Fork seal time

[old_skool]

Ordered my fork seals and plan on replacing them soon, question is what weight would you recommend,15? whats the pvc mod about I've briefly encountered? I plan on keeping the stock fork assy, just want to make it decent for 2up riding, which will most of it, and even when not, I'm a big guy-6'1" 260#+, wife 120#.
I plan on adding the fork brace, would like to keep the factory springs intact.
And any other easy mods ok, but don't want to be machining or changing components from another bike setup, and $$ is a concern at the moment, but would rather wait if it becomes necessary to spend more $'s than expected.
79xs1100SF with air/oil forks. Is there any special seals besides the oil I need to be concerned with that would affect the air assist to function or not?
Thanks in advance! Rich

[XS1100_OEM4ME]

Fork Oil

I would stay close to the 10w fork oil if you intend to ride in Ohio winters much 15w OK, easy to change to 20w if needed in the summer Phils PVC fix wouldn't hurt with the weight load of 2 up and the springs being 30 years old. I would turn up the rear shock load springs next to highest load to start and play with dampers till they sute your tast and ridding style. Don't go nuts on the front fork air presure, you can blow out your new seals with one blast of too much PSI

Ordered my fork seals and plan on replacing them soon, question is what weight would you recommend,15? whats the pvc mod about I've briefly encountered? I plan on keeping the stock fork assy, just want to make it decent for 2up riding, which will most of it, and even when not, I'm a big guy-6'1" 260#+, wife 120#.
I plan on adding the fork brace, would like to keep the factory springs intact.
And any other easy mods ok, but don't want to be machining or changing components from another bike setup, and $$ is a concern at the moment, but would rather wait if it becomes necessary to spend more $'s than expected.
79xs1100SF with air/oil forks. Is there any special seals besides the oil I need to be concerned with that would affect the air assist to function or not?
Thanks in advance! Rich

[old_skool]

Riding will be April through October. does someone have a link to the pvc mod? Didn't see it in the modification section and I don't have too much luck with the search engine.

[jetmechmarty]

You can put a piece of PVC pipe on top of your spring to increase preload. You're looking for approximately 35-45mm of laden sag. With the load you're carrying, you'll need some more preload.

Oil viscosity in your forks controls the rebound and dampening. The lower the viscosity, the faster the rebound. I had 10W in mine and I'm switching to 15W, but mine has emulators. 10W was too harsh for me. In mine, the viscosity only controls the rebound.

[old_skool]

what do emulators do? and what size piece of pvc, any pics or drawn diagrams of exact placement?

[XS1100_OEM4ME]

Fork

This might be helpful to you:

http://www.xs11.com/forum/showthread.php?t=33751&highlight=pvc

[jetmechmarty]

what do emulators do?

The easy answer for me is to send you a link. They're a rather expensive upgrade. In my case, I find them worthwhile.

HOW EMULATORS WORK

and what size piece of pvc

To set up the stock forks, buy a short length of PVC pipe. I think it's about an inch in diameter to sit on your spring. You're going to use very short pieces. Decide first, do you want to set it up for just you or for you and your wife. Since she's so small, you can probably get away with setting it up for just you.

First, raise the front of the bike. Take a measurement from the top of the slider to the lower triple tree. Now, you need help. Get someone to hold the bike while you sit on it. Have someone else take that same measurement again. Subtract that from the first measurement. The difference is your "laden sag". You want that number to be approximately 35-45mm. If it's much larger, you should increase the preload with a spacer.

Remove your fork caps. Put a short PVC spacer on top of your spring, maybe one inch long. Put the cap back on. It's going to be very tight and it's a challenge with the air caps. Do the same thing on both forks.

Once that's done, go through the procedure of checking the laden sag again. Adjust the length of the spacer according to your needs.

If you decide to go through with all of this, we can talk about accounting for sticktion later.

[old_skool]

Will I be needing the damper rod tool for seal replacement? Is that to remove it, or hold something in place while something else is loosened....sorry, never had a set of forks apart before, but going to do it just the same. Now a piece of pvc goes on top of the spring, to what, partial compress the spring for stiffnes?
What size and thickness? Have read the manual several times, so a little familiar with the components, just doesn't mention this tool.
EDIT:
Ok, read your post(was posting at same time) got the pvc thing down, and yes , I will be going through that. might as well go ahead and hit me with "we can talk about accounting for sticktion later. " As I want to be as informed as possible before I start, believe me, I can absorb it all, always was kind of studious that way, read a book, and practically memorize it.(helped in school) and a little history, wan an ase auto tech and helicopter mechanic, just never a bike mech till now...lol

[old_skool]

Ok. read up on how the emulators work, sounds like I'll do some riding first to determine how much need for that will be, I'm thinking that will be next winters project, and being that I'll be riding a lot of longer trips versus shorter, there may be a good need for low and high speed dampening improvements.

[jetmechmarty]

Sticktion

In the forks, there is some friction. We should account for that when we measure "laden sag". Remember, you're sitting on the bike with your feet on the pegs. (maybe your wife is on the pillion) We have the extended measurement. Before we measure with the load, push down on the handlebars and allow the forks to rise. Take the measurement. Now, pull up on the handlebars and allow the forks to fall. Take the measurement. The difference between the two is caused by sticktion. Add those two measurements together and divide by two for an average. Take that result and subtract it from the extended measurement. That is your laden sag, accounting for sticktion.

You should run through this same procedure at the back end, with the shock springs. Get this right, you're going to be much happier with your ride.

With that spacer, we aren't changing the spring rate, just taking up some slack in the compression. It's the same as adjusting the preload on the shocks.

If you are unable to get the correct laden sag, you will need new springs with a higher rate. That's where I went with mine. I'm 235# and my springs were sacked. We can talk about that later if we need to go there.

[old_skool]

Think I got it, appreciate it, now, will I be needing these so called bolt/nut combo special tools just doing the seals?

[jetmechmarty]

will I be needing these so called bolt/nut combo special tools just doing the seals?

Nope. No such thing for your Special. We're working on a Special? Loosen the 6mm allen bolt on the bottom of your forks before you take anything loose. I just went through this. One of mine wouldn't cooperate. BikerPhil turned me on to the right tool. A BROOMSTICK!

If you go to the link I posted, "HOW EMULATORS WORK", you will find detailed drawings of how your fork functions and how it is assembled.

[old_skool]

Special, loosen, no need to remove? Damping rod bolt right?

[jetmechmarty]

You may go ahead and remove it. Drain the oil first. More oil is coming when you remove that bolt. That's the only reason I said loosen.

[old_skool]

Thanks everyone a bunch, actually sounds relatively easy....famous last words