250R Fork oil question

[Fox250R]

Tearing apart my forks and the question I forgot to ask was what kinda fork oil should I be using? I have progressive springs and I'm about 200 with gear on if that even matters.

Just wondering what weight I should be using.

Thank you :)

[Red Rider]

I would use 15wt minimum. That worked great for me with my stock forks, but you're about 20lbs. heavier than I was. Probably 20wt max., and maybe experiment with the oil level a bit to tune to your liking.

[Fox250R]

I would use 15wt minimum. That worked great for me with my stock forks, but you're about 20lbs. heavier than I was. Probably 20wt max., and maybe experiment with the oil level a bit to tune to your liking.

Cool thanks! :)

Is there any type brand I should be looking for?

[El Camexican]

Is there any type brand I should be looking for?

Any name brand 20W fork oil will be fine, just remember to change it one in a while (say every 50-70 hours of trail riding). Do you know HOW to check the level?

[Fox250R]

Any name brand 20W fork oil will be fine, just remember to change it one in a while (say every 50-70 hours of trail riding). Do you know HOW to check the level?

I do not. :(

[El Camexican]

I do not. :(

Well let's fix that.

There are two ways to do it, volume and height. I like using both starting with volume.

Crack open your manual and find the fork oil capacity spec. Use a measuring device like a 2 stroke oil mixer or steal a measuring cup from the kitchen. Because you are rebuilding your forks from scratch the only oil in your forks will be from the light coatings you apply when you are assembling the forks, so you can pour the entire recommended amount in. You do this with the forks fully assembled and compressed, or bottomed out, but without the caps and springs installed.

Pour about 1/2 the oil in and then stop and work the fork leg up and down slowly a couple times. Then pour the other half in and pump the fork until there the movement or action is smooth and there is no sound of air or bubbles.

Now with the upper fork tube completely collapsed and the fork vertical (have a tape measure and a felt marker handy), take a clean wire, screwdriver, or any bar, or wire and lower it about 8" into the tube. Using the felt marker mark where the top of the inner fork tube is on the bar. Pull the bar out of the tube and measure the distance between the felt mark and the oil stain. This is your oil height, or level. Write it down.

At this time you should also measure the distance from the top of the collapsed inner fork tube to the rubber wiper that protects the fork seal. This determines where your forks bottom out in relation to the top of the fork. Write this number down too.

Keep all your adjustments and levels in a note pad for future reference.

The good folks at Honda gave you the oil volume as a starting point. Based on the 200# rider weight I see on here you will want to add at least 1/2" or 13mm of oil to whatever your initial level is. Measure the level again and duplicate it on the second fork. This is just to start tuning.

Now extend your inner fork tube all the way, drop the spring in and put the cap on. Repeat on the second fork and put the front end together. If you have air valves on the forks DON'T ADD AIR!

So you're all together. Using the measurement you got that tells you the distance from the top of your fork to the rubber wiper when it is bottomed out put a zip tie on the inner tube about 2" below where the fork should bottom out and go for a ride. At some point you'll hit something big, or make a jump and the rubber wiper will have pushed the zip tie up. You may even bottom out in which case the zip tie will not be needed, but assuming you don't bottom out and you have gone on a typical ride then the zip tie should end up within a 1/4" to 1/2" of fully bottomed out if you have the right amount of oil in the forks for YOU.

I was always told that my forks were perfect if I bottomed out once per ride and that I needed to add oil if I was bottoming out more than twice. I guess if I had a private mechanic on payroll I'd put him on it, but I don't and I'm too old to willingly bottom out my forks to make my mentors happy, so if I bottom out while setting up my forks I just pop the caps off and add a couple capfuls of oil to each side before the next ride and repeat until I don't bottom out anymore. Oh, set the compression and rebound to the middle of whatever adjustments are available and leave them there.

There is a lot more to suspension set-up, but on a 30 year old trike with limited spring options this is as good as you're going to get it (unless you have spring load adjustment on that trike?). That fancy rear shock of yours can be messed with till the cows come to roost. You'll want to read up on sag and get the spring set close before you take your first ride.

[6speedthumper]

I personally did what the Honda manual suggested and used ATF. Well, my manual is for my 350x, but, I decided to use the ATF in the R forks. They're the same basic fork, far as I've been able to tell. I'm about 200# with full gear and thus far I'm very pleased with the ATF over the fork oil I used when I first got the bike together. I don't recall what weight it was. May have been 15 or 20. But, anyhow, this is how my experience has been with the ATF. Although I am running 85 R forks on my 85 X... Don't know how much that plays apart in it. What with different rack angles, wheel base, weight, etc...

