question about fork bushes

[sheltiedave]

Half way doing the race tech mods to my FZ6 suspension ( damper is spinning around refusing to let go :shakehead , I know the oil seal under the dust cover will need replacing . But will the top and bottom bushes on the lower fork tubes need replacing too ?

Also is there part number for them ?

Cheers , Dave

 

[FinalImpact]

Re: question about fork bushings

Depends how many miles and how its used. Rough roads can induce more wear. Try NOT to spin the tube, its not helping your cause. Also if you do replace them, use the proper bushing driver or you might be wasting your time.

You need an impact gun and a wooden stick. Invert the fork, shove a wood handle from something into the stanchion tube and then push down on the body AND hit the trigger of the impact gun a couple of times until the bolt comes out. Usually its the Loctite holding it together.

Good luck!

So, are you installing springs and emulators??

 

[sheltiedave]

There is about 26,000 miles on the bike , I was just thinking does the bushes get damaged when taking the forks apart or just best to replace while this deep into the forks .

Will give the impact gun and wooden stick method a try :thumbup:

Installing , well trying to install , springs and emulators .

 

[FinalImpact]

There is about 26,000 miles on the bike , I was just thinking does the bushes get damaged when taking the forks apart or just best to replace while this deep into the forks .

Will give the impact gun and wooden stick method a try :thumbup:

Installing , well trying to install , springs and emulators .

Typically not. The only additional wear induced would be if the stanchion spins in the body which is not likely.

Because us DIY lack the exact tool for the job to install them (Press and bushing driver), I might opt to leave them unless they are loose when fully compressed (least worn area of stanchion). If they are only loose in the area of ride height, now you need an accurate way to measure the stanchion tube for wear. Make sense? i.e. - if the stanchion is only loose at normal ride height, than bushing replacement likely will not correct it as its not the bushing that is worn.

 

[sheltiedave]

I quickly put the fork back together and with a borrowed impact gun and spun that bolt out in seconds :thumbup: An impact gun has gone straight to the top of my " stuff I need " list.

Right hand fork is done, emulators , springs , cut down spacers but now minus oil at the moment , it's been a steep steep learning curve but I know what to do for the left fork so it shouldn't take all day like the right fork did

Just a question about the sag , I think I understand how to measure for it and come up with an number , but is there a standard number/s I'm looking to reach ?





Oh yeah , 26,000 mile old fork oil isn't very nice !!

 

[FinalImpact]

I quickly put the fork back together and with a borrowed impact gun and spun that bolt out in seconds :thumbup: An impact gun has gone straight to the top of my " stuff I need " list.

Right hand fork is done, emulators , springs , cut down spacers but now minus oil at the moment , it's been a steep steep learning curve but I know what to do for the left fork so it shouldn't take all day like the right fork did

Just a question about the sag , I think I understand how to measure for it and come up with an number , but is there a standard number/s I'm looking to reach ?





Oh yeah , 26,000 mile old fork oil isn't very nice !!

Good Stuff ^^ lol

Depends - I ride mainly canyon / mountain roads and little freeway use.
Rider Front 33 / Rear 29 mm < R6 forks on OEM R6 springs which are getting weak.
Bike Front 16/ rear 10 mm <OEM rear spring on R1 shock

Ideal:
Bike sag ~ 10 - 13mm
Rider sag ~ 30 - 35 mm and you should be good.

One article says Street bikes need 10 - 15 mm of static sag. i.e bike only.
>10mm = need higher rate springs
<10mm = need lower rate springs

 

[sheltiedave]

Good Stuff ^^ lol

Depends - I ride mainly canyon / mountain roads and little freeway use.
Rider Front 33 / Rear 29 mm < R6 forks on OEM R6 springs which are getting weak.
Bike Front 16/ rear 10 mm <OEM rear spring on R1 shock

Ideal:
Bike sag ~ 10 - 13mm
Rider sag ~ 30 - 35 mm and you should be good.

One article says Street bikes need 10 - 15 mm of static sag. i.e bike only.
>10mm = need higher rate springs
<10mm = need lower rate springs

i said in my previous post I understood how to work out the sag , it turns out I think I don't

I'm assuming when taking the measurements the bike is in a full ready condition ready to run ?

Quotes from the instruction which I don't think I'm following correctly ,

Step 1: Extend the fork completely and measure from the wiper (the dust seal atop the slider) to the bottom of the triple clamp (or lower fork casting on inverted forks; Figure 2). This measurement is L1.

Is the bike meant to be sitting on the centre stand with the front wheel off the ground for this measurement ?

Step 2: Take the bike off the sidestand, and put the rider on board in riding position. Get and assistant to balance the bike from the rear, then push down on the front end and let it extend very slowly. Where it stops, measure the distance between the wiper and the bottom of the triple clamp again. Do not bounce. This measurement is L2.

Pretty simple this one

Step 3: Lift up on the front end and let it drop very slowly. Where it stops, measure again. Don't bounce. This measurement is L3. Once again, L2 and L3 are different due to stiction or drag in the seals and bushings, which is particularly high for telescopic front ends.

I assuming once again this measurement is taking with out anyone on the bike and the bike sitting on its wheels ?

once L1 - [L2 + L3) / 2] is worked out is that rider sag?

and the difference between L2 and L3 is static/bike sag ?

 

[greg]

i didn't need an impact gun to get the bolt out, just press the wooden broom handle in as hard as you can. whilst undoing the bolt

 

[sheltiedave]

I'm getting for L1 132mm
L2 77mm
L3 100mm

adding up to 43 mm , thats with all the washers fitted in the forks , guessing I made the spacers too short .

