Ferocity of first

[Jim Mc]

I've been using my Honda CBR600rr heavily over the past month for commuting, whereas in the past i'd only use it on the weekends with nice open roads. While I'd kind of noticed this issue, it's never really been a problem in the past.

Now though I'm filtering a lot more, covering a ton of slow riding at junctions and roundabouts and I'm having a real issue with first gear. It's really fierce, it's more noticable on hill starts because there's more drag so you need a touch more throttle, but if I'm doing a hill start on a junction, there's a finite point which will give me a smooth pull away, a fraction less throttle results in a stall, a fraction too much and the bike tries to rip my arms out of their sockets and jolts me back as I pull away.

So I'm slipping the clutch, but that's pretty precise as well, if I let it out too quickly I get the whiplash effect, if I hold it too long I pull away too slowly and feel like I'm in slow motion. It all feels a bit too finite and finnicky.

How can I sort this without affecting the overall performance of the bike? Would a power commander fix this?

[MarJay]

[garth]

It's a revvy IL4 600 with a tall 1st gear.

I wouldn't expect it to try and rip your arms off without a fuckload of revs.
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You ain't a has been if you never was

[Kickstart]

Hi

Some Hondas were renowned for lousy low down fueling.

However I would be tempted to suggest the first thing to do would be to balance the throttle bodies.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Jim Mc]

It's an FI 2007, can the TB's still be balanced on these? The choke is automatic so I'd expect the valve on the TB would be automatic too?

If I drop the front gearing how will that affect the revs/economy? Higher top speed, lower accel due to more torque required? Will this stress the gearbox/wear the engine?

[Kickstart]

Hi

I would expect them to still be able to be balanced. Need to to this so each one is synced. The choke is just a crude system to richen the mixture and possibly also allow a small amount of air to bypass the throttle bodies.

Having another thought. I presume there is a throttle position sensor on the throttle bodies. If this were set wrongly then at small throttle openings the ECU might not get a signal, hence no extra fuel when the throttle is first opened gently.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Jim Mc]

Cheers Keith, its given me a few points to take a look at.

Does anyone know if the haynes manual for the -2006 model is suitable for the 2007-onwards model cbr? Haynes don't seem to produce a manual for this bike.

[DrDonnyBrago]

My 2001 CBR has a snatchy 1st gear and rather poor low down fuelling, you work around it easily enough, I tend to use 2nd with a bit of clutch at slow speeds as it is smoother than 1st (1st for pulling away of course). Pulling away requires a decent amount of revs and feathering the clutch in, without intending to cause offence it just sounds like you have rather poor clutch control and are blaming the bike, the more you ride it the better you will become.


It is a long gear and a 600 motor with not a lot happening low down, if you are not far from stalling when pulling away then you aren't revving it high enough - try more revs and slipping the clutch for longer.

[evoboy]

The CBR600F has a lower first gear so doesnt really suffer from that problem.

The 600RR has a very tall first gear. Check your throttle play at the twsit grip, should be minimal on these ( even though they come out of the crate with 'fuck loads' (<technical term) of play, they ride much nicer with minmal amount.

Also check your chain tension is correct and the final drive is in good condition.

Other than that, unfortunatly youll have to live with the lack of oomph in first. It was never built for town work and is only really happy above 8k rpms.

Altho, i never found it an issue around town....
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Suzuki GT250 x7------- Fazer 600------CB250RS------Aprilia Rally 70----- Bandit 600

APT Motorcycles

[DrDonnyBrago]

EDIT: Some misinformation

[Kickstart]

Hi

Not quite the whole story. Comparing 2006 F and RR models, the RR has a higher first gear ratio and a higher final drive ratio, but a lower primary drive ratio. Overall gearing in first gear is very similar.

34/12 on your bike is actually shorter gearing than 33/12

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[robbieguy2003]

I've had two, and now have the RR7 which I think is the same as yours. All things being even and the bike being mechanically sound and setup it should be fine.

If i'm pulling away from lights i'll tend to rev to about 4K then bring the clutch out in a slowish manner while gradually feeding in more throttle.

For a 600 supersport the midrange isn't poor to be honest, it can be ridden from 3K up and not totally suck, it does still pull.

It might be that you've been used to weekend blats with less stop and start traffic, so your highspeed control will be good but the low speed stuff will suffer. I used both of mine to commute on and found them fine but now I commute less, i've found my slow speed work has got worse, so practice might fix it. They're not the easiest bike to ride slowly.
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Current Bikes: Honda CBR 600RR - '07, Suzuki GSX1250 FA ST '11
Old Bikes: Suzuki Intruder 125 LC - '2001, Honda CBR 600F - '92, Honda CBR 600RR - '03

[DrDonnyBrago]

[Kickstart]

Hi

I agree the gearing is lower on the RR, but down to the primary drive ratio rather than the actual first gear.

Comparing a couple of dyno runs online for the F and RR, looks like the RR actually has more torque once past 3k (and the graphs started properly at about that, so anything below is pretty meaningless).