Jerky throttle problem

[325rocket]

hey guys and girls,

Ive recently upgraded from a GT250R to a CBR600RR and im having real problems getting used to the jerky throttle that seems to be a by product of fuel injection. I just cant find the correct gear to be in going around corners. on the 250 i could roll off hit the corner then roll back on but with the 600 when i roll off the bike almost stops. Then when i roll back on i go through a really awkward jolty weird scenario that makes any rider within half a km back off in case i bin it.
could this be something to do with the emission regs these bikes have to meet or is it just how it is?

[discotex]

Will take a little while to get used to the engine braking and throttle of a 600. The CBR FI is really good so it's probably more that the GT250R let you be quite hamfisted with the throttle.

Got two drills that might help.

1. Sit on the bike and open the throttle enough that it just comes off idle - i.e. barely moves on the tacho. Do that over and over. Practice at the lights etc. That's how much you should be on the throttle through the apex.

2. On straight road rev up to say 10k RPM then roll off the gas. Once you get down to 30km/h roll it open again. Try in 1st and 2nd gear. Also try to catch the speed as you're coming down. Say pick 42km/h and try crack the throttle just enough that you catch 42km/h exactly.

The other thing is you might be letting the revs get too low in the middle of the corner before you crack open the gas because you're not used to the higher RPM of an IL4.

[hayd3n]

prahaps you have a blocked fuel filter??

[325rocket]

Will take a little while to get used to the engine braking and throttle of a 600. The CBR FI is really good so it's probably more that the GT250R let you be quite hamfisted with the throttle.

Got two drills that might help.

1. Sit on the bike and open the throttle enough that it just comes off idle - i.e. barely moves on the tacho. Do that over and over. Practice at the lights etc. That's how much you should be on the throttle through the apex.

2. On straight road rev up to say 10k RPM then roll off the gas. Once you get down to 30km/h roll it open again. Try in 1st and 2nd gear. Also try to catch the speed as you're coming down. Say pick 42km/h and try crack the throttle just enough that you catch 42km/h exactly.

The other thing is you might be letting the revs get too low in the middle of the corner before you crack open the gas because you're not used to the higher RPM of an IL4.

cheers for the reply.

yep that all makes sense.
and your rite, im really not used to high RPM. i feel like im going to kill the thing when it goes over 9000rpm haha.
So what sort of RPM should i be cornering at?

[325rocket]

prahaps you have a blocked fuel filter??

could be but i think its more a problem with me not the bike. ill check it though

[klyong82]

It is common and I presume you will get used to it after you ride it more. I have it on my CBR1000 too...man you must be loving the power moving from a 250 to 600.

[naphazoline]

i have a similar issue with the 06 blade.from closed to opening the throttle,it's got quite a bit of snatch.i'm finding it a bit difficult to catch my desired speed without feeling any snatch.i've read in a review that it's a honda fuel injection issue.
i done a bit of searching on different forum threads and other net stuff,and found a couple of possible solutions.

1:slip the clutch a bit for the real slow corners.

2:get a suitable professional to make a custom fuel map.apparently,this will make a smoother throttle response over the factory fuel mappings.

3:using a power commander is supposed to make a good difference.

can't say i've got 2 or 3 done, but that's what i'm looking at doing next year some time.

for now,i'm just living with it.

[hayd3n]

yeah the power change is incredible hard to keep in the speed limit at start
i was so used to hitting 50 ks in first on my vtr and then i got the yzf lol

[JimO]

yeah the power change is incredible hard to keep in the speed limit at start
i was so used to hitting 50 ks in first on my vtr and then i got the yzf lol

you told me you only rode it to church on sundays:yes:

[hayd3n]

you told me you only rode it to church on sundays:yes:

well um and on mondays and tuesdays and wednesday and thurdays and fridays and saturdays
when u want the wee booklet?? i have 2 now lol

[KelvinAng]

Welcome to Honda inline4 :-)

[discotex]

cheers for the reply.

yep that all makes sense.
and your rite, im really not used to high RPM. i feel like im going to kill the thing when it goes over 9000rpm haha.
So what sort of RPM should i be cornering at?

No worries. 9000rpm is where the power really starts! Find some straight back road, pop her in 2nd and open it wide until you get to the redline. Just be prepared to change your undies :lol: - Don't try it in first without the rear brake covered as you'll have the wheel in the air when you hit 10-11k.

For easy pace open road riding you want to be cornering in second between 50 and 80km/h. I tend to stay in second a lot. Remember this bike does well over 100km/h in first gear....

Real tight twisties can be a pain when you're sorta between first and second. Gets easier when your throttle control gets more precise.

Unless you're in license losing territory or are just cruising on straights you shouldn't ever need to get out of third.

