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Jay-Impala-man
3rd December 2004, 07:00
I turned mine into them. Just drilled some holes and put in some air valves and I am now riding on air! And no leaks! 13psi is just right. Using the sorry ass stock springs. A cheap and good trick! The ride is just great! If any one would like to go with air, let me know, and I will give more details. Jay-Impala-man

sportymark
3rd December 2004, 07:28
I cant believe youd have the balls just to drill into the forks! If my wife saw me doing that to my new bike she'd go bananas!

I think I'd prefer to pick up a set of s/h Sport forks.

Well done on the conversion though!

thunderpaw
3rd December 2004, 23:01
Yeah, I did that with my Husqvarna, too, 31 years ago. Worked okay. At the time, the idea was to replace the fork springs, not augment them, with air. Got many miles out and lost pressure...bummer. Keeping the springs, too, was the eventual way to go. I had mine set up so that both legs were equalized and filled at a single point. Only cost a few bucks worth of Weatherhead fittings, and is easily done. Air, as a spring, is naturally progressive.

Kim

SportsterBart
3rd December 2004, 23:21
Jay, did you take the fork caps off first before you drilled them?

I'd be concerned about metal shavings in the forks. Never had much luck with air shocks on my dirt bikes, worked okay on my GPz tho.

Bart

Jay-Impala-man
6th December 2004, 02:48
Yes, I took off the caps 1st. and took them to a shop who does great machine work. He just drilled and tapped the caps and put in air valves that I got at a parts store for $3.99 ea. I then put on some dice that I got at Auto-Zone for $4.00. I put 13psi into each fork leg. Works great! I did put in 15w Bel-Ray fork oil. The socket to fit the chrome nuts is hard to come by for some reason. But I got one for $10.00. I have been on a toy-run today and 3 Sportster folks ask me about my air forks. I have been told many times that Sportster forks and shocks suck! They do!!! 2004 Sportster 1200R. Jay-Impala-man :tour

wowee1
6th December 2004, 02:54
I did that with my '74 TS250 Suzuki...Gotta watch not to put too much air in there..Worked great though, now that I remember.

Jay-Impala-man
6th December 2004, 02:57
Yes, you keep the springs in there. They are just now getting air now. Jay-Impala-man

picowatt
13th December 2004, 23:55
Hey Impala man. I am very interested in this mod. Sounds very basic. but very effective. Do you have any pictures

flathead45
14th December 2004, 00:09
I had air forks on my shadow and there was a warning sticker on there that said not to go over 6 pounds of air pressure

just a thought ....

skooter
14th December 2004, 00:18
I remember doing this trick years ago on our dirt bikes. It worked real good even for hard use. I forgot all about it.

Great Idea and real cheap too.

Can't do that on my 1200s forks though. I've got the adjustable spring preload on the top of my forks along with the Rebound adjuster. I don't have a need for this. But if I didn't I'd be heading out to the shed right now!

Ronn39
25th April 2006, 03:40
Hey Impala man. I am very interested in this mod. Sounds very basic. but very effective. Do you have any pictures

I too would like to see that.

Jay-Impala-man
25th April 2006, 09:56
To everyone who replyed to the air forks subject that I posted before, Thanks for all the input that everyone gave. And now I will give a up-date on this subject. I first put in 13psi. It took 6 months to leak down to about 4 psi. I now have 15psi in each leg and believe me, they work great. Don't have a way to make pics, but it works and is cheap!!! It looks like they came from the factory! And everyone just thinks how great some air can work so well. It feels great to put on the front brakes hard and not have the front end doing a dive like before. Thanks again for the reply's. Jay-Impala-man

bplinson
25th April 2006, 10:13
This is a neat mod. You don't have any oil in your forks?

a45junkie
25th April 2006, 12:48
na you leave everything else in there, you just pressurize the airspace above the oil. it doesnt take much air, use a hand pump
but it is hard on the seals if they are not designed for it

lagerdrinker
25th April 2006, 12:49
jay, im not sure exactly whats going on here. you drilled caps, still have springs and still have oil. what you did is pressurize the air in the forks? there is already a pocket of air in the forks otherwise the forks would be hydrolocked and basically solid. i guess works like preload? did it raise the forks any?

lagerdrinker
25th April 2006, 12:50
a45 just answered two of my questions. posted at same time

sportysrock
6th December 2006, 03:50
To resurrect an old thread ...

