lumpy/understeering bike

Hi Everyone, been a guest to the site for years now, ride out with a couple of LB’s and read it almost daily (interesting/helpful topics - great work guys) but only just now decided to finally register. Will do a formal newbie intro soon, meanwhile can I just ask you for your opinion on my sickly-feeling bike. ZZR6 E9 (02), stock except 4 into 2 Blue Flame slip-ons. To the problem: riding back home last night (daily 16mls commute) I noticed a lumpy feel with bits of understeer, very similar to the low pressure/rear-puncture feel and immediately thought ‘not another flipping nail…’. Got home and tyre didn’t feel down, will check with gauge in the morning. 7am: bike feeling worse, lots of understeer + vibration, went to petr. stn to check pressure: all fine within 1psi… Only other noticeable problem was the rear breake sticking quite a bit to the disc (pads need replacing soon), with that nasty screeching noise when spinning the wheel on the centre stand. I might be stating the obvious here but, could a sticking breake be affecting the handling of the bike so much? Wheel alignment looks fine, and, sounds paranoid but the bike also feels ‘lower’ as in height (it’s already a very very low bike); could it be that the shock has gone, affecting the wheel? ‘Take it to your garage and get it checked’ I hear you say, yes but I just wanted to get a feel of where things might be wrong first if any of you’s had similar exp, as never a good idea to turn up clueless.
Cheers and safe ride everyone.

Welcome along (eventually):wink:

It’s hard to diagnose stuff like this online but here are a couple of ideas.

I cant remember if the ZZR has a centre stand, if it has (or using a paddock stand) get the rear wheel off the ground. Grab two diagonally opposed sides with your hands and try and push and pull the wheel towards and away from you to see if the wheel bearings are ok. There should be no movement.

If you are certain that the problem is coming from the rear end, the only other things to check is the shock and linkage.

The rear brake shouldnt really have an effect on the handling unless its binding really hard

Hope that helps:)

check yer headstock bearings too

Welcome to LB!

It could be something as simple as a tyre that’s wearing out and going square. When this happens it turns like a barge. When I put a new pair on my bike I nearly scare myself with how quick it drops in. How old is the tyre?

Thanks guys,

I do suspect too that it could be a bearings problem, will check both wheel/headstock and see what they’ve got to say…

Just annoying as since i serviced it + put the new exhausts on (2 weeks back) it was running like a dream. The cans transformed it in terms of smoothness, torque, idle and also MPG, not to mention a heart-warming rich but not loud sound (even though they’re not Evo).
Now though, they’ve started leaking (the cans) just as the old ones, at the connection with the downpipes. As they dont fit very tightly (motad downpipes being fairly larger diameter) I used exhaust bandage to build up the inside gap. This seems to work fine for a couple of weeks, after that they develop some play and the inevitable leak + horrible and loud noise + flat spots. Clamps are original though and don’t look very good so will try and get new ones.
Sorry don’t mean to pile up probs and bore you all up, it’s just that, coupled with the above, after a couple of weeks of a sweet riding bike it now runs like a complete dog… :frowning: I’ll roll up my sleeves and try to sort things out.

Keep up the good work!

Cheers

Thanks Jay,

tyre should be in not bad shape, got the Essential Rub boys to fit a new Diablo around early Dec, though I do clock up a few miles with commute + weekend rides. Doesn’t seem to have squared yet but yes, another thing to check closely this Sat morning.

Thanks for the advice.