Is it me or the bike? advice anybody?

[Black Knight]

Bit of history,

I bought my FZR 600 on ebay just before Christmas. Spent a few hundred on service, new rear tyre, fitting of a Breakers Maxton Shock. I also had another oil change and check over at a different garage a month later.

The bike just doesnt feel 'planted' I can almost feel it sway ever so slightly from side to side as i ride. If i go no hands it does swing over to the right.

I did have a little slip on it one icy morning doing no more than 10mph. broken indicator, cracked clutch cover and scratched pipe and fairings.

Ive done over 1000 miles this year and run it up to top speed, but i cant help feeling something is wrong elsewere. Could it be the front suspension? Its at 32000 so they feel a little spongy and could prob do with some attention.

This is the first time ive been on a bike really, bar a few months on a 400 a few years back. Is it me or do you think its worth investigating further?

[Zoffo]

Have you checked wheel alignment?

[stinkwheel]

I would check the usual:

1) Tyre pressures and tread depth.

2) Wheel alignment, especially the rear. Use a lath to check the wheels are both pointing in the same direction.

3) Wheel bearings (and cush drive bearing).

4) swingarm bearings.

5) Headstock bearings.

6) Binding brakes

Other factors:

The crash : You could have twisted the forks in the yokes, loosen the clamps and dunt the wheel square-on into a wall then retighten to square everything up. Worst case, the frame could be bent but unlikley in a low-speed getoff.

New shock: Could be set-up differently, if the ride height or preload are set too high, it will make the front end twitchy.

Work done on bike: Everything on the back-end has been messed with, check it is all done up tight. I assume your rear tyre matches the front? Some tyres (eg bridgestone BT45) go through a 'twitchy' patch after the first 100 miles or so.

Suspension: If the damping oil hasn't been changed for a while, it could feel a bit wishy-washy but this shouldn't really make it veer off to one side.

If it all checks out OK, I would probably blame it on the road surface or yourself, but your confidence should have taken a boost since you have checked everything out.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Black Knight]

Right,

I had a new back tyre recently, yes it does match the front, which is about half worn.

I checked the pressures. They were down about 5psi each. They are now correct.

I'll have a go at the wheel alignment tomorrow, not sure what a lath is though?

I think they checked all the bearings when it was serviced. The mechanic did seem to give it a really good going over, but then i wouldnt know if he wasnt

I did do some refresher training a few weeks back. The instructor was quite happy with me by the end of the session and couldnt fault my lines. He didnt mention that he noticed anything unusual. I really dont know if its me looking for something thats not there.

Thanks for the replies btw!

[Kickstart]

Hi

My FZR600 is quite stable. I like the handling of it

First suggestion would be to check that you have the right tyres fitted. If yours is a 1991~1993 bike (single headlight) then it uses a 4" rear rim with a 150/60 tyre. The only ones of these still available in a suitable speed rating are Bridgestone BT010 and BT014, neither of which are cheap.

After that check tyre pressures. Check the rear suspension linkages are all greased up and free to move. Check the rear shock really is suitable for your bike.

Steering head bearings are also possible. Same for wheel bearings (and the FZR has 3 bearings in the rear wheel plus another in the cush drive). Also check that the spacer is in place between the bearing in the cush drive and the ones in the wheel.

All the best

Keith
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[Mr.Everready]

If the tyre pressure isnt correct it can make a hell of a difference.
To check the wheels are straight get a piece of string, that'll give you a good idea if they're ok.
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the undemocratically unelected mod of the Scottish section

[G]

If nothing else shows up, how about getting a ride on another FZR, or at least another similar bike... and get the owner to have a ride on yours.

Sometimes I have convinced myself there is a problem with my track bike; when infact the problem is me worrying about the bike.

Obviously different bikes can have very different 'feel'; even different tyres can considerably change this 'feel'.

[Black Knight]

[Kickstart]

Hi

Just had a look on Dunlops web site and found nothing useful. They only give a fitment for the 1994/5 FZR600 (which had a 17" rear wheel).

Looked in the M&P catalogue and the only 130/70 tyre they list is T rated (ie, 119mph).

Can you check carefully what the tyre is that is fitted (size, model, speed rating, etc) and let us know?

All the best

Keith
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[loply]

Tire pressures?

My bike felt very similar to what you describe, turns out my rear wheel (which had a seized on valve, my excuse) was at 22psi, and my front at 24.

inflating to 28 and 32 sorted it instantly.
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[Kickstart]

Hi

Just found that the GPR70 and GPR80 are both also known as "Rideen". These are both only H rated tyres, suitable for up to 130mph (below the FZR600 top speed). Also they are not available in a 130/70 18 size, with the closest being a 140/60 18. Not sure how well that would work on a 3.5" rim.

All the best

Keith
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[Mr.Everready]

Should be "Sherlock" under your name not "Oracle" m8
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the undemocratically unelected mod of the Scottish section

[Kickstart]

[Gazdaman]

My bike feels very similar, probably due to a combination of knackered rear shock, VERY knackered rear wheel bearings, and a tyre that's past its best.

Pick 2.

Gaz

[stinkwheel]

[Black Knight]

Right, just checked the tyres.

Front
Dunlop Rideen GPR 70
110/70 R17

Rear
Dunlop Rideen GPR 80
140/60 R18

[Black Knight]

The Dunlop site shows these as the correct size but uses a tyre called Sportmax. I cant seem to find Rideen anywhere onthe site.

Keith??

[Black Knight]

I also found a wheel Balance bit on the garage floor. This must have some bearing. How much would incorrectly balanced tyres affect handling?

[Kickstart]

Hi

The GPR70 is stickier than the GPR80, so they are the right way round to give you better front end grip and reasonable tyre life (you have far more chance of catching a rear end slide).

The GPR70 and GPR80 are both H rated tyres, so a maximun of 130mph which is below the top speed of the FZR600. Not sure of the legal situation with this in the UK, but illegal in Germany for example.

A 140 is a slightly oversize tyre for the 3.5" rim, but still within reason. Unlikely to cause any problems.

As such I suspect the tyres are probably OK for general use, but don't go for any more top speed runs .

Use something long and straight to check the wheels are in line. I use an old scaffold pole. Hold it against the rear wheel and check how far to one side it passes on the front wheel. Then do the same on the other side of the rear wheel and ensure that the gap to the front wheel is even on both sides.

Rear wheel bearings are worth a check, especially that spacer. They are easy to loose, and tyre fitters do so sometimes. This results in a large sideways load on the sprocket carrier bearing and a fair amount of movement in the rear wheel (especially when the bearing collapses and wrecks the swinging arm).

Check the tyre pressures as mentioned above.

Check the steering head bearings. Check the swinging arm bearings and those in the linkage (linkage ones are probably OK if you have recently had them apart, presume you greased them up when you fitted the shock). Forks twisted in the yokes is possible. Fork seals could be worn.

An out of balance wheel will cause a bit of vibration. Often not that much of a problem really though. Worth checking that neither wheel is buckled and that both tyres are properly seated the whole way round.

All the best

Keith
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