How to service these forks?

Hi guys,

I need a little help regarding these forks on an '81 XJ550
They have a 32mm tube. and looks like someone in the past has had a grab at the schrader valve with pliers or something.

Anyway, I haven't seen these before and couldn't find anything via google.
What am I looking at here? Is this a removable cap because it looks fixed?
Anyone have any info on this type of top cap or how to service these things?

 

That is the valve through which the air-spring in the shock is adjusted.
The cap is removable.
Put the forks back into the triple tree.
Use a blunt object to press the cap down (because of the valve I'd suggest a deep-well socket), and a thin screwdriver or dental pick to pop the wire clip out (you can see the clip in your first photo).
Beware, the spring will want to release quickly, so be ready.

 

Legend k-moe!
Thanks so much for the detailed reply!

Paul.

 

Detailed!?
That was the footnotes.

 

I use one of these to remove the circlip. Wrap some duct tape around the end of the fork so the c-clamp doesn't slip.
As k-moe suggested you will need to cover the air valve with a socket. Screw in the centre threads against the socket then pick out the circlip.
Release gently as you have the fork spring pushing up, be careful here.

 

That clamp is perfect, to be honest I hadn't even seen one before, probably because I've never needed it. Found they stock them locally to me for 10 bucks so all good.

Small problem now is identifying exactly what fork I have to work out the oil amount. Everything I've seen so far points to this bike having a 35mm fork tube, but mine is 32mm.

I'm in Australia, and although that doesn't necessarily mean the bike originated here, I'm also trying to figure out which variant I have of this bike.
The one I have is a 1981 model and has the Maxim style tank and only a single left side caliper.

 

TECH TOPIC: Model ID and VIN's

 

I have another question regarding these forks if someone could help...

Mine are 32mm and everywhere I read they are 35mm, can't find anything referring to 32mm forks.

Does anyone know how much oil go into the 32mm forks?

 

Welcome aboard. You're gonna need a service manual.

Gary H.

 

32 mm correct. There are many sites that list the specs wrong.

This link should still work to get a manual.

http://www.4shared.com/file/16680550/631529a3/XJ550RH_service_manual_XJ550_RH_.html

 

Yep.

 

XJ550 Seca fork tubes are 35mm OD, The XJ550 Seca models are the "baby fork tubes" of the entire XJ series, which is very odd.

my xj550H maxim are 36mm

32mm is an odd size and with the disc on the left is a seca thing maxim is on the right as you sit on bike

the air valve is not a stock maxim thing. I did just see them on ebay for the 550

seca and maxim use different amounts of fork oil

maxim


seca

 

your photo shows axel in center of fork tube another seca
what size is your rear tire? 16 or 18 inch

110/90-18 rear is a seca tire

130/90-16 is maxim tire

swirley rims are maxim in US but seca in europe

you need to check the vin number link that was provided both frame and motor to properly ID the bike

 

Yes 32mm OD fork tubes are a problem..........certainly not correct for an XJ550 of any stripe, and the trick will be in figuring out what bike they came off of (so you can obtain the proper rebuild parts). They must have switched out the steering brackets, too............

 

Even the 400 Maxim uses a 35 mm fork?

 

He's in Australia, and I think he has a JDM import, so the fork tubes are likely correct. He'll also need a JDM manual, and learn to read Kanji

What I'd do is fill the forks to about 6" from the top of the collapsed tubes, then go for a ride and see what it fels like. The other way is to do some math to figure what the height of the oil column is in the 35mm forks, and scale that down to suit the 32mm forks.

 

+1.

Gary H.

 

Thanks for all the replies and suggestions.
I have a manual for the bike, but it only points to the 35mm fork so no luck there.
I have matching engine and vin numbers, and using those points my model at being the H variant, and it only has the one brake/rotor as well.

The other thing I might try is finding another Yamaha that might use the same fork type?