GSX750 Mods

**Anonymous** · 09-29-2003, 09:20 AM

Pete, since your bike is an '82 it has twin rear shocks, right? If it has a single rear mono shock with remote preload and rebound damping adjustment, it is equivalent to the '83 US GS750E(D). Either way, try backing off the preload to a "middle" setting, and the damping adjustment to the same (or slightly higher), for solo riding. Also, if the front fork has an air pressure adjustment, try setting it to between 5 and 10 psi. These settings should give you a "softer" ride.....you can then adjust them up or down from there to suit your preferences.

**Pete Logan** · 09-29-2003, 10:25 AM

Simon, thanks for the advice. The bike is twin rear shock, with the adjustments top and bottom of each. I'll try at mid point and see how it goes. FYI a friend who has also ridden it agrees that the bike as it is set up is quite squirrely on any surface imperfections at all (of which there are quite a lot here). Seems to want to follow every mark in the road surface. Is softening it likely to help with this, or is it just 'they all do that, sir' ?

I'll have a look at the front and read the Clymer manual (I know - sign of weakness:-)). It has anti-dive fitted, and an additional cross brace at the top of the lower fork (Tarozzi), but right now I don't recall seeing any adjusters.

**Billy Ricks** · 09-29-2003, 11:35 AM

Pete,
Check out this thread for a little info on suspension setup.

The GSResources Forums

http://www.thegsresources.com/_forum/viewtopic.php?t=13716

**Anonymous** · 09-29-2003, 05:23 PM

Originally posted by Pete Logan

Simon, thanks for the advice. The bike is twin rear shock, with the adjustments top and bottom of each. I'll try at mid point and see how it goes. FYI a friend who has also ridden it agrees that the bike as it is set up is quite squirrely on any surface imperfections at all (of which there are quite a lot here). Seems to want to follow every mark in the road surface. Is softening it likely to help with this, or is it just 'they all do that, sir' ?
I'll have a look at the front and read the Clymer manual (I know - sign of weakness:-)). It has anti-dive fitted, and an additional cross brace at the top of the lower fork (Tarozzi), but right now I don't recall seeing any adjusters.

Pete, to a greater or lesser extent, all bikes are "camber sensitive". That is, if there is a trough or groove in the road, the bike may want to follow it. A lot depends on the nature of the road irregularity, size and type of front tire, and the angle of the road feature to the direction of the tire. My personal record is involuntarily following tram tracks in Brussels, Belgium on a little Yamaha 125. 8O

With regard to surface irregularities of a bumpy or pitted nature, preload is important. If you have preload turned up way too high for carried load, the suspension may not react to these irregularities, with the bike tending to "skitter" across them. Simply put, a higher preload tends to require a bigger bump before the suspension compresses to "accomodate" the irregularity. The preload adjustment is intended to compensate for different weight loads (solo vs. passenger vs. luggage, etc.) so that the loaded bike settles ("sags") under load to an acceptable level, versus the unloaded height.....see the reference that Billy has provided.

On our GS's, the damping adjustment modifies rebound (not compression) damping. If there were no rebound damping, then the bike would "pogo" down the road as the spring uncompresses ("rebounds") after hitting a bump. Generally, it is necessary to adjust the rebound damping in line with the spring preload.

In general terms what I try to do is this: have the spring preload and damping adjusted so that it is soft enough to absorb road irregularities that might upset the tire/road contact (i.e. the tires following the road surface), without being so soft that the bike moves around on its suspension, perhaps causing weaving in a straight line, or wallowing in the corners. Since I am more of a sports rider than a cruiser, I tend towards the hard side of adjustment in the settings. However, it is possible to set things too hard (if lightly loaded) so that the handling suffers in the real world of imperfect road surfaces (as opposed to mirror-smooth surfaces).

**Pete Logan** · 10-01-2003, 06:39 AM

Fork Spring Adjustment

Thanks to both for your help. One last question - The top of my forks doesn't look like the manual. Instead of an air valve they have what looks like a mechanical adjuster screw coming through the retainer bolt, with a cover marked "SPRING ADJ". I put a spanner on one and gave it a squeeze. It moved around and down, seemingly against a spring. My guess is it works by moving from notch to notch to preload the fork spring, on the same principle as the rear end adjusters. It could be an aftermarket thing, or maybe was just fitted in Europe. I just wanted to get any opinions before leaning on it for real. I put the biggest picture I could get on http://webplaza.pt.lu/logan .

Thanks for any comments.

**Billy Ricks** · 10-01-2003, 07:01 AM

Those are aftermarket pieces and they do adjust preload. Just use them to adjust the sag. I believe they are Works Performance parts.

**Pete Logan** · 10-01-2003, 10:58 AM

Think I just lost a reply - so I hope this is not a duplicate.

Thanks Billy - I put a spanner on them and they seem to be simple two position adjusters, up or down with 1/4 to 1/2 inch difference in height. So I guess I'm not running any air.

Came across another interesting thing adjusting the chain slack - the right rear fork alignment was about three notches further back than the left, which must mean the wheel was not on straight.

I got almost all of it out by hand, but still have one notch different on the two sides. Does this matter (I assume yes), and is there a good way to push the wheel around ? Does it help to rotate the axle, or is this a bad idea ?

Thanks again to everyone

Pete

**Billy Ricks** · 10-01-2003, 11:39 AM

Don't go by the notches, they aren't always stamped right. Either use two long straight edges against the sides of the rear tire extending forward to the front tire to check the alignment against the front. Do a Google search on "motorcycle wheel string alignment". You'll find quite a few pages that describe how to do it with a string.

**Anonymous** · 10-01-2003, 01:49 PM

Originally posted by Pete Logan

.....Came across another interesting thing adjusting the chain slack - the right rear fork alignment was about three notches further back than the left, which must mean the wheel was not on straight.....

Pete

Pete:

Billy again has give you the best answer, so I'll confine myself to just one comment.

The tendency on chain-driven bikes is for the wheel alignment to be slightly "out" unless you are careful. The side of the axle with the chain on (left in the case of GS's) tends to be pulled further forward than the other side by the tension of the drive chain during the adjustment process, or afterwards if the bolts aren't torqued up to proper tightness. This probably is why your rear wheel was so grossly out of apparent alignment. The trick is too make sure that the screw-in alignment adjusters are fully butted up against the end of the swinging arm when checking the alignment, and during subsequent tightening of the axle nut......I sometimes give my rear tire a whack with a rubber mallet to make sure this is the case.

Simon

**Pete Logan** · 10-01-2003, 02:46 PM

Thanks again - I'll check tomorrow (out of light here).

Pete

GSX750 Mods

GSX750 Mods

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