Front suspension adjustment - explanation please

[BrotherPaul]

I have a ZZR600 and find that the front end "wanders" a little.

I suspect the that the suspension needs adjustment. I know how to do the preload adjustment on the front forks, however I don't understand whether the "hardest setting" is lighter steering and therefore contributing to the "wandering". Should I be making it harder or softer?

[Sumfun4me]

BP,

how many K's on the bike? have you just bought it, or had it for a while? Have you made any changes recently to the bike? I think you should start by checking the basics here (tyre pressures & steering head bearings) before going any further. As far as I am aware, the rebound or damping settings shouldn't affect the steering in regard to "wander" - other PSB members may like to chime in here, but I think this is more likely related to rake or trail.

[BrotherPaul]

Thanks SF4M, Bike recently purchased. Bike has 55K+km. 2004 model. New tyres and pressures are as per recommendations. Head bearings I don't know about. I don't understand the reference to rake or trail.

[shan]

There is a liksky here somewhere,
Hang about and i will rumage arround

[Sumfun4me]

Wandering is more of a geometry problem. It could be that the forks have been raised through the triples, or the rear ride height has been adjusted. To check your head bearings, pull the bike up on the side stand so that the front wheel is off the ground & turn the steering to opposite lock (RH). Let go of the steering & the forks should swing back to the LH lock. Pay attention to the stop - if it bounces, the head bearings are loose, if it travels real slow, the bearings are too tight (more likely the culprit for steering problems). Rake is the angle between the headstem & an imaginery 90 degree line (drawn through the centre of the axle and measured in degrees), and trail is the distance measured at ground level for the same thing - just google "motorcycle rake and trail" for a better explanation.

[agrid]

Swot up on static sag

[buelllord]

[QUOTE=Sumfun4me;2237686]BP,

steering head bearings ................................. trust me.

[Sumfun4me]

Agrid, whilst static sag certainly plays a role, I haven't ever encountered incorrect sag causing the steering to wander - I could be wrong, but feel it is more likely the steering head bearings are at fault, or there is a problem with geometry. Unfortunately I have found these areas to be the ones that second hand bikes have often been played with (usually when a mate suggests raising the fork height or the rear ride height for quicker turn in). Adjusting the sag is something that takes a lot more effort & knowledge, so it is often ignored. Then again, I have been known to be wrong once before.

[filbert]

doesn't really take much to upset the front end and make it wander, my DRZ400 wanders all over the road if i do the nuts up in the wrong order when i put the front wheel back on after changing dirt to road or vice versa.

bearings are probably the most likely but who put the wheel on after the new tyre was fitted? was everything tightened correctly?

[agrid]

Yeah I have had steering head bearings that were too tight and caused some wandering, but I figured the OP wanted to fiddle with his suspension and figured I'd suggest a starting point to determine if things were really messed up or not. Like Sumfun4me I remember that time I was wrong too, 1987 I think it was.

[Desmo]

Worn head stem bearings also cause wandering.

[Scoundrel]

Paul, have you already fiddled with the fork settings? Doubtful the steering head bearings are the culprit, easy enough to check though.

What PSI are you running in the front tyre?

[jules_1972]

[QUOTE=buelllord;2237759]

BP,

steering head bearings ................................. trust me.

^^^ whs ^^^

[BrotherPaul]

Hi Scoundrel, am running 36 front and 41 rear as per the owners manual. No, I haven't done anything to the settings and I would seriously doubt that the previous owner (who purchased it new) would have done anything either. He is an older guy (80 y/o) that I have known for a while and he indicated that apart from servicing/tyres/replace battery etc he had done nothing to the bike since new.

Thanks to others also for input. I'll check the head bearings as suggested.

[Bendito]

Also, how worn is the tyre?

[Scoundrel]

Hi Scoundrel, am running 36 front and 41 rear as per the owners manual. No, I haven't done anything to the settings and I would seriously doubt that the previous owner (who purchased it new) would have done anything either. He is an older guy (80 y/o) that I have known for a while and he indicated that apart from servicing/tyres/replace battery etc he had done nothing to the bike since new.

Thanks to others also for input. I'll check the head bearings as suggested.

Yeah those owners manual suggestions for tyre pressures are retarded, try backing the pressures off to say 32 and 34 and see if it makes a difference. Also, a shitty front tyre (or if the front wheel is out of balance) will cause you problems. I had a 'wandering' feeling like you ages ago and blamed the head bearings but the tyre was the culprit (and yes in hindsight it really was rooted the guy at the bike shop gave me a serve for riding on it)

The ZZR front end is hardly going to be the example of suspension and steering excellence but like a lot of bikes one thing I have noticed is that the right tyre can make a world of difference.

[BrotherPaul]

Also, how worn is the tyre?

Almost brand new

[BrotherPaul]

Yeah those owners manual suggestions for tyre pressures are retarded, try backing the pressures off to say 32 and 34 and see if it makes a difference. Also, a shitty front tyre (or if the front wheel is out of balance) will cause you problems. I had a 'wandering' feeling like you ages ago and blamed the head bearings but the tyre was the culprit (and yes in hindsight it really was rooted the guy at the bike shop gave me a serve for riding on it)

The ZZR front end is hardly going to be the example of suspension and steering excellence but like a lot of bikes one thing I have noticed is that the right tyre can make a world of difference.

OK, I'll back off the tyre pressure a bit and see how it goes. Maybe it is just how it is with these bikes. Spoke with my brother, he has a ZZR1100, and he says that his is similar.

[Scoundrel]

OK, I'll back off the tyre pressure a bit and see how it goes. Maybe it is just how it is with these bikes. Spoke with my brother, he has a ZZR1100, and he says that his is similar.

Before you do, just do a check on the head bearings. Put it on the centre stand, and get a car jack and place it under the belly pan where the opening is (there is a hard plate that is welded to the headers from memory) and gently jack it up until the front wheel is off the ground. Now there will be no load on the front end and you can turn it from letf to right freely. There should not be any binding or resistance and if there is you have a problem. Similarly, there should not be any fore-aft and side to side movement of the steering head. Or up and down movement for that matter.

[BrotherPaul]

Before you do, just do a check on the head bearings. Put it on the centre stand, and get a car jack and place it under the belly pan where the opening is (there is a hard plate that is welded to the headers from memory) and gently jack it up until the front wheel is off the ground. Now there will be no load on the front end and you can turn it from letf to right freely. There should not be any binding or resistance and if there is you have a problem. Similarly, there should not be any fore-aft and side to side movement of the steering head. Or up and down movement for that matter.

OK, I did this and there was no movement as you described. Movement from right to left was smooth.

I'm going for a ride tomorrow so will report back on handling with altered tyre pressures. I will let my brother have a ride (he is a much more experienced rider) and see what he thinks about the handling. Thanks heaps for your help.