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Front fork "sag" ?

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I had my suspension done by Factory Connection 6 mo ago.

I took my forks to local shop for new seals/fluid change.

I got them back, bolted them up.

Here is my question. Should my forks "sag" about 1-3/4" just from the weight of the bike? If I pull up on the bars they will stay at full extension until I push down, then they stay "sacked out" a couple inches.

Thanks for your help.

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Yeah, but how much is too much?

I remember seeing a figure a while back, I thought the sag was supposed to be around 1".

I'll have to measure mine tonight if I remember.

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"Fork sag", just like shock sag is based on spring rate, rider weight and rider "intended use"... which will have a bearing on spring rate.

The only difference is adjusting fork sag is that it's not as quick and easy as shock sag... unless you happen to have a fork with preload adjusters, and those tend to have a pretty limited range.

Another thing to consider is fork "stiction"... sliding/sticking friction.

Forks have far more sliding drag and friction than a shock and even a link assembly (assuming it's clean and well lubricated) so a sag measurement is harder to do... at least repeatably and accurately

Want to make your forks operate smoother... with way less stiction? Easy stuff.

1. Pop your dust seals down, clean what ever crap is stuck in your fork oil seals with a business card or piece of 35mm film... or what ever blows your skirt up.

2. Next, clean your dust seals and fork legs inside and out... peel the springs off so they aren't so tight on the fork tubes if you have to. Use some sort of plastic polish or rubber cleaner... or failing that, even WD-40. Anything that will clean and doesn't hurt rubber.

3. Next... in the cavity of the dust seal, pack it with a light-body waterproof grease. If you have real live suspension grease, perfect! If not, BelRay, Motorex and Maxima come to mind as makers of good light general purpose grease.

4. Next, reassemble your dust boots and re-install them into the fork tubes. Work your forks up and down several times and wipe the excess grease off the fork legs. You may have to do this a few times before it stops leaving a little grease on the tubes. Wipe the tubes down again with a light cleaner/lubricant.

What have you accomplished? A few things actually... good things at that.

1. You've created a "grease trap" to collect debris that get past your dust boots... before they get to your fork oil seals. This will reduce oil seal failures and extend the life of your seals.

2. You've lubricated and reduced the sliding friction and drag in an area of your fork that is commonly overlooked by everyone but professional race mechanics. Those super slick fork leg coatings the pros use ain't cheap either.

3. You've given your motorcycle some well deserved, extra special love. It will thank you later.

If you stroked your forks up and down prior to doing this, then after... you will immediately notice that your fork action is quicker and more responsive. Almost like you backed way off on the dampers, or put in stiffer springs.

When you check fork sag (if you ever do)... it will also be far more "repeatable" than with dry, dragging dust seals.

Thats it,

C

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I asked the question in the suspension forum a couple of months ago about putting grease in the cavity between the seals and was told by a couple different people that the grease will actualy attract more dirt and make your fork seals more likely to leak. Is this true or myth?

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you should always measure your ft and rear race sag and record those numbers , -----cold --and hot at the track-------i like to see 40 to 65mm of ft sag for starters.

you can quickly change ft fork sag by bleeding the fork at the top of its travell------( which is where the book tell you to bleed it )----or you can pull the ft of the bike down and bleed the fork there and then let it actually have a vacumm in the fork ( which is where most guys in the know will have their bikes set up at )--

and this will change your ride height at the stanchion tubes, ---and you can raise and lower your bike slider tubes in the clamps and also change the ft ride hight .

so actually the ft is easy to alter.

and of course you should always suck your bike down in ft and bleed it there and then let it up to have a big pull of vacuum in the tubes when you are letting it sit overnight or for afew days --( i have a vacuum in my tubes all the time , --at the track and at the shop )---so you will not let oil weep into the seals and start them leaking -------and of course check for nicks daily and remove any with a file and fine sand paper.

once you finnally get your chassis set to where you become one with the bike ------it is so nice to be able to just move the ft 1 mm or so and really know what it will do on a givin track !!

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I asked the question in the suspension forum a couple of months ago about putting grease in the cavity between the seals and was told by a couple different people that the grease will actualy attract more dirt and make your fork seals more likely to leak. Is this true or myth?

it is better to keep your stanchions really polished and free from water spots and just have alittle seal grease in the seal when assembling the fork ------

and right before you load to go ride i like to take mobil one atf and polish the stanchions with it ------this really get out the stiction and will last one ride day ----

once you get into the habbit of measuring your bike all the time , ---recording the numbers , and keeping the stanchion's polished with atf -----keeping a vacuum pulled on the forks --checking and re-setting tire pressures all throught the day ---it just becomes habbit and it really lets you start to learn what your chassis is doing and how to make you bike handle the way you need it to . 🙂

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