 

[Hellgate]

If you're in there you may as well replace them. Fork bushings are cheap and easy to replace, all of $6.00 each. 4TX-23135-B0-00 METAL, SLIDE 2, 4TX-23125-B0-00 METAL, SLIDE 1

Yamaha Motorcycle Parts 2009 FZ6 - FZS6YCB FRONT FORK Diagram

 

[Hellgate]

Suspension set up, read this: 403 Forbidden < it works, really...

 

[FinalImpact]

BIKE SAG:
L1) Forks fully extended (wheel off ground), measure from seal to triple.
L2) Bike on ground, 1/2 tank of fuel, bounce nose allow to settle. Measure from seal to triple.
Repeat 3X and average

L1-L2 = Bike sag or static sag

If SOLO, just you: You can use a zip tie around the stanchion and do this solo. Just bounce the bike let it settle on its own weight (2 tires), push the zip tie to the seal and carefully lift the nose without pressing down. The distance the zip tie is from the seal is the bikes sag when the forks are fully extended.


RIDER SAG SOLO MEASUREMENT:
With a wall or post next to you, you can board the bike, get into riding position, use something long and push the zip tie down onto the seal.
- Now carefully remove yourself from the bike WITHOUT depressing nose.
- Measure from the zip tie to the seal with the Forks FULLY EXTENDED. That gets your rider sag.
- Repeat 3X compute average

RIDER SAG 3 People: The best way is with 3 people.

• Rider on bike.
• Holder to hold bike.
• Someone to measure.

OR - with two people and a post or wall.
Rider in position next to wall to brace bike upright.
One person to measure sag (triple to seal) for L2 distance.

L1 - L2 = Rider SAG Repeat 3 times and average it.

PS - I think the process you're trying to implement is to correct for seal stiction. You can get all tricky and attempt to take out stiction which amounts to attempting to get the average (where does the suspension settle) by measuring from rebound stop and compression stop and compute the average for L2 like so.....

Best method but takes at least two people:
* Push down on bars, let bike come up with you on it. Record #
* PULL UP on bars, let bike settle with you on it. Record #
X3 to verify numbers.
Average out the sets, subtract from Original L1

 

[FinalImpact]

Suspension set up, read this: Sportrider - Suspension Setup Guide < it works, really...

More from other places....
Visit this!

Tire wear patterns.... Race Track Motorcycle Tyre Wear Guide - Types and Causes
Bike setup vid w/ Dave Moss.... https://www.youtube.com/watch?v=Ikjw4IheeF4
Bike Setup Tech article..... Motorcycle Suspension Set-up

We have a nice collection!

PS - if you get creative with a some firm wire, you can measure real info by strapping a metric ruler to the fork bodies and measuring with a pointer. One can also do the rear by yourself too!!! You just have to get creative and use a camera to capture ride height! Ask me how I know! :thumbup:

 

[sheltiedave]

Thanks for the help folks :thumbup: More of an understanding now and good idea with the cable ties for getting measurements .

Turns out I have made a mistake when cutting the spacer tube , I just got the zero preload measurement and then cut the tube without adding preload , so it's about 20mm short !! So looking out for more tubing for spacers , Ebay .

 

[FinalImpact]

Thanks for the help folks :thumbup: More of an understanding now and good idea with the cable ties for getting measurements .

Turns out I have made a mistake when cutting the spacer tube , I just got the zero preload measurement and then cut the tube without adding preload , so it's about 20mm short !! So looking out for more tubing for spacers , Ebay .

Bummer - TIG them back together and try again! :thumbup:
PS - Some use schedule 80 PVC pipe for tuning. When done, cut the metal to the desired length.

At 26°F outside today, I stayed inside and did some of my own...
Inside the R6 Spork!
Notice the outer bushing came out when I pulled the inner stanchion free. Its on the stanchion tube.

 

[sheltiedave]

It's a bit annoying with the spacer but at least they're easy to replace and I know what to do now . Plus trying the PVC pipe is a good idea :thumbup:

Also going for braided lines on the bike and noticed the seals in the front wheel are on their way out , so it's going to be a little while before the bike is back on the road . Front tyre is also looking like it's on the legal limit and I'm sure there will be something else !!

In your picture , above the outer bushing is a big washer . Well I was just finishing off one fork , pouring in the last of the oil when I looked down at the work bench and there was the washer :shakehead: Had to pull it all apart and start again !!

 

[FinalImpact]

It's a bit annoying with the spacer but at least they're easy to replace and I know what to do now . Plus trying the PVC pipe is a good idea :thumbup:

Also going for braided lines on the bike and noticed the seals in the front wheel are on their way out , so it's going to be a little while before the bike is back on the road . Front tyre is also looking like it's on the legal limit and I'm sure there will be something else !!

In your picture , above the outer bushing is a big washer . Well I was just finishing off one fork , pouring in the last of the oil when I looked down at the work bench and there was the washer :shakehead: Had to pull it all apart and start again !!

You know the front seals are just dust seals right?
As long as they keep dirt and water out, seeping grease is normal.

In this shot, I just re-greased before installing wheel (new tires)....

Do you suspect any kind of bearing failure or fault? Turn by hand with finger tips. Should be smooth and firm. Not rough....

 

[sheltiedave]

There's no lip left on the seals and it looks like they have been breaking up , but will need to check the bearings too .

 

[FinalImpact]

Did you get the preload issue taken care of?

And what did you bike and rider sag come out to?

 

[sheltiedave]

No, not yet. Haven't been able to get more tubes yet as most places are still closed but should be back to normal tomorrow and hopefully the bits needed.