Quickening up the steering

[kerryg]

I have an old GSXR1100J (a reckless and impetuous purchase...but that's another story). Now it doesn't steer like a modern sports bike, and it needs to be wrestled around corners a bit...but I was surprised when I rode it the other day just HOW unwilling it is to turn at low speed (e.g. turning right into a side road from a standstill). I've searched around on the net and the amount of information on the subject of suspension set-up and different tyres and trail and rake...and I am bamboozled. The complexities of it all are beyond me. I would like to sharpen up its steering a bit. One thing that occurs is that it's running a slightly wider rear tyre (a 170 instead of a 160) but I doubt that that is likely to have much influence..but what do I know? The front is standard (a 110). I don't see how I can change the steering geometry, and don't really want to mess with the set-up too much in case I do more harm than good (these early GSXR1100s killed a few people, including racers, with their scary handling...I'd hate make it worse!) but thoughts include perhaps dropping the clamps down the forks a bit or going to to higher aspect ratio tyres (to get a more rounded profile) or narrower tyres...Anybody got any wisdom they'd share with the technically illiterate????

[duckman]

Now I'm no setup guru (my bike will attest to that) but you should set your sag first. (very important) and then raise the rear a little at a time until you get the sharper steering balance.

[scroter]

theres heaps you can do and yes a fatter rear tyre than original would slow the steering down. this is were id start cause it means no modification to the bike. other things you can do is
1. drop the triple clamps down the forks however i would only recomend doing this on upside down forks bacause on conventials you could bottom the suspension on the clamp an then you would be skating down the road.
2. put a spacer on top of the rear spring therefore raising the rear ride height without messing with the preload.
3. check your rear tyre pressure it may be too low.

[F5 Dave]

They were renowned at being a triffle flexy/wobbly. The Wider tire will be taller making it a bit higher at the back but over tyreing rims makes them steer badly & actually puts less tire on the road as they balloon a bit. You should really have a 5 – 5.5 inch rim for a 170.

Std size tires are good for that reason. Some tires will make the bike steer quicker than others. A new set of tires after a squared off rear will make the bike feel like it steers with footpeg influence alone in comparison.

The steering head bearings are well suspect of causing problems on these bikes. People can crank them up hoping for some extra stability but a damper is the go here. Take the forks out & you will really feel what the bearings are like, notches are caused by old age, wheelies & buggered discs.

Attend to the suspension. Measure the sag, re oil the forks & shock. Check the rear swingarm linkage is not sloppy (it will be). These will all help.

Then start dropping the forks through the clamps a bit to help things along, but really functioning suspension (& maybe a steering damper) is required before you get things turning quick safely.

Aligning the wheels with a straightedge will show how far out the swing arm adjuster marks may be which will affect stability. I am still betting on the str brgs & linkage lower brg being collapsed.

Easy enough to fix though.

[F5 Dave]

theres heaps you can do and yes a fatter rear tyre than original would slow the steering down. this is were id start cause it means no modification to the bike. other things you can do is
1. drop the triple clamps down the forks however i would only recomend doing this on upside down forks bacause on conventials you could bottom the suspension on the clamp an then you would be skating down the road.
2. put a spacer on top of the rear spring therefore raising the rear ride height without messing with the preload.
3. check your rear tyre pressure it may be too low.

1. Makes no difference usd or not, but do pay attn to how close things get.
2. A spacer on the spring will change preload. Perhaps you mean if the bike has an thread & nut top mount you can space it up with a spacer, but it will have eyelet either side. Shorter dogbones in the linkage will raise the rear.
3. Good point both ends.

[sedge]

Hey Kerry,

After riding your last bike I'd start with tyre pressures and suspension set up ;)...

Seriously, set the sag and wind up the preload at the back, if that's not enough I'd look at changing the rear linkage for a little more rear ride height, this will sharpen the steering at the expense of straight line stability, then add a steering damper to stop it shaking and you are back to square one ;).

I'd tend to shy away from dropping the forks through clamps coz unless it's a race bike it will reduce ground clearance on the road, I'd rather it turned a little slower than grind bits off or dig them in !.

A 170 over 160 tyre shouldn't be that noticeable, depends on profile I guess, a pointy tyre like a supercorsa will turn sharper than a tourer like a sportmax.

Didn't the 1100s have a steering damper built in ?, is it still working OK ?, IE not full of treacle instead of oil ?, I don't think they were speed sensitive like the more modern ones so could cause odd issues.

Cheers Kerry,

Sedge.

[scroter]

2. A spacer on the spring will change preload. Perhaps you mean if the bike has an thread & nut top mount you can space it up with a spacer, but it will have eyelet either side. Shorter dogbones in the linkage will raise the rear.
.

yep thats it.

