FJ Forks or YZF600 Forks

[petetb154]

Ok, first a confession, I have moditus.

Now the question. If you had an '87 and were upgrading the front wheel, would you prefer a late model FJ wheel/fork or a 98 YZF600 wheel/fork.
I happen to have a YZF wheel with rotors in my possession. I should receive a 90 FJ wheel without rotors in a few days. I cant decide which way to go.
I'm going to paint the wheel & fender either way, and I am going to use blue-spot R1 calipers either way. I'll sell the wheel I don't use.

FJ Front end:
1989 Forks   $316 (having to pay to have them shipped from UK)
RPM Cartridge inserts   $214
New Front Rotors   $179
Total   $709

Pros:
Easier mod
Standard parts (will make it easier to remember what I did in 20 years)
$40 cheaper
FJ original looking front fender

Cons:
damper rod fork
3.0" front wheel

YZF Front end
88 FZR steering Stem & triple tree   $52
98 YZF600 Frorks   $150
98 YZF600 Fender   $50
98 YZF Axle, spacer & speedo    $35
Springs - RT FRK SPR 34.7x340mm 1.0kg   $114
RT Gold Vlave - FMGV S2040B     $180
RT RB Valve - FRGV S01     $170
Total   $751

Pros:
Cool looking front fender
3.5" wheel
great cartridge forks

Cons:
Slightly Harder Mod, will also need more misc fasteners etc
I may never remember what I did in future (i.e. Imagine trying to remember what fork seals to order in the year 2035)
I hear these forks are a little shorter, and i might need to screw with that.

[FJmonkey]

FJ Front end:
1989 Forks   $316 (having to pay to have them shipped from UK)
RPM Cartridge inserts   $214
New Front Rotors   $179
Total   $709

Pros:
Easier mod
Standard parts (will make it easier to remember what I did in 20 years)
$40 cheaper
FJ original looking front fender
Awesome suspension with the RPM valves

Cons:
damper rod fork No longer damper rod with RPM valves, they become RPM cartrige valve forks
3.0" front wheel (or use the FZR1000 88/89 wheel 17" x 3.5", bolt on upgrade)

YZF Front end
88 FZR steering Stem & triple tree   $52
98 YZF600 Frorks   $150
98 YZF600 Fender   $50
98 YZF Axle, spacer & speedo    $35
Springs - RT FRK SPR 34.7x340mm 1.0kg   $114
RT Gold Vlave - FMGV S2040B     $180
RT RB Valve - FRGV S01     $170
Total   $751

Pros:
Cool looking front fender
3.5" wheel
great Good cartridge forks

Cons:
Slightly Harder Mod, will also need more misc fasteners etc
I may never remember what I did in future (i.e. Imagine trying to remember what fork seals to order in the year 2035)
I hear these forks are a little shorter, and i might need to screw with that.
Cartrige valves are not bi-directional like the RPM valves.

[simi_ed]

Mark, you glossed over the cost of the FRZ wheel, mine ran about $125.  As far as rating the Racetech-YZF forks as "good" I'd have to disagree.  I'd also call installing the RaceTech parts a PITA.  But IMHO, the results have been excellent. 
Perhaps we can swap rides one day & then compare notes on the front end operation of RPM vs RaceTech.

[Mike Ramos]

Right on target Mr. Monkey,

I would like to add the Fork Valves from RPM will out perform the cartridge forks, certainly units of that period.

There are several videos of the RPM forks in action somewhere on this Forum, one being A Short Ride at the Colorado Rally.

Also, improved tire wear should be taken into account when then cost are figured, a fact that has been proven through several sets of tires & many miles.

In addition, the fork oil remains clean, indicating minimal wear on the internals.

Finally, Mr. C. maintains that the correct sized front axle will be used....

Ride safe & keep smiling,

Midget.

[yamaha fj rider]

Having done the lesser expensive route, I think the fork swap is the way to go. Others may disagree JMHO. Plus you can still upgrade the new forks making them even better. Hope this helps.

Kurt

[racerrad8]

Pete,

You only need the late model lower sliders of the front forks, not the complete fork.

I see there an not any listed on eBay right now, but they will come around and you should be able to beat the UK set with shipping.