Any new updates Jay-Impala-Man? How is the air fork mod working out for you? Has anyone else done this mod, and how is it working out?

Thanks!

Jay-Impala-man
11th December 2006, 05:27
Yes I still am enjoying my air forks. I do lose about 3 or 4 psi every 3 months or so. And it will bring up the front end some. I am running about 9 psi in ea. fork leg right now. Fork seals are not leaking. I did this mod over a year ago. So there you have it good people of Sportster land! And remember, "Jesus is the reason for the season" Jay-Impala-man

jms969
16th December 2006, 04:42
I turned mine into them. Just drilled some holes and put in some air valves and I am now riding on air! And no leaks! 13psi is just right. Using the sorry ass stock springs. A cheap and good trick! The ride is just great! If any one would like to go with air, let me know, and I will give more details. Jay-Impala-man

I use about 5 psi in mine with progressive springs, 15wt oil 5.5" from the top...

I did my 1st pair about 30 years ago on a Husky, never looked back :clap

sportysrock
16th December 2006, 14:52
COOL! Another one. It's time to accumulate a few more parts.
Thanks for the replies!

xllent01
16th December 2006, 15:00
Air is nice, nitrogen is better, too much will blow fork seals, best to keep in the lower range 5-8 PSI.

rottenralph
16th December 2006, 15:15
The new forks I have are air assisted as well. It is used to fine tune the feel of the front end. The reccomendations I got was to start with 3 pounds and see how it feels and go from there. The air preloads the front end and takes up some of the performance slop. A fork with ten psi is hard to compress than a fork at atmosphere. Everything else in the fork stays the same(if you have old fork seals you should probably change them first or they will leak down quicker and maybe not evenly).. For twenty bucks you can try it and see if it improves your ride. If you don't like the new feel of the front end you just let the air out and still have an interesting convesation piece.

snowman
16th December 2006, 15:59
Air is nice, nitrogen is better, too much will blow fork seals, best to keep in the lower range 5-8 PSI.

I just added 1" spacers to my custom front end and will get the parts to pressurize this week. Like the nitro idea. Can you get this in a can somewhere??? :geek:geek:geek

xllent01
16th December 2006, 16:42
I just added 1" spacers to my custom front end and will get the parts to pressurize this week. Like the nitro idea. Can you get this in a can somewhere??? :geek:geek:geek

Nitro is nice cause it's not affected by heat like air, just think of a car tire.

Besides all piggy back shocks use nitro cause of the ill effects of air.

Alot of car stereo shops that sell import hop up and go fast parts sell nitro to put in your tires, just take one of those 20lb air tanks you can buy at W-Mart or auto parts place and tell them to fill it up.:tour

DougT
16th December 2006, 19:50
Sorry to be the bearer of bad news, but converting forks that weren't designed to run air is way bad. This modification causes a condition called "stickshion", which basically binds up the operation of the forks. I also understand that air pressure in forks that weren't designed to run air pressure can cause the forks seals to blow out. They used to sell do-it-yourself kits to convert forks to run air back in the late 70's and early 80's, but I believe this practice went away for these very reasons. 13 lbs is at least double the air pressure maximum that I've ever seen listed for forks that were desigined to run air. Good luck!
DougT

xllent01
16th December 2006, 20:46
Sorry to be the bearer of bad news, but converting forks that weren't designed to run air is way bad. This modification causes a condition called "stickshion", which basically binds up the operation of the forks. I also understand that air pressure in forks that weren't designed to run air pressure can cause the forks seals to blow out. They used to sell do-it-yourself kits to convert forks to run air back in the late 70's and early 80's, but I believe this practice went away for these very reasons. 13 lbs is at least double the air pressure maximum that I've ever seen listed for forks that were desigined to run air. Good luck!
DougT

It's called Stiction, Stiction, or static friction, is friction that exists as the fork sliders rub against the stanchion tubes. ...

