fork preload

[Erci]

ok its kinda hard to measure with the clip on on it, but its rite at 1 1/4'', the clip ons are 1 1/2''.

That's gonna make for some very twitchy handling. Having said that, it *should* still be acceptable. Stock FZ6 rake is 25 degrees; sport bikes typically have 23-ish. Sliding the legs up 1" should equate to roughly 1 degree reduction, so you're now somewhere over 23. In other words very close to what a full on sport bike feels like.
Very twitchy and less stable, but turn initiation should feel quicker.

 

[FinalImpact]

Eric, if you notice where mine lands when all is said and done. 31 mm (sag) + 8 mm = 39 mm 1.5" and that is my comfy spot (FZ1 bars).

Now take mine when stock and it settles 1.7" just from me sitting on it (44mm), add another 1.5"!!!? I'd think that'd make the into the TWITCHMASTER 10,000! :BLAA: Not sure I'd like that too much and I had the rear sag at 29mm (#5).

Reap, care to do a test and move the clips below the triple? Just for a test run??

 

[ReapeR]

I was guna buy the woodcraft clip ons that I could put under it but I didn't cuz these were cheaper, and they wont fit under the clamp,

 

[ReapeR]

my bad, they weren't woodcraft, it was these.

 

[Erci]

So perhaps extra preload is the way to go to improve the handling? Easy enough to cut PVC spacers and drop them in, right?

 

[FinalImpact]

Reaper - curious, how do measure the clip-ons for proper for aft placement? My thinking was, if it was off a tad that may give you that 'listing feeling" as ones body may actually be steering the bike.. .. ..

I suppose you could set some bars in the triple clamp and look down on it??

 

[Hellgate]

You can't adjust the preload on stock FZ6 forks.

Complete guess here, however, from what you are saying you took one of the fork's to get the seal replaced in which case the dealer more than likely replaced the fork oil while they were at it. Which means that you have new oil in one fork and old oil on the other fork, possibly with a different weight as well, maybe even a lower/higher amount than the other fork. That would explain the what you are experiencing. If I were you I would replace the fork oil on both to start off with.

Oh yes you can! Go to the hardware store. Buy the appropriately sized washer. Remove fork cap. Place washer on top of spring. Place fork cap in socket. Press down and turn.

One standard washer is equal to "about" one clip on a Yamaha preload adjustable fork cap.

The more washers, the more preload.

 

[Hellgate]

Raising the forks up through the clamps can cause instability, normally in the form of headshake under acceleration. Absolutely make sure that the forks are an equal amount through the clamps, otherwise the bike could well feel unstable generally.

Back to oil level, an unequal level can cause instability, unlikely to be evident at high speeds though, more so at lower speeds and whilst braking. However, considering only one fork has been serviced, are we even sure that the same oil was used as is currently within the unserviced fork? Even if the same weight was used this is still likely to cause issues, as not all manufacturers weights tally. Again it's well worth replacing the oil in both forks and ensuring that the heights are correct.



I agree partly with this, however the terms you've used are slightly confusing your explanation.

If the forks are pushed up through the clamps (more fork showing above the top clamp) the rake changes through the lowering of the front of the bike relative to the rear. This affects the mechanical trail, the distance at which the tyre contact patch trails the steering axis' intersection with the road surface. The larger the mechanical trail, the higher the self centring torque developed by the resistance of the tyre contact patch to rolling along the road surface. Lowering the front end effectively reduces the trail number, hence self centring torque, with raising the front increasing the number, and therefore the self centring torque.

Increasing ride height in the front to compensate for the fork position is not really advisable, ride height (sag) should be set to the correct value (35-40mm for street) to allow the suspension to work within its most compliant mid stroke. This also allows geometry to be best maintained when the fork is in operation.

Lowering the rear can be done to correct the mechanical trail, however this is not really recommended as, as you've mentioned, travel will be lost, plus the bikes 'flick-ability' will be reduced. Again the sag should be set to allow the suspension to work within its mid stroke (30-35mm for the rear on the street).


Yamahaboyz

The R6 fork on my FZ6 is about 10mm shorter than stock. The R1 fork on my FZ1 is about 10mm shorter than stock. The fork on my R6 is moved up and down depending on the track. The fork on my XV920R is about 10 to 12mm lower.

So no, stability is not an issue in any of the above cases.

 

[iSteve]

The R6 fork on my FZ6 is about 10mm shorter than stock. The R1 fork on my FZ1 is about 10mm shorter than stock. The fork on my R6 is moved up and down depending on the track. The fork on my XV920R is about 10 to 12mm lower.

So no, stability is not an issue in any of the above cases.

Of course moving a racing fork just 10mm will make just a slight difference. But in the op's case he dropped the front about 32mm.

 

[chemicalsmile]

ok its kinda hard to measure with the clip on on it, but its rite at 1 1/4'', the clip ons are 1 1/2''.

Yikes, I improperly torqued my triple clamp bolts once, lost one and the forks slid around that far up. Had to ride 15 miles or so to get to a hardware store and it was super twitchy but turn in was amazing haha.

 

[motojoe122]

I had a hard time finding spacer stock locally and didnt want to use PVC pipe when I had my racetech springs, I ended up ordering spacer stock from racetech directly. I think it about $20 or so.

 

[ReapeR]

ok umm, think it was just the front tire, i thought i checked it but guess not, and its been sittin all winter, had 15 psi spose to be 36. rides alot better now on a wore out tire.

 

[motojoe122]

ok umm, think it was just the front tire, i thought i checked it but guess not, and its been sittin all winter, had 15 psi spose to be 36. rides alot better now on a wore out tire.

You're kidding, right?:BLAA:
Sometimes the simple things are overlooked

 

[ReapeR]

I coulda swore I checked it the other week, but I took it to a shop close by and told em the prob and they asked if the front end was heavy I said yea they said it the tire low I said no they went out an checked it and had 15 psi, I felt like a idiot, got back to my shop and pumped it up went back out and handled a lot better, now just need a new tire where it rode on the right side.