Randy - RPM

[rktmanfj]

I swapped my stock FJ fork for the YZF600 unit several years (thanks again to the fan for doing the original build) and recently had them refreshed by 35 motorsports.  Even with Traxxion 1.1 springs, Superbrace and the full Race Tech treatment (and the refresh, as well) I'm in them for a good deal less than your estimate.  I was patient and scored (on eBay) a low miles fork, complete with everything from the bar ends down (switchgear, grips, horn, complete front brake system) for $150.  I'll admit that it took several weeks of looking, though.

It's a great fork... well tuned, compliant, and well worth what I have in it.  A definite upgrade over the stock FJ fork.

I've not yet had the pleasure of getting to compare it to the new RPM valves, but by all accounts they are every bit as good, and I'm strongly considering using them in my '90 project FJ if I can adapt the FJ fork to the 17mm YZF axle.  If I can do that, I can run the YZF wheels on both FJs (I have 3 sets).

Bottom line, I don't think you'd be disappointed in either one.

[petetb154]

Having done the lesser expensive route, I think the fork swap is the way to go. Others may disagree JMHO. Plus you can still upgrade the new forks making them even better. Hope this helps.

Kurt

Do you mean that you'd suggest the YZF fork mod?

[petetb154]

FJ Front end:
1989 Forks   $316 (having to pay to have them shipped from UK)
RPM Cartridge inserts   $214
New Front Rotors   $179
Total   $709

Just realized that I can use the rotors off the YZF wheel on the FJ wheel, saving me $179.
Maybe I'll go with the FJ upgrade, and wait for cheaper forks than the ones from the UK. Should cut the cost considerably.
If nothing else, fewer big parts showing up at the front door will make the UPS man happier and my wife less suspicious of what I am up to!

[racerrad8]

I would like to add the Fork Valves from RPM will out perform the cartridge forks, certainly units of that period.

Midget.

Let me expand on this statement. The RPM fork valve is a valve that compensates for both high & low speed travel via the patented technology. The usd cartridge forks can be tuned for a specific area, but cannot compensate for both.

The cartridge fork is great for racing applications where you have a smooth racing surface and they can be properly set up. But if you take that set up on the road rough roadways the bike will ride terribly. So, the cartridge forks for the street bike as tuned to a compromised setting for the best performance possible but still allow a decent ride upon the highway.

The RPM fork valve does not compromise one over the other, because it has dual valves to handle either smooth (slow travel) or rough (fast travel) surfaces.

So, yes usd cartridge forks do offer better tuning over stock FJ damper rod fork, but just like the Penske, Hagon or any other aftermarket rear shock available for the FJ, there is a compromise in tuning to offer the best performance over the range required for street bikes.

The RPM fork valves & rear shock do not not have to compromise as they incorporate patented technology that allow the suspension to be tuned based on the FJ specifically for proper operation in both slow & fast suspension travel which results in superior performance.

Randy - RPM

[JCainFJ]

 I've done many FJ fork swaps using YZF600 forks and it works very well. I have not tried the RPM stuff so I don't know about it. If its patented technology, someone needs to explain it.  Same thing with the shock. Why is it better then the Penske / Ohlins / etc. I'll reserve my judgement untill I test ride my bike and an RPM prepped FJ same day, same roads. Caveat emptor!

[yamaha fj rider]

Having done the lesser expensive route, I think the fork swap is the way to go. Others may disagree JMHO. Plus you can still upgrade the new forks making them even better. Hope this helps.

Kurt

Do you mean that you'd suggest the YZF fork mod?

Yes.

Kurt

[racerrad8]

If its patented technology, someone needs to explain it.

It is all explained below;

RPM fork valves explained
RPM fork valves
Let the fun begin...RPM Rear Shock


If you have anymore questions please let me know, I will be more than happy to answer them.

Randy - RPM

[Pat Conlon]

Don't forget the stiffer front axle (17mm vs 15mm) on the YZF mod.
BTW, I don't see anything in your YZF budget for a handlebar.

A couple of years ago this was a no brainer, YZF all the way....but along comes Randy and introduces the IAT valves and the whole game changes.

[rktmanfj]

Don't forget the stiffer front axle (17mm vs 15mm) on the YZF mod.
BTW, I don't see anything in your YZF budget for a handlebar.

A couple of years ago this was a no brainer, YZF all the way....but along comes Randy and introduces the IAT valves and the whole game changes.

FWIW Pat, I made up a set of the Jon Cain style adapter plates and used the FJ bars with the YZF forks.

Since I got to drill my own index hole for them, I was able to spay the bars out a few degrees, doing away with the 'numb hands' issue the stock angle always caused.