[F5 Dave]

To check the rear linkage tilt the bike on the sidestand & balance on you hip, left hand on bar. Grab the rear wheel with the RH & pull. From new depending on the bearing & how much grease there will be 0-5mm play up & down. 5mm or more will requier a check. Any more will mean the rollers in one or more of the linkage bearings have decided to give up the ghost. New bearing & any marks on the spacer will mean replacement, no option. Unless you take the option of skimming it down & custom turning up a phosphor bronze bush.

[kerryg]

Well thanks guys for all the advice. It gives me a few things to look for. I think my plan will be to start with the cheap options first.

Sedge's unkind suggestion that I should first put air in my tyres implies a certain level of stupidity on my part (quite untrue of course :mad: )...but then suppose I SHOULD start with the obvious, which then leads of course to issue of sag ....OK, I'll restrain myself......yes, I will measure and adjust my sag.... and check for play in the steering head, swingarm pivot and rear shock mount and remedy anything needing attention...then check/replace oil in forks and check steering damper operation.

Then if no further problems found and still no improvement I'll try raising the rear a little bit with a spacer or shortened dogbones or summat...and maybe switch to a 160 section rear tyre.

After that...I'll give up I think. The options then start to get expensive, so I'll learn to live with it or buy a different bike!

Thanks again for some useful input (except you, Sedge :msn-wink: )

[F5 Dave]

Let us know how things progress. As you will be aware there are a million clicker adjustments to play around with but getting the bike in the right attitude preloadwise will help put you in the ballpark.

You won’t be able to ride height adjust with a spacer as the shock is eyelet to eylet & the top mount will be welded on I reckon, however suzi’s of that age probably have dogbones made of flat steel. Getting a chap to cut a couple out on a industrial guillotine or bandsaw may not be too hard & then just drill them with the holes closer together. At a guess 2mm closer will net 10mm ride height assuming 5:1 ratio at that point of the curve. Don’t skimp on the thickness & drill them together so they are the same length of course.

[DEATH_INC.]

Give her a good once-over,new oil in the forks/shock will help no end and should be the first step into improving the handling on an older bike.Fit a damper before you start to try to speed up the turning(if it dosen't have one already).Raising the rear is preferable to lowering the front you can run out of ground clearance and it lowers the c of g which means you need to lean further to turn,but don't go too far,you'll upset the swingarm angle/squat too much.Try a lower profile front tyre,it'll make it turn in quicker.If all else fails and money isn't an issue,get some adjustable clamps made up,or fit offset spacers into the steering head and steepen up the front/reduce the trail.

[AMPS]

It may sound obvious, but when people talk of dropping the forks in the yokes, they're only talking a few millimetres.
Lou

[kerryg]

[QUOTE=DEATH_INC If all else fails and money isn't an issue,get some adjustable clamps made up,or fit offset spacers into the steering head and steepen up the front/reduce the trail.[/QUOTE]

Thanks for the suggestion, Death. Can you explain what offset spacers are and how they would work (remember I'm a technical illiterate)?

[kerryg]

It may sound obvious, but when people talk of dropping the forks in the yokes, they're only talking a few millimetres.
Lou


Thanks Lou. The consensus seems to be that its best to try raising the rear first (so as not to lose ground clearance) so I think that's the way I'll go.

[DEATH_INC.]

[QUOTE=kerryg]Thanks for the suggestion, Death. Can you explain what offset spacers are and how they would work (remember I'm a technical illiterate)?
They're a round spacer with an offset hole that you fit a smaller od steering head bearing into,you need to cut a slot into the steering head(where the bearing fits into)and have some blocks welded on and drilled/tapped so you can clamp the spacer.by moving the bearing back/forwards (with different offsets in the spacers) you change the rake.It's not the neatest solution(the bearings run off line a little,and you've gotta be careful to get them lined up (sideways),but it works.It changes the head pivot angle,where the offset/adjustable clamps only change the fork angle/trail.

[kerryg]

They're a round spacer with an offset hole that you fit a smaller od steering head bearing into,you need to cut a slot into the steering head(where the bearing fits into)and have some blocks welded on and drilled/tapped so you can clamp the spacer.by moving the bearing back/forwards (with different offsets in the spacers) you change the rake.It's not the neatest solution(the bearings run off line a little,and you've gotta be careful to get them lined up (sideways),but it works.It changes the head pivot angle,where the offset/adjustable clamps only change the fork angle/trail.

Thanks for explaining that, Death. I don't think I'm gonna try that though...sounds complicated :wacko: and I'm still figuring out how to inflate my tyres and where do I put the petrol in?.... :confused2

[F5 Dave]

A couple of simple fittings on the compressor & a petrol reservoir & we can pump those tyres full of petrol in ten seconds flat. :spudbooge

[kerryg]

[QUOTE=F5 Dave]A couple of simple fittings on the compressor & a petrol reservoir & we can pump those tyres full of petrol in ten seconds flat. :spudbooge[/QUOTEE


Even a simple goathurd (sic) knows that that's not right Dave....:msn-wink: