Improving the handling of Yamaha XS-XJ 1100 motorcycles is a frequent topic of discussion. There are several articles and vendors who have contributed to these discussions; what follows is a summary of these past posts and URLs to other articles and vendor information.

Here is a post from Tkat regarding fork braces:

That wheel spinning down there is a Hell of a gyro. Twist the bars or lean the bike and s'thing moves --- typically the bars or the bike. BUT NOT THE WHEEL!! The gyro action is just too strong. And what's planted on the road and controls the direction of travel? That's right, Homer, the wheel! The result is "lazy steering". The weaker the connection between the input and the wheel, the sloppier the directional response. Long, skinny forks =weak link.

A F/B ties the legs together in the middle so the unsupported columns now act as a beam, hence increasing the stiffness of the now single member. Increased stiffness = more positive output/input ratio and the bike tends to go where it's pointed much more quickly. Conversely, if the wheel is "kicked" by a rut, etc. the H/B doesn't see the directional change as quickly as a stiffer column will.

And, OK, so you say you're not a boy-racer and don't power the machine through turns --- just a cruiser on Sundays. Fair enough. But what about that LOL in her USS Caddy land yacht that only sees that yard sale sign that requires a left turn? 'Nuff said.

And here endth the Beginning Physics 101 Lecture for the day.

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Many XSives agree that a Tkat fork brace is the best handling improvement for the money you can make to your bike. (LOL = Little Old Lady)

The second item to attend to is setting the suspension ‘sag’. This is the amount the bike will ‘settle’ with just the weight of the bike and rider on it, and is set in a static (stopped) setting.

For full details, see the excellent article at:

Basically, you need to measure the difference between the bike unloaded, all weight off the suspension, and loaded with rider and gear. It helps to have 2 helpers for this process.

Get the bike on the center stand with the rear wheel off the ground. Measure the distance from the axle to a fixed point directly above the axle, such as the fender or a frame point. Get the bike off the stand, and have the rider get on. With one helper holding the bike steady, the other helper should measure between the axle and the same point. Subtract the ‘loaded’ distance from the ‘unloaded’ figure. This is the rear suspension ‘sag’.

With the rider still on the bike, tie a cable tie around one of the front fork tubes, just under the fork seal. Have the rider dismount and get the bike back on the center stand. Get the front wheel off the ground and measure the distance between the cable tie and the fork seal. This is the front suspension ‘sag’.

Most articles indicate that the suspension 'sag' should be 1/4 to 1/3 of the suspension travel. This comes to about 1.6 — 2.2 inches for the front fork and about 1 — 1.3 inches for the rear. The figures are starting points, not absolute numbers, so approach the adjustments methodically until you get the best settings for your tastes. According to the specs for a ‘78 standard, front fork travel is 6.6 inches or 167.6mm. Rear wheel travel is 4 inches or 101.6mm. The sag figures are given for these specifications. Other models may be slightly different, but probably not by much.

Why is sag needed? It gives the suspension "travel space" when rebounding; the suspension will move past the initial starting point of the suspension into the sag area. With no sag, the suspension would hit against its rebound stops, making for a very uncomfortable ride and poor handling characteristics.

How do you adjust for sag? In the forks, many riders use short lengths of PVC pipe as spacers. Cut to length; the pipe is cheap and readily available. A 3.25 — 3.5 inch spacer is about average for most applications. If you install progressive-rate springs, the instructions will give you a suggested starting length. Bikes with full fairings or heavy riders may need longer spacers.

If you have air forks, increasing the air pressure can adjust sag. In the rear, increasing the shock preload is often the answer. An alternative is to get stiffer shocks or springs, available from various vendors such as Progressive and Hagon. URLs are given later in this document; see the Suspension Upgrades heading. Both sites have suspension-related tips as well.

Increasing air pressure and increasing shock preload to adjust sag have drawbacks, however. In both cases, the force needed to overcome the higher preload will make the suspension stiff and unable to react to smaller road irregularities such as expansion strips. The result is a harsh ride; increasing preload changes the initial force needed to get the suspension to move. The trick here is to not go overboard with air pressure or shock preload. If you have to use maximum preload, or over 5 —7 pounds of air in the forks to set the sag, you should probably look into modifying your suspension.

