yzf750r 1993

[Manxman]

On entering slow/slowish corners, my YZF feels like it's trying to turn too quickly. That is, if going round a (say) left hand turn, it seems to want to turn more than I think it should and more than feels right. Once in the corner, it also wants to do a 'little', ie not huge - but noticeable wobble until the power comes on again going out of the corner.

On longer, quicker sweeping corners this isn't an issue and the bike is considerably more stable.

It has Pirelli Dragon Super Corsas (tread still legal). Not sure of the suspension setup.

Question is, is it:
1) me that needs to harden up;
2) the tyres; or
3) the suspension needs looking at?

It's just been through a major service, so no issues around straight frames, forks, etc

Any constructuve comments appreciated. Cheers.

[F5 Dave]

That's weird they can be a bit slow std.

How far are the forks dropped down? (how much showing above clamp?)

Check for spacers under the rear shock (need a torch, about 5mm is good).

I suspect mismatched or worn tyres, rear esp. Check pressures. Un-weight the front wheel (get a mate to balance on the stand perhaps) & kneel in front of front wheel & turn with hand. Any notchyness is steering bearings. Quite cheap use stds which are better than tapered rollers.

The forks on these are too soft for virtually any weight. Think I went to .85s for 75kg rider (can check the old box I saw at home the other day). Much betterer & I think my SP had stiffer springs than R model. They respond to compression & rebound kits well but they are a bit of coin.

Check this & also rear suspension is moving freely. If feels odd, sticky or squeeks take linkages off & inspect bearings/grease. Shocks that squeek are poo'd in the bore.

Set suspension to std for a starting point (internet will find settings or Exup brotherhood) people do crazy things to mess up so don't assume last owner knew what they were doing.

Then try again & describe if still having wobble, but need a better description before people start wibbling on about adding more rebound before we know the basis issues are attended to. In all honesty the rear shock will be well past its best by now.

[Manxman]

Thanks F5 Dave. I tend to agree that it is likely to be the tyres, because:
1) the front fork spring preload settings are at standard (just about to check the rebound settings)
2) the rear shock was rebuilt just over a year ago
3) I think there is a spacer on the rear susp, which looks as if it's 5mm
4) shouldn't be steering bearings (would have been picked up at the service)
5) the tyres are getting close to borderline

Agree that the last owner may not have made good tweaking decisions. He also did a couple of things he didn't let on about (like fecked front rotors...thanks mate), so it is possible he's stuffed something, but again that should've been picked up at service.

Excellent advice though, and much appreciated.

BTW, what tyres do you recommend for commute/touring?

[Robert Taylor]

On entering slow/slowish corners, my YZF feels like it's trying to turn too quickly. That is, if going round a (say) left hand turn, it seems to want to turn more than I think it should and more than feels right. Once in the corner, it also wants to do a 'little', ie not huge - but noticeable wobble until the power comes on again going out of the corner.

On longer, quicker sweeping corners this isn't an issue and the bike is considerably more stable.

It has Pirelli Dragon Super Corsas (tread still legal). Not sure of the suspension setup.

Question is, is it:
1) me that needs to harden up;
2) the tyres; or
3) the suspension needs looking at?

It's just been through a major service, so no issues around straight frames, forks, etc

Any constructuve comments appreciated. Cheers.

The rear shock tubes in these are not hard anodised and wear like crazy midstroke, meaning no damping midstroke. If the bike has done 15,000 ks or more this wear will be appreciable ( the body is throwaway ) and will be one of the contributory ( not neccessarily the main reason ) factors re steering imprecision

[F5 Dave]

The front rotors tend to do that. Some EBCs or Brembos off an Aprillia or Duc 916 etc will be a better bet. Don't waste money on cheapo discs.

I'd check the steering heads yourself as an easy thing to do in 2 min with the help of a mate to balance the bike. Yes 'Should' get picked up by service, but sometimes they get busy & mechanics are people too.

I've been running Michi pilot sports for last couple of runs, they make the bike steer real nice & while may be softer than you might choose for commuting they seem to last well & being 'year before last seasons' tyres are often discounted.

Check the comp settings (at bottom, erm I think all the R models had them) as well. But I'd really recommend the stiffer front springs as a cheap improvement. More so if you are heavier than me.

[Manxman]

...you know how there's supposed to be a rebound adjuster (looks like a screw notch)? Well, I can't seem to see where it is...any ideas

[Robert Taylor]

...you know how there's supposed to be a rebound adjuster (looks like a screw notch)? Well, I can't seem to see where it is...any ideas

Is it possible for you to forward images of the lower end of the shock? Its a long while since I have seen one of these, it may be a knurled finger wheel from memory.

[Manxman]

Is it possible for you to forward images of the lower end of the shock? Its a long while since I have seen one of these, it may be a knurled finger wheel from memory.

Here you go Robert. First pic is of lower end. Second is of the top, which is where I expected to find the rebound notch (based on the manual diagram (pic 3). Appreciate your time.

[F5 Dave]

Oh dear. It would appear the very early Rs didn't have the adjusters on the forks. There will be a blank boss near behind the front axle where the compression should live. See pic. Rebound is where the manual shows it & yours is blank. Mine is the SP, but I think later 'R's or other markets got the adjusters.
[edit]
Hold on, here's a pic with the rebound showing.

On the shock if fitted comp is a big knob on the reservoir & rebound a knurled collar at the bottom of the shock

[Manxman]

I've been running Michi pilot sports for last couple of runs, they make the bike steer real nice & while may be softer than you might choose for commuting they seem to last well & being 'year before last seasons' tyres are often discounted.

F5 Dave...had a pair of Michelin Pilots fitted today, and I have to say that these have made all the difference between being poor handling and consequent confidence, to like riding on rails and mucho fun again. Cheers for the advice.