006 forks went on my Gen III just fine. KFG should have Gen III fork upgrades available any day now. I let them use my Gen III forks as test mules.

 

[FJRMGM]

2006 forks went on my Gen III just fine. KFG should have Gen III fork upgrades available any day now. I let them use my Gen III forks as test mules.

curious - why did you put 06 forks on your Gen III ?

 

[Fred W]

I would guess that he did that because the '06 fork is a known quantity. It is probably a set of forks that has already been fully worked over and optimized for his riding weight and style. And the '06 forks are adjustable for preload, compression damping and rebound damping on both sides. Not sure that the '13's are such a big step up.

 

[08FJR4ME]

Fred you let me down.

The real answer is because Gen I's are better than Gen II's but Gen II's are even bedda than the Gen III's.

Dave

 

[20valves]

...I'd swear that the Gen3 forks are of a smaller diameter than my Gen1 forks...

No, it's the booze.

 

[MCRIDER007]

I would guess that he did that because the '06 fork is a known quantity. It is probably a set of forks that has already been fully worked over and optimized for his riding weight and style. And the '06 forks are adjustable for preload, compression damping and rebound damping on both sides. Not sure that the '13's are such a big step up.

I would guess that he did it because the 13 forks are a big step down and he wanted upgraded forks ASAP rather than waiting for months for some suspension shop to figure out how the upgrade the 13 forks. I don't know any other reason someone would buy GEN2 forks off the internet and have them shipped directly to Traxxion to be rebuilt (didn't matter which GEN2 forks were used since Traxxion changes all the internals). It was a win-win for everyone because he got upgraded forks ASAP and GP Suspension got a set of 13 forks to work with.

The big question is what is the upgrade to the 13 forks to make them adjustable on both sides? Rebound on one side and compression on the other.....or re-machining the left side so the old fork kits will work? I have a set of AK-20s (previously installed in a GEN2) waiting to be installed in something. Traxxion said they could be transferred to a GEN3 and the cost would be "reasonable". I am guessing they would convert them to the compression and rebound damping on separate forks similar to what they do on the C-14s.

 

[20valves]

I would guess that he did it because the 13 forks are a big step down

Not true. Gen III forks are better sorted than my stock '06 Gen II forks were, as is the shock.

 

[Fred W]

I would guess that he did it because the 13 forks are a big step down

Not true. Gen III forks are better sorted than my stock '06 Gen II forks were, as is the shock.

In what regard are the new forks and shock better? Stiffer springs, I hear, but what is better sorted?

 

[MCRIDER007]

I would guess that he did it because the 13 forks are a big step down

Not true. Gen III forks are better sorted than my stock '06 Gen II forks were, as is the shock.

I'm not sure what "better sorted" means but if you want to upgrade the GEN3 forks is going to be more difficult and expensive than the GEN2 forks. The GEN3 forks also appear to be made of lower grade components. The GEN3 fork cartridge and springs at Yamahapartshouse.com list for $133.22 and $20.40, those same parts cost $240.89 and $26.64 for a 2012 model. I don't know why the cartridge cost dropped so much but when Yamaha says lighter damping parts the only thing I can think of that is lighter and less expensive than aluminum is plastic....which is being used in the damping pistons in the big piston forks.

 

[Old Guy]

Something I've noticed, and it may just be a visual thing, but I'd swear that the Gen3 forks are of a smaller diameter than my Gen1 forks. I'll get my thumb out tonight and measure.
oh, Yamaha has done a stellar job on the 13's suspension setup. Soaks up the bumps and doesn't beat you to death so it still handles nicely in the turns. Their is near 0 stiction from the front forks. Can't say how it behaves at 9 or 10/10ths. But at any sane street pace, VVG!

From my GenIII service manual, the fork "inner tube outer diameter -- 48mm."

Maybe someone could check the service manual for a GenII