Gt fork on fjo9 ?

[Tripletrouble]

I've just received s/h left fork leg complete to replace scratched gold tube on my existing 17 model. It has a comp screw on cap, so thinking it might be off a gt model. Axle orientation is correct. Will this be a direct swap over, as it measures as my existing ? 

[betoney]

1 minute ago, Tripletrouble said:

I've just received s/h left fork leg complete to replace scratched gold tube on my existing 17 model. It has a comp screw on cap, so thinking it might be off a gt model. Axle orientation is correct. Will this be a direct swap over, as it measures as my existing ? 

It should be a direct fit.

[BBB]

13 minutes ago, betoney said:

It should be a direct fit.

Are they the same in terms of fork internals as well as external dimensions? Genuinely curious.

[betoney]

5 minutes ago, BBB said:

Are they the same in terms of fork internals as well as external dimensions? Genuinely curious.

I believe that the only change Yamaha made was to separate rebound and compression adjustment between the left and right fork leg.  The fork o.d. and length should be identical.

[Tripletrouble]

Thanks for confirming Betony, Just wanted to make sure I wasn't missing anything like my normal bright ideas.  Bbb..The left Tracer leg just has a spring and oil. On the left GT leg they have now added compression adjustment. The right side both have rebound.  They measure identically, so my thought was to buy a s/h Gt. leg to get a little more adjustment without spending a crap load on andreani cartridges. (Way better option if....you have the funds) but had to make a sudden decision without fully researching. Not sure it will make a massive difference. Actually, since I can't ride at moment, it won't make ant difference ! 

Edited April 2, 2020 by Tripletrouble

[betoney]

2 hours ago, Tripletrouble said:

Thanks for confirming Betony, Just wanted to make sure I wasn't missing anything like my normal bright ideas.  Bbb..The left Tracer leg just has a spring and oil. On the left GT leg they have now added compression adjustment. The right side both have rebound.  They measure identically, so my thought was to buy a s/h Gt. leg to get a little more adjustment without spending a crap load on andreani cartridges. (Way better option if....you have the funds) but had to make a sudden decision without fully researching. Not sure it will make a massive difference. Actually, since I can't ride at moment, it won't make ant difference ! 

And while you are at it, get the correct springs for your weight.  It makes a huge difference in the feel of the ride.

[Tripletrouble]

Thanks Betony. Blew my funds a while back on a nitron shock, as it's the crap rear shock that was causing the biggest problems, but springs are on the list when the lockdown is over, as can't test or ride at moment.  The fronts not ideal, but after messing with different weights, I put slightly heavier oil in, 22cst, up from 15.8 ( most go lighter, or think they do) and wound out rebound more, so livable with for the time being. What weight are you, and what rate spring did you put in ? How is it on small frequent bumps which are what passes for U.K. Roads at the moment ? 

[betoney]

8 minutes ago, Tripletrouble said:

The fronts not ideal, but after messing with different weights, I put slightly heavier oil in, 22cst, up from 15.8 ( most go lighter, or think they do) and wound out rebound more, so livable with for the time being. What weight are you, and what rate spring did you put in ? How is it on small frequent bumps which are what passes for U.K. Roads at the moment ? 

I weigh 230# and use either .95 or 1.0kg/mm fork springs (can't remember, its been 3 years) but I am using modified fork cartridges.  Both legs have custom built rebound and compression circuits and adjustability. 

I have mine setup just soft enough to be comfortable yet taught enough to maintain composure and hold a line in the fast corners.  Maybe somewhere between an FJR and an R1 if that makes sense.

[Tripletrouble]

How much of the improved ride was because of the cartridge mod, vs the springs ? 

[betoney]

4 minutes ago, Tripletrouble said:

How much of the improved ride was because of the cartridge mod, vs the springs ? 

On this bike I upgraded everything at once, the springs came with the cartridges. 