For an excellent suspension troubleshooting guide, see:

Next up is adjusting the steering head bearings. Get the front end of the bike off the ground. Move the handlebars from full left to full right and back. Steering should be smooth through the full travel, with no ‘dead spot’ or binding anywhere in the range. Grab the fork tubes and pull them forward and sideways; there should not be noticeable play. If there is some play, adjust the bearings using the service manual procedure. If there are rough spots or a ‘dead’ area (feels like a detent or notch) the bearing will have to be replaced. From a previous post by Denny Zander:

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For those who care: The following #'s are for the Timken steering head

brgs. to suit my SG. I'd imagine all the 1100's are the same.

Top: 32005X 92KA1

Bottom: 32006X 92KA1

I got these @ my local brg house --- $48 out the door for the pair.

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An easy item to check and experiment with is tire pressure. The bikes will respond to relatively small changes in tire pressure, so try several settings. Note: Use the tire manufacturer’s guides, not the owner’s manual settings, when possible. Dunlop recommends 40 pounds for the K491 Elite II 16 inch size for the rear, 36 pounds for front K491s. I ride with Vetter hard bags and a Windjammer IV fairing and run 42 PSI in the rear tire.

Dunlop has several tire tips dealing with selection, mounting, and maintenance.

While not strictly a handling issue, upgrading the brakes is recommended. Two items to consider: 1. Replace the old rubber lines with stainless steel lines and 2. Replace the brake pistons with new stainless steel pistons.

Several posted testimonials confirm the improvement in braking these lines offer.

Tom was getting around $12.00 each for the pistons. If you need to replace pitted or corroded pistons, these are to ones to get. Note: you may need to get new dust covers, piston seals, and dust cover springs to complete the job.

Most common replacement fork springs are the Progressive brand progressive-rate springs, and a similar spring is available from Hagon. These give a ‘soft’ initial rate to absorb smaller road imperfections, then get stiffer as the suspension moves farther for larger bumps or is ‘loaded’ by gravity as in a turn. Price is in the $50.00 range. Many people have recommended the installation of progressive-rate springs for improved handling and assure the rest of us that the installation can be done by most home mechanics.

The choice of replacement rear shocks is less clear. Koni, long considered the best of the high-performance shocks, dropped motorcycle shock production in late 1999 or early 2000. Existing products will be supported, however. The other major replacement shock companies are Progressive, Ohlins, Hagon, and Showa.

URLs are:

Of the 4, there is almost no information on the Showa page and very little on the Ohlins page. Considering Ohlins retail at over $700.00 per pair, this may not be a big issue. Most of the information available will be from the Progressive and Hagon sites. Hagon also has a US distributor, David Quinn Motorcycles, Inc.:

David Quinn

David Quinn Motorcycles

335 Litchfield Turnpike

Bethany, Connecticut 06524-3505

Phone: 203-393-2651

Price for a set of Hagon shocks plus shipping was around $200.00 in the fall of 2000. Part number 32009 fits most, if not all, XS and XJ models. If you are looking for a little longer shock, 13 inch instead of the original 12.5 inchers, specify a part number of 33009; the first 3 digits represent the length of the shock in mm. Options include black or chrome shock covers. Price includes springs.

In the Progressive brand, look at the 412/12 series or the 418/18 series. Part numbers are 418-1007 B/C, 18-1005, 412-4207C, or 12-1201B. (B = Black, C = Chrome.) Differences are in type and number of external adjustments. The 418 series sells for around $435.00 per set, and are top of the line from Progressive. The other models are less expensive.

Again, if you prefer a 13 inch shock instead of the OEM 12.5 inch shocks, Progressive recommends getting the 418-1026B/C or 412-4212C shocks for your bike. A 13 inch shock will allow you to use a lower preload, giving a ride that soaks up smaller bumps better.

The article contains information about spring rates and shock length as well as a good overview of upgrading the XS suspension. Since it was written in 1982, the solutions he advises are sadly out of date, but there is good information in the reading.

Consider this post from Dwight Delfeld (Dwight_Delfeld@mail.bankone.com):

and the task was done. It did lower the seat about 1/4", but that was okay with

me, as I am only 5'10". They have a better spring rate, and give a softer ride,

but still have a superior load carrying capacity by virtue of their 5 way

adjustable springs."

There may be other alternatives out there. In particular, several Harley-Davidson models use 12.5 or 13 inch shocks; if you have tried adapting these to your XS or XJ, please let me know the results.

The handling of the XS-XJ bikes can be improved quite a bit over stock. It takes some time and effort, but is a worthwhile endeavor. I hope the information in this note can help.

Jerry Fields

March, 2001