Stiction is when fork tubes are not aligned together because of wrong fork seals, bad settings or even damaged fork legs.

snowman
16th December 2006, 21:01
Guess I'll try the air thing first, before the nitro. I'm anxious to see how much dive this cures, along with the spacers...:geek:geek:geek

Mikel_NY
17th December 2006, 02:56
Here is a picture of mine I have been using Bel-ray 20 weight and 4-5 lbs of air. I am 170lbs and like a firm front end ( no pun intended ) 9166

Tater
7th December 2009, 23:25
I was wondering if some of y'all would come back on the air shock mods., as it is 2 yrs. old and let us know how things have worked out...??? You know, the good, the bad, or the ugly...
I did a search and found this thread as I was thinking strong about doing the air myself this winter...
So, thinking maybe if I bump it I'll get more and recent info...
Thanks and have a good one...Tater...

DEEP DIVER
7th December 2009, 23:40
And me.
They were fitted to a suzi I had 9 years ago and were great.
Put progresives springs in them and used to run at around 5 to 6 psi.
Made the ride smoother, with no air the front was twitchy.

XLXR
8th December 2009, 05:54
Air forks are just one way to tune the front end. It compensates for weak springs. 13 psi is too much, and so is 20 w oil. That combination would make the forks very stiff and cause the tire to skip over bumps and loose contact with the road. Not a good thing, especially in the corners. 5 psi and 10w oil will be much more compliant.

Read the "7 Pages of Suspension" in the Suspension Sticky Index for more information on how to properly set up forks.

Headly
8th December 2009, 07:34
I use about 5 psi in mine with progressive springs, 15wt oil 5.5" from the top...

I did my 1st pair about 30 years ago on a Husky, never looked back :clap

put a pic up, I think this will be a mod for me- I liked it on the 900F Honda

I have progressives w/ 12.5wt oil- it is a bit harsh, I should go softer a step.

Tater
8th December 2009, 11:59
Air forks are just one way to tune the front end. It compensates for weak springs. 13 psi is too much, and so is 20 w oil. That combination would make the forks very stiff and cause the tire to skip over bumps and loose contact with the road. Not a good thing, especially in the corners. 5 psi and 10w oil will be much more compliant.
Read the "7 Pages of Suspension" in the Suspension Sticky Index for more information on how to properly set up forks.
Thanks, sounds good to me...
What weight oil comes in my stock forks (09 1200C)...??? It does seem like a mite thicker oil might help, both ride & seals leaking...
I suspect that the lower pressure (5#) would be easier on the seals also...
Thanks and have a good one...Tater...

hdxr1200
8th December 2009, 12:21
Going to get some caps and have some valves put in them. I am really concerned about blowing the fork seal.If I keep the pressure low,am I worring to much?I am happy with my Progessives and fork brace.But should I try it/ Do I have much to gain???

Tater
8th December 2009, 14:55
Going to get some caps and have some valves put in them. I am really concerned about blowing the fork seal. If I keep the pressure low, am I worring to much? I am happy with my Progessives and fork brace.But should I try it/ Do I have much to gain???
I have about the same concerns, and am thinking I may try a tad thicker than stock oil + maybe progressive springs if I can find them (I already have a fork brace)...
I tried to find the progressive springs on the HD site for my 09 xl1200 C, but to no avail...
Does someone have a HD part number, or do they come from someone else, if so who, and which ones are best...???
BTW-XLXR that read the "7 Pages of Suspension" in the Suspension Sticky Index was a great help...
Thanks and have a good one...Tater...

XLXR
8th December 2009, 16:38
Progressive Suspension makes the replacement fork springs. I like the Works Dual Rate springs better because they can be adjusted, but are more work to get adjusted. There are links and explanations in the "7 Pages of Suspension" in the Suspension Sticky Index. I don't think Harley offers any replacement fork springs except for their lowering kit.

Set rider sag correctly and stay with 10w oil and increase oil level to control bottoming.

