Air assisted forks Xj 550 1982

Hi.

I finally got my XJ550 up and running. A new swing arm arrived from Italy on Friday and everything looks and run great!

I pumped the front forks up to 0,5 bar, I found the specs in a old manual. They feel great. Took it out for a test ride. When i went down from the pavement to the street, a drop of ca 10 cm, the forks went soft. I stopped and checked the forks. Completely empty, no air left. Pumped them again, felt great. About 50 meters went in to a turn and they deflated again.

Are they worth trying to fix? I searched high and low for a renovation kit, but they seem to be non existent.

Are there any good replacement forks? I'm not interested in a full R6 (or similar) I want it to look stock and keep my twin rotors! May I rebuild them somehow without the air cushion?

Thankful for any intput!

 

US 550 does not have air forks. I would think an oring replacment or air valve replacment. also could leak from fork seals. does your forks have an air interconnect tube?
this is the 650 set up 2 orings and a valve.

 

Hi,

I'm not sure if it's original or aftermarket. They don't look quite stock somehow.

I haven't taken them apart yet. Just got a little carried away when the swing arrived and wanted a test ride .

I'm planning on taking them apart this week (vacation time is here and as I can't travel anywhere so I have five weeks in the garage) and see how it looks inside.

I think that I'll have to check with my local yamaha place and see if they can find any kits for it.

 

The first thing to do is find the leak, so you know what to get (it may just need new air valves).
Bring it up to pressure, and spray soapy water around the air valves, air collars, fork caps, and fork seals. If you see bubbles you've found the leak.

 

Commonest leak is the valve core(s) at the top of the forks. The valve carrier usually has an o-ring underneath it too, which will be old by now.
The fork cap o-ring leaks also, just to add to the fun.
When I ran US-market air forks on my GS, I had lots of fun. I really liked the way they handled, but the air leaks were a pain in the arris.
Just before I replaced the springs (the old ones were knackered) I took a swing at sealing everything on the fork tops and managed to keep air in for weeks on end.
That involved wrapping PTFE tape around the fork cap shoulder, around the valve holder thread, and replaced the valve cores.
I made up manual adjusters for fork pre-load, so that waved goodbye to the air caps, unfortunately.

 

you can try preload spacers, i don't have a 550 book with air forks but the 650 air fork has much shorter springs than non-air. so the spacers might not work if the springs are just too short.
maybe springs from a 650/750 might fit in 550 forks, don't think i've heard anyone trying

 

Thanks for all the answers. I sprayed a little bit of air tool oil into the valves and that seemed to fix the issue! They now retain pressure! The difficult part seems to be to not let all the air out when you remove the pump.. I need to be quicker!

 

You need one of these, which can be connected / disconnected without losing pressure. Far kinder to the forks too, than trying to delicately inject from a tyre air line - if that's what you were using. I held off on getting one for years, as the rear air shocks have sufficiently large capacity to cope with an air line, but I found the fronts really needed a proper tool.
I highly recommend this one.
https://www.amazon.com/gp/product/B006ID37ZS/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

 

nice tool not much more that a bycycle pump. good video on how it works on the ad

 

I used a regular bicycle pump. Just a cheap charlie one, so I did not use compressed air!

The one you linked to looks great! I guess I'll order one!

 

No air forks on any 550s as far as I know so I suspect aftermearket or forks off another bike

Saying that I bought a scrap rolling chassis off a guy in London some years back and I recall that had one fork with a tyre valve on it. The bike was a survivor though with a lot
of suspect parts on it