On my previous FZ1 I did everything incrementally, I bought it with stock suspension and then upgraded the springs front and rear, then eventually upgraded to R1 components (popular mod on the Gen II FZ1) and inevitably upgraded the springs... Then... I bought a Penske shock and had the R1 forks professionally revalved.  Every step was a vast improvement, the heavier springs greatly help eliminate brake dive and shock squat.

After the final step, the bike was PHENOMENAL, there were times I would charge through a corner at +25mph over the speed limit giggling like a madman in my helmet.  Unfortunately, a few days after finally getting it perfected, I hit a deer and totaled the bike.  At least I was able to strip the bike and resell the parts before sending it to salvage.

 

[Tripletrouble]

I put in slightly heavier for oil, it made a difference in fork dive, but had to click rebound out to stop the small bump chattering. The nitron rear shock improved the bike big time, and has sorted out a lot of problems that I thought was the forks, as you've said, it squats under acceleration, then bounces up giving the front forks a lot of work to do. I'll get heavier springs down the line, though I think it's the damping that's the real culprit. Or just wheelie everywhere...

Edited April 3, 2020 by Tripletrouble

[BBB]

4 hours ago, Tripletrouble said:

...to stop the small bump chattering...

...then bounces up giving the front forks a lot of work to do...

..think it's the damping that's the real culprit...

It’s the damping for sure. 

I was sent this by Maxton, when I asked about possible fork upgrade solutions.

“The front forks on the MT-09 Tracer are upside down forks with preload adjustment in both legs but only rebound damping adjustment in one leg. The forks feel like ‘harsh pogosticks’. Over small bumps they can kick and make the front end a bit nervous at high speeds, but the biggest problem with these forks is the lack of rebound damping, this causes the front of the bike to spring back very quickly when you let go of the brake, making the bike difficult to get in to a corner and run wide out of corners. The springs in the forks are OK for the average rider weight.
The damping and springing have been split between the forks, the left leg has a spring inside but no damping and the right leg has a spring and damping inside. This means that the damping leg has to have twice as much rebound damping and compression damping to compensate for the other leg having no damping.
The damping leg can be revalved to try and prevent the forks springing back too quickly, but when you do this the ride becomes even harsher over small bumps. This means you can not revalve the damping successfully, so we replace the internal fork cartridges for our GP20 fork cartridges. The Maxton GP20 fork cartridges have rebound damping and compression damping in both legs.”

[Tripletrouble]

BBB. Well, that makes total sense. Harsh pogo sticks, what a great and accurate description ! Strange Yamaha don't use that in their brochure.😄I guess the heavier oil I put in has a similar effect to stop spring bouncing back, and found I could use the rebound adjustment screw to better effect. It's still odd that most recommendations have lighter oil, which to me made it worse ? I just messed about myself with the oil and heavier was better (for me) However, it seems a trade off.  fast riding = more stable vs slow riding feeling the bumps. Still, £12.00 on oil is better than £500.00 on cartridges, as I have another hobby called buying food. That's great info from Maxton, thanks for the reference.

[piotrek]

In my experience... I was able to achieve good compression and rebound damping performance with just the one OE leg re-valved, but I also managed a decent performance with OE valving prior to the upgrade, with the right-sized springs, and much thinner oil. I re-valved because the range of adjustment was very limited.

My selection of oil viscosity was more biased toward the compression damping performance (because it's fixed), and the rebound damping could then be tweaked because it's adjustable. Of course, you'll need to start with the right springs. YMMV.

[Tripletrouble]

On 4/2/2020 at 3:39 PM, betoney said:

It should be a direct fit.

I've just had a thought why this might not work. The right leg must have some compression damping, although not adjustable. The left doesn't have any damping at all, so the right must be valved to do the work of 2 legs ? If I fit the left gt leg, which has a damping rod, am I effectively adding more compression and possibly rebound ? I wonder if the right gt leg has different valving to compensate, maybe just rebound ?  Mmm. My reason for doing this mod, is so I can put light oil in left compression leg, and keep heavy in right rebound side. At the moment, with one leg for all the damping, it's a huge compromise of heavy oil for rebound, good, which then stiffens compression, bad. 

Edited April 4, 2020 by Tripletrouble