Anyone running ATF in their forks?

I have seen some posts of people running Synthetic Mobil ATF in their forks. How well does this work? I am getting ready to replace the seals in mine and I was thinking about trying it.

it works.....but so does fork oil. I use BelRay 7wt.

If I were to go with regular fork oil, what would you reccomend I put in. I weight 165lbs 5'10 and I mostly ride harescambles with the occasional motocross track?

I would use 7wt Belray and fill them 100mm from the top

Thank you, I will give it a try. :thumbsup:

Read this thread and the job will be easy and you will love the results.

Changing Fork Seals Thread

I'm personally sold on the Yamaha 01 oil. A little pricy but good stuff. Search here and you will find lots of threads on fork oil.

How much oil do I need to buy to do both forks? I am going to pick some up today after work.

I filled both sides of mine (46mm '03 450F) with 1 liter of Maxima 5wt (filled to 130mm) and had a very small amount left over. It wouldn't hurt to pick up an extra. The liter barely does it.

Sounds good. I will grab 2 then. Thanks for the input.

I would use 7wt Belray and fill them 100mm from the top

7wt at 100mm? Wow I bet you could jump off a building and not bottom.

actually they are plush.....Me likey!

Keep in mind that is 100mm for the top of the fork tube with the forks completely compressed.

Sorry to hijack the thread......

I'm a fat (little over 200lbs w/o gear) old guy (43) beginner, with a couple MX (actually AX) races in this year. I can only do a few of the very small jumps so I'm getting my butt kicked. Rather than go all out on the bigger jumps I've been just jumping a litte further each time. Well, that hurts and I notice my front end is bottoming out (not really hard though). I want to make sure if I miss the landing I've got something there to soak it up.

I'm on a stock 2001 426 (lightly used) with the compression clickers all the way in. Forks have never been serviced. Someone told me to order the stiffer springs (#42 I think) but after reading this thread maybe I just need new fork oil and a bit more of it.

Any recommendations on spring rate, oil weight, and oil height without making it too stiff and if I change the fork springs should I change the shock spring?

Ok so 100mm from the top of the outer tube with the outer tube pushed all the way to the bottom correct?? Again thanks for all the input guys. This is the first time I have ever done this.

426F...you are correct.

Dabernardi....according to Race Tech you should be good with the stock springs:

From RaceTech.com

Rider Infomation:

Type of Riding: Motocross

Rider Weight: 200 lbs.

Recommended Spring Rate: 0.460 kg/mm(use closest available)

Stock Fork Spring Rate (measured): .460 kg/mm(stock)

If your forks have never been serviced you MUST do it. Buy new seals and and oil and change them. You won't believe the difference. I run the stock springs and with a good fluid change the forks are plush but don't bottom....no headshake and no JACKHAMMER in the braking bumps.

I'm about the same size and I run 5wt Silkolene 135mm from the top (Factory settings) I've only bottomed the front end once, and I don't think anything could have soaked up that hit. The rear spring is one size larger (stiffer) than stock. I service the forks twice a year.

As far as bottoming Semics (MX instructor) says you should be bottoming about 1 time for every lap. As I understood this it doesn't mean hard but that would mean your getting the most out of your suspension, using the full travel and not just a portion. Makes sense to me.

Thanks for the tips. I'll try replacing the oil and seals first. I'm wondering if racetech is assuming a competitive rider would hurt their performance if the forks were set up slightly stiff where it might not for a slow guy like me??? Like I said I'd like to have the bike set up for jumps until I get better at them. After that I'll tune it for best all-around performance like cornering, etc. Got to get over my fear of missing a jump first...

I'll probably try a higher oil level but use the stock weight:

race-tech

BTW, here's an interesting observation on SAE fork oil weights:

http://www.trials.com.au/techtips/oil1.html

Hey, I am about 200 as well and am also pretty much a beginner. Definitely put heavier springs in the fork, I did and it is very nice. I happy with the stock shock spring. I run Belray 5wt at the stock setting and I am going to add it in 5ml increments to see if it improves bottoming. I am currently at 2 click harder than stock and would like to add oil and come back out to stock, or maybe softer. I had 10wt in for a while (it was all I could get in a pinch) and it was way to harsh. I don't think you are supposed to use the clickers as the main adjustment for bottoming resistance. The spring is your first line defense on that. Then starting at stock oil height and clicker setting see how that feels. If it bottoms alot, you can turn the clickers in and that may help but it will also make the small stuff a little more harsh. This is where I am right now. I am going to add some oil and see if I can back the clickers out. Oh, this is on an 02 426. Just my $0.02 worth.

Sorry to hijack the thread......

I'm a fat (little over 200lbs w/o gear) old guy (43) beginner, with a couple MX (actually AX) races in this year. I can only do a few of the very small jumps so I'm getting my butt kicked. Rather than go all out on the bigger jumps I've been just jumping a litte further each time. Well, that hurts and I notice my front end is bottoming out (not really hard though). I want to make sure if I miss the landing I've got something there to soak it up.

I'm on a stock 2001 426 (lightly used) with the compression clickers all the way in. Forks have never been serviced. Someone told me to order the stiffer springs (#42 I think) but after reading this thread maybe I just need new fork oil and a bit more of it.

Any recommendations on spring rate, oil weight, and oil height without making it too stiff and if I change the fork springs should I change the shock spring?

you need .47 fork springs and you will be happier

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