[Fox250R]

Well let's fix that.

There are two ways to do it, volume and height. I like using both starting with volume.

Crack open your manual and find the fork oil capacity spec. Use a measuring device like a 2 stroke oil mixer or steal a measuring cup from the kitchen. Because you are rebuilding your forks from scratch the only oil in your forks will be from the light coatings you apply when you are assembling the forks, so you can pour the entire recommended amount in. You do this with the forks fully assembled and compressed, or bottomed out, but without the caps and springs installed.

Pour about 1/2 the oil in and then stop and work the fork leg up and down slowly a couple times. Then pour the other half in and pump the fork until there the movement or action is smooth and there is no sound of air or bubbles.

Now with the upper fork tube completely collapsed and the fork vertical (have a tape measure and a felt marker handy), take a clean wire, screwdriver, or any bar, or wire and lower it about 8" into the tube. Using the felt marker mark where the top of the inner fork tube is on the bar. Pull the bar out of the tube and measure the distance between the felt mark and the oil stain. This is your oil height, or level. Write it down.

At this time you should also measure the distance from the top of the collapsed inner fork tube to the rubber wiper that protects the fork seal. This determines where your forks bottom out in relation to the top of the fork. Write this number down too.

Keep all your adjustments and levels in a note pad for future reference.

The good folks at Honda gave you the oil volume as a starting point. Based on the 200# rider weight I see on here you will want to add at least 1/2" or 13mm of oil to whatever your initial level is. Measure the level again and duplicate it on the second fork. This is just to start tuning.

Now extend your inner fork tube all the way, drop the spring in and put the cap on. Repeat on the second fork and put the front end together. If you have air valves on the forks DON'T ADD AIR!

So you're all together. Using the measurement you got that tells you the distance from the top of your fork to the rubber wiper when it is bottomed out put a zip tie on the inner tube about 2" below where the fork should bottom out and go for a ride. At some point you'll hit something big, or make a jump and the rubber wiper will have pushed the zip tie up. You may even bottom out in which case the zip tie will not be needed, but assuming you don't bottom out and you have gone on a typical ride then the zip tie should end up within a 1/4" to 1/2" of fully bottomed out if you have the right amount of oil in the forks for YOU.

I was always told that my forks were perfect if I bottomed out once per ride and that I needed to add oil if I was bottoming out more than twice. I guess if I had a private mechanic on payroll I'd put him on it, but I don't and I'm too old to willingly bottom out my forks to make my mentors happy, so if I bottom out while setting up my forks I just pop the caps off and add a couple capfuls of oil to each side before the next ride and repeat until I don't bottom out anymore. Oh, set the compression and rebound to the middle of whatever adjustments are available and leave them there.

There is a lot more to suspension set-up, but on a 30 year old trike with limited spring options this is as good as you're going to get it (unless you have spring load adjustment on that trike?). That fancy rear shock of yours can be messed with till the cows come to roost. You'll want to read up on sag and get the spring set close before you take your first ride.


Thank you so much for explaining it! believe I understand very well now and we be starting it in the morning :)

[Red Rider]

Wow, El Camexican, that's way more involved than the way I used to do it. I used a technique that was very similar to the first half of your recipe. Basically I just stood the forks up vertically, removed the springs, and made sure both had equal amounts of oil in them via measuring the level from the top of the tubes. Kind of makes me wonder how much better they would have performed if I had followed your complete recipe. :wondering

[El Camexican]

Wow, El Camexican, that's way more involved than the way I used to do it. I used a technique that was very similar to the first half of your recipe. Basically I just stood the forks up vertically, removed the springs, and made sure both had equal amounts of oil in them via measuring the level from the top of the tubes. Kind of makes me wonder how much better they would have performed if I had followed your complete recipe. :wondering

I didn't mean to overcomplicate the post, sorry if that's what the result was. Sounds to me like you had it licked as long as you weren't bottoming out all the time, but the thing is that if you have to much oil in the forks you aren't utilizing the full travel and you're missing out on a plush ride. No harm to anything other that your arms and back, but I love plush. I should have mentioned in the post that if you aren't using all your suspension travel you should remove a little oil. I picked up a nice leveling/adjusting tool a few years back. http://www.jpcycles.com/product/230-441?utm_source=PLAs&utm_medium=cpc&utm_term=&device=c&network=g&matchtype=&gclid=CMKe2N7Z8L8CFUoS7Aod8DAAOg Makes the job a lot easier.