How do I adjust the rear suspension?

[robindean]

'82 XS400R here.

I bought this bike with the intention of giving it a sport-touring feel.

In short, I bought most of the "Recon" series from Rapid Transit (19 liter tank bag, 45 liter total saddlebags, 23 liter tailbag). These bags are all lightweight nylon and, when completely full, have minimal effect on the suspension ... not to mention they look really sharp

So, my sport grocer-getter is rockin' ... until! (que dramatic music).

When my wife (little thing, barely 120lbs) gets on, the bike feels low. When riding, most bumps get the needed suspension clearance but every now and then I feel/hear that big 'ol "THUNK" where there's just not enough room and the suspension goes frame-on-frame.

To better configure my bike for this kind of use, what should I do? How do I do it?

Are those big THUNKS harming my bike? Again, they are few and far between but my concern as a new"ish" rider remains.

 

[Joel]

Those "thunks" may be your tire hitting the inside of the fender. If there are any rough spots it could take some chunks out of the rubber. I'm not familiar with the XS400R suspension, but my '82 XS 400SJ (different setup) is pretty easy to adjust with a big adjustable wrench and a cloth to stop it from scratching the chrome.

 

[robindean]

Thanks for the heads up.

My rear suspension appears to be nothing more than a single bar at the tire.

Assuming we have the same base mechanics, is the info in the manual?

I'd love to learn how to do this.

 

[Joel]

I looked at the parts diagram on Bike Bandit for your bike and it has a basic monoshock system. Attached to the bar at the rear wheel (the swing arm) is a shock. It's tucked away in front of the rear wheel. Having just seen a few photos of the bike, I'm not sure what the best way to access it is. You may be able to get at when you bike is on its centre stand, by removing the rear wheel, or some other access point. Regardless, once you find it, all you need to do is twist it to tighten it. There will be notches that it can click to. If you're going with a passenger sometimes (as I sometimes do) I suggest the toughest setting. To tighten mine, I just used a large adjustable wrench with a cloth around the shock (to stop it from scratching the shock) and twisted it.

 

[robindean]

Very interesting, Joel, and thank you!

This may very well be my first "do it yourself" on any motorized vehicle, so I'm a little intimidated. Remove the rear wheel alone seems a little out of my comfort zone. I'll throw on some beater clothes and scrape around to see what I can see before going further.

If you have a link to the specs on this particular issue, I'd love to see it.

 

[robindean]

Hmmm ... readying up to delve into this and I think to myself: Which manual from the tech section do I look this up in?
Anyone?

 

[Joel]

Here's a link to the parts diagrams on Bike Bandit: http://www.bikebandit.com/houseofmotorcycles/1982-yamaha-xs400j/o/m8257
Before you pull the rear wheel off, make sure you can see the shock behind the wheel (the part with a big spring around it). Some bikes have different access points to adjust the rear shock. You should find shock adjustment in your manual, possibly in the section that deals with wheels and brakes.
If you do remove the rear wheel it's fairly straightforward. There are likely nuts on the ends of the axle. Loosen those, slide out the axle, unhook the brake, slide the rear wheel forward to pull the chain off the sprocket, and you wheel is free.

 

[robindean]

Very cool. I'll read up.

In your experience, does adjusting the rear suspension mean the front should be adjusted as well? Or ... am I simply adjust tension and the wheel position remains the same?

 

[darkside]

The rear shocks should have adjustment unless they are already at the highest setting. At the bottom of the spring there are two tabs that sit in a saw tooth or stair pattern slots. Thats your adjustment. Most you can gain is about 1.25"

Posted via Mobile

 

[Joel]

You're just adjusting the tension. No need to worry about the front. If that bottoms out, you'd likely have to get stronger springs for those. When you adjust the rear shock, the wheel will stay in the same spot.

 

[robindean]

This marks the first time I've ever (other than a tire change or oil check) done maintenance on a motorized vehicle and I'm pretty sure I got it so ... COOL!

I think I did it correctly but would love some verification.

I've attached two photos.

Basically, the access is directly under the seat (?) which both makes sense and doesn't to some regard.

I cranked the spring load to the max by COMPRESSING THE SPRING AGAINST ITSELF AS IF TO CLOSE A SLINKY to give it more tension ... NOT STRETCH IT OUT LIKE AN OPEN SLINKY ... right? That's the logic that made the most sense at the time ... basically, "push the spring together on itself".

Yes?
I'm no mechanic but, assuming I'm right I not only thank you but pat myself on the back for givin' 'er a go.

 

[robindean]

Oops ... forgot the photos! They are attached in this posting ...

 

[Joel]

I don't see the pictures but it sounds like you did it right. You'll have to take it out for a test ride with your passenger and hopefully that cures the issue.
Next thing you know you'll be ripping apart engines.

 

[Joel]

I see the pictures now. Looks good.

 

[robindean]

Feels excellent with both of us on the bike! Thanks for all of your help

 

[robindean]

This question is in conjunction with my suspension adjustment, so I'll go ahead and post it here rather than creating a new topic.

Now that I have the suspension cranked, the bike is feeling much better

One thing I'm noticing is how (and again, I'm a total mechanical newb), the rear tire appears to be on some sort of hinge. Even with the suspension adjustment, the bike looks as if the tire could be further from the fender. To clarify, the tire doesn't look like it's too close. It simply looks as if it COULD be further (?)

Is there an adjustment that will expand the distance of the tire from the fender? Sort of like "opening the door a little further" on the "axle hinge"? (My terminology is likely off)

Here are pics of my ride as she stands: http://www.xs400.com/media/albums/166/

 

[Joel]

There is, and that's how you adjust the tension on the chain. The further the tire from the bike, the tighter your chain. You want to have a little slack in the chain (my manual recommends 10 to 20 mm).

 

[robindean]

Alright.

I'm being told to look for other things as well.

I've since moved the topic here: http://www.xs400.com/forum/showthread.php?t=6321

Chime in

 

[Tannins]

Man, I've been asking this question all OVER the place. I thought the manual said it was under the seat....but thanks for the confirmation.

Can't wait to tighten mine up.

 

[regis411]

What tool did u use to tighten it