CBR600FX - it's a bit mad !

[Gixer_fan]

I've been out a couple of runs on a 99 model CBR600 that I bought on a whim end of last year, and spent winter months recommissioning pretty much everything. I've a fair bit of experience with different bikes ( mostly 90s vintage - 600 and 1000), but I'm quite shocked at how lively this one is. Nothing power-wise until 8 or 9K then goes mental, takes off like a 2 stroke and the front wheel goes light, bars get twitchy, and the bike doesn't feel too stable. Anyone else ridden one of these ? Wondering if this is how they just are....

[Rubin215]

Eerrrmmm, it's a 20 year old 600; have you ridden a modern 1000...?

[Jazoli]

Rubin215 said:

Eerrrmmm, it's a 20 year old 600; have you ridden a modern 1000...?

To be fair the 2001 Hornet 600 I had was exactly the same, nothing, nothing, nothing, then all of its 85bhp in the last 3000 revs, peaky yes, mental no, it was fun when you were in the mood but a pain in the arse 95% of the time.

[Fckitdriveon]

I had an old old cbr600 on 96 N Reg iirc , that wasn’t sluggish coming from an rs125 it was always going to feel like a rocket ship.

But Having had a couple of the latest shape R1, they were genuinely hold on for dear life up in the Rev Range , never felt acceleration like it.

[shunter V8]

They were a very good bike back then but you did have to rev them or they were a bit flat.

[Rubin215]

Fckitdriveon said:

I had an old old cbr600 on 96 N Reg iirc , that wasn’t sluggish coming from an rs125 it was always going to feel like a rocket ship.

But Having had a couple of the latest shape R1, they were genuinely hold on for dear life up in the Rev Range , never felt acceleration like it.

My Hayabusa was pretty mental on acceleration (original '98, unrestricted, first one registered in the UK) but lots of recent kit would leave it for dead.
Launching it was pretty difficult despite its weight and length; even with (ahem) 15 stones of me over the front wheel it would lift the front on full throttle in first and second and would spin up without a moment's hesitation on damp roads.

The big advantage with modern kit is the electrickery that allows hamfisted bufoons to just dump the clutch and crack it wide.

[Fckitdriveon]

Rubin215 said:

Fckitdriveon said:

I had an old old cbr600 on 96 N Reg iirc , that wasn’t sluggish coming from an rs125 it was always going to feel like a rocket ship.

But Having had a couple of the latest shape R1, they were genuinely hold on for dear life up in the Rev Range , never felt acceleration like it.

My Hayabusa was pretty mental on acceleration (original '98, unrestricted, first one registered in the UK) but lots of recent kit would leave it for dead.
Launching it was pretty difficult despite its weight and length; even with (ahem) 15 stones of me over the front wheel it would lift the front on full throttle in first and second and would spin up without a moment's hesitation on damp roads.

The big advantage with modern kit is the electrickery that allows hamfisted bufoons to just dump the clutch and crack it wide.

I remember the subframe debarcle on the hayabusa, and the competition with the zx12r,

Always had a soft spot for a busa though, stupidly fast, comfortable, real marmite looks!

I never tried the launch on the R1, think I was too scared of binning it tbh!

I m without a bike currently but struggle to justify another 15k on a bike that d get ridden 2-3 times a year . Jealous of a mate sending me phots of a ride out today though! : (

[hebegb]

You must have a full on Chris Mayhew race prepped engine in there , cos a standard Cbr600fx ( great all rounder as they are ) couldn’t pull a sailor off your sister....
Something fishy going on methinks ....

[dibblecorse]

Mine felt like that, T57DHY was a great weapon, well that’s how it felt after my VFR400NC30 lol .... what else have you ridden???

[Gixer_fan]

It's not so much the acceleration or speed, sure it's tame compared to the 180+ hp bikes of today, it's more the bar shake you get when it gets on power. I had a 98 Fireblade, 996 Ducati which were pretty full on but this seems more twitchy. My old Gsxr1100 is a sofa compared to it. It's a very light bike. Maybe I've got her sitting to high at rear (too much preload) ? Maybe I just need to toughen up !

[orangefzr]

Gixer_fan said:

It's not so much the acceleration or speed, sure it's tame compared to the 180+ hp bikes of today, it's more the bar shake you get when it gets on power. I had a 98 Fireblade, 996 Ducati which were pretty full on but this seems more twitchy. My old Gsxr1100 is a sofa compared to it. It's a very light bike. Maybe I've got her sitting to high at rear (too much preload) ? Maybe I just need to toughen up !

It sounds to me like the head bearings could be either worn or could at least do with a clean re grease and readjustment.... As these bikes are not really as nervous as say an R6 on the throttle

[sc0tt]

Something sounds broken. Whilst they aren’t slow, they are pretty beige compared to other sports bikes.

Have you upgraded the powerband?

[Rubin215]

sc0tt said:

Something sounds broken. Whilst they aren’t slow, they are pretty beige compared to other sports bikes.

Have you upgraded the powerband?

Not always a good idea to upgrade the power band.
A 99 CBR will still be fitted with an old-style analogue powerband; modern digital powerbands are much more on/off compared to the volume control style analogue ones.

Mind you, that could be the OP's problem, especially if someone has fitted one from a different bike...

[Gixer_fan]

orangefzr said:

It sounds to me like the head bearings could be either worn or could at least do with a clean re grease and readjustment.... As these bikes are not really as nervous as say an R6 on the throttle

I replaced head bearings (amongst others) over winter. Tapered bearing type kit. Maybe I need to do check and torque them a little more. I didn't want to overload them.

Bike's in standard form and gearing (other than stainless downpipes and KN filter).
Not sure I need much more power, although I miss the mid range torque of a litre bike.
Actually best thing about it is it's not a pain to ride slow ..

[STe_rsv4]

Rubin215 said:

sc0tt said:

Something sounds broken. Whilst they aren’t slow, they are pretty beige compared to other sports bikes.

Have you upgraded the powerband?

Not always a good idea to upgrade the power band.
A 99 CBR will still be fitted with an old-style analogue powerband; modern digital powerbands are much more on/off compared to the volume control style analogue ones.

Mind you, that could be the OP's problem, especially if someone has fitted one from a different bike...

Depends which colour powerband you replace it with though surely?
Everyone on here is too quick to assume that replacing the powerband is some way of "instant power" when the reality is that you have to consider the colour to give you the hit that you need!

[Mr2Mike]

Gixer_fan said:

I replaced head bearings (amongst others) over winter. Tapered bearing type kit.

Tapered head bearings are a mistake IMO, even Honda gave up using them on the 954 as it made it too flighty. They are much harder to adjust correctly than the standard ball bearings as well.

[CAPP0]

STe_rsv4 said:

Rubin215 said:

sc0tt said:

Something sounds broken. Whilst they aren’t slow, they are pretty beige compared to other sports bikes.

Have you upgraded the powerband?

Not always a good idea to upgrade the power band.
A 99 CBR will still be fitted with an old-style analogue powerband; modern digital powerbands are much more on/off compared to the volume control style analogue ones.

Mind you, that could be the OP's problem, especially if someone has fitted one from a different bike...

Depends which colour powerband you replace it with though surely?
Everyone on here is too quick to assume that replacing the powerband is some way of "instant power" when the reality is that you have to consider the colour to give you the hit that you need!

It's not just the colour, be careful which thickness you fit. Those ultra-thin ones might look cool when you get them out of the box but they can really mess with a bike's performance.

[Gixer_fan]

Mr2Mike said:

Tapered head bearings are a mistake IMO, even Honda gave up using them on the 954 as it made it too flighty. They are much harder to adjust correctly than the standard ball bearings as well.

Oh dear, i thought they were preferable to ball, with more of a contact interface ? Interesting to know..

What's this powerband thing ? Is that to do with fueling or ignition advance ?

[Jazoli]

Gixer_fan said:

What's this powerband thing ? Is that to do with fueling or ignition advance ?

It's a windup, a hangover from school where you (didn't) fit different colour powerbands to your raleigh chopper or grifter.

[warch]

My bike was fitted with an anodised purple powerband by it's previous owner during the mid-90s.