Adding air pressure to the forks is not a Harley recommended modification. Take your best guess about air pressure. I suggest getting the proper spring first and then use the air pressure to fine tune. I have not heard of any fork seals blowing out, but that doesn't mean yours won't be the first.

Do I have much to gain???

I tell people if you are satisfied with the forks, do not do any more modifications. If they are not working well for you, then you have to learn about all the different ways to tune forks and decide for your self.

One advantage of air forks, is you can very easily change air pressure to match different riding conditions. Solo vs two up. Smooth highway vs rough country road.

Tater
9th December 2009, 12:57
I think I will go with the Progressive Suspension springs P# 11-1525 as it seems that would be the most simple, and the fact that I put the progressive springs in my 06 vn750 Kaw. and they seemed very good... Plus a bit heavier oil, probably 10 wt....
I can get them through Amazon & Powersport Super store for $70.19 delivered which seems like a good enough price...
I can always go to a bit of air later, or even a heavier oil, or more pre-load if needed...
Does this seems ok to y'all...???
If so I think I will order the springs right away...
PS-Since no negatives, order placed, thanks...
Thanks and have a good one...Tater...

badcop2311
13th December 2009, 05:02
2004- 1200 R worst front suspension I have ever ridden. Put progressive springs in.made very little difference.drilled & tapped caps in 2006 wow made big difference. I run 8lbs air on each leg works fine.loses 2lbs over 3 months. replaced seals in 2009 they were looking a bit weepy.:tour

PaulDM
13th December 2009, 05:18
Just a cautionary note: I used to work in shipyards and watched a rigger doing an air test on a compartment, and he wasn't paying attention. He ran the pressure up to 5lbs and destroyed three compartments, it was supposed to be around 2 - 3lbs! and hold for a half hour. I'd think you'd be wise to start low and gradually get to the pressure your happiest with, just to be on the smart side!

semjpm
13th December 2009, 05:57
I'm planning on doing this mod. One thing that I have noticed is that anytime I remove and reinstall the fork caps the bike seems to ride better for a few weeks. I suspect that having the forks fully extended and replacing the caps provides some small amount of positive air pressure once the bike lowered back down. The plan is to get a baseline reading once the valves are installed and work from there.

SEMJPM

XLXR
13th December 2009, 15:48
I'm planning on doing this mod. One thing that I have noticed is that anytime I remove and reinstall the fork caps the bike seems to ride better for a few weeks. I suspect that having the forks fully extended and replacing the caps provides some small amount of positive air pressure once the bike lowered back down. The plan is to get a baseline reading once the valves are installed and work from there.


This is true. In order to get the fork cap back on, the forks need to be fully extended. Once you drop the bike off the jack, you can let the pressure out with the valves. If the springs, preload, and stiction are on the soft side, the forks will drop a bit when you let out the air pressure.

Keep in mind, the size of the air chamber above the oil level has an effect when adding air pressure. If you are adding air valves to the forks, keep the oil level at stock recommendations. You want a large air chamber to allow for a more progressive change in resistance to compression.

badcop2311
13th December 2009, 15:50
When i done the air mod in o6 talked with a Harley mech at Sturgis SD he stated that this was nothing new people had been doing this for years. He also cautioned me about the pressure, keep it 10lbs or less.Remember what happens when you hit a bump or pothole .the forks compress very fast you could have a presser spike of 50lbs or more.So remember as the forks go up & down the pressure changes.

unionthug
5th January 2010, 21:53
I too have done this mod on past bikes and plan it for my cafe style xl. I found a flush mount valve stem which looks really clean. I'm worried about 13 psi. That's a lot of air.

Michael

semjpm
5th January 2010, 22:15
Quick update: Ordered the new front caps, new o-rings, and the Harley suspension pump. Picked up the schrader valves (chrome ones from Ace hardware) the correct tap and a 21/64" (Q) drill bit. Once all of the parts are in, I will do the mod and post some baseline results. The plan is to use the recommended amount of fork oil and get a reading on the forks once the bike is off the jack. I suspect that I will see 3 lbs or so without pumping up the air pressure. That reading will give me basis for increasing the pressure.

SEMJPM