[discotex]

It is common and I presume you will get used to it after you ride it more. I have it on my CBR1000 too...man you must be loving the power moving from a 250 to 600.


i have a similar issue with the 06 blade.from closed to opening the throttle,it's got quite a bit of snatch.

It's been the same for all the 600's I've test ridden. Under about 4000rpm the FI says "fuck off I'm not meant to rev this slow".

A loose chain magnifies the effect but I don't think 325 has enough km on the bike for that to be an issue yet.

[vifferman]

Two things:
1. Take out all the slack from the throttle cable.
2. Set the idle revs highish (it's 1300 rpm on my VFR, 200 higher than recommended).
3. Get used to slipping the clutch for slow speed manouevres, and for things like u-turns, use the back brake as well, so you're balancing the throttle and brake against one another.
4. Disable the "closed loop" mode of the EFI*, by disconnecting the oxygen sensor(s) and fitting the appropriate resistor(s). (It's 330ohm on the VFR, but the CBR could be different).
5. You could fit a Power Commander as well if this doesn't help, but see how you go.
6. Make sure the chain is always clean and properly adjusted (this is the most minor of points, but it all helps).

*Some of the jerkiness is the brief hesitation when the EFI switches modes from "closed loop" to mapped mode. [This is assuming the 600 has "closed loop" mode and O2 sensors like the VFR does]

[imdying]

In a month from now you'll have forgotten all about it :yes:

But yeah, check the throttle cable slack... Honda always sell them with arseloads for some reason.

[discotex]

*Some of the jerkiness is the brief hesitation when the EFI switches modes from "closed loop" to mapped mode. [This is assuming the 600 has "closed loop" mode and O2 sensors like the VFR does]

I'm guessing you mean PAIR? 600rr.net has good info on how to disable it if you can be bothered. I haven't found a need to though.

[vifferman]

I'm guessing you mean PAIR? 600rr.net has good info on how to disable it if you can be bothered. I haven't found a need to though.
Nope.
The PAIR is summat else. Tried disabling that - it dropped the idle heaps, and made a bit of a hole in the power delivery at low-mid range.
My "helpful" comments were made on the basis that I assumed the CBR had a similar EFI system to the VFR, which has a dangerous hesitation when you throttle off (say, for a slow-speed corner) then throttle on again. This is mostly caused by the "closed loop" mode, which is used when the engine is running under constant lowish revs, or small throttle openings, when it uses the information derived from the various sensors including the oxygen sensors in the exhausts, to decide how much fuel to squirt in. When you open the throttle, it switches to 'mapped' mode, which uses the TPS sensor and MAP sensor (and a couple of others) to work out which setting on the EFI maps to use. The transition from closed loop to mapped mode takes a brief time, which is too long.
But (however!) for many bikes, EFI is much more 'lightswitch' (on/off) than carbs are, and does take some getting used to, regardless of whether the EFI system is mental or not.

Personally, I test rode a CBR600 before/after riding my VFR, and found the throttle response was OK, so I'd guess that most of the "jerky throttle problem" alluded to is just part of the learning curve for switching from a carbed 250 (with somewhat laggy response) to the more instantaneous response of a modern EFI'd 600 sports machine.

[325rocket]

The transition from closed loop to mapped mode takes a brief time, which is too long.
But (however!) for many bikes, EFI is much more 'lightswitch' (on/off) than carbs are, and does take some getting used to, regardless of whether the EFI system is mental or not.

Personally, I test rode a CBR600 before/after riding my VFR, and found the throttle response was OK, so I'd guess that most of the "jerky throttle problem" alluded to is just part of the learning curve for switching from a carbed 250 (with somewhat laggy response) to the more instantaneous response of a modern EFI'd 600 sports machine.

i had a feeling it was the closed loop - mapped transition. i guess i will get used to it in time.
thanks for the replies

[vifferman]

i had a feeling it was the closed loop - mapped transition. i guess i will get used to it in time.
thanks for the replies
You should at least get the throttle cable slack taken out. The manual says it's supposed to be there, but it adds to the hesitation somewhat.
The best thing to do is ride, ride, ride! Go and practice some slowish speed turns, etc., using the back brake as a rudder, and when you're in slow or start/stop traffic or otherwise going slow, make a point of using the clutch rather than the throttle to regulate your speed. You'll see what I mean when you try it.

[discotex]

Nope.
The PAIR is summat else. Tried disabling that - it dropped the idle heaps, and made a bit of a hole in the power delivery at low-mid range.

Ahh right. Quite a complex fueling system. I haven't read through the service manual properly yet to get my head around it all.

[slimjim]

mate its a totally new ride..and you'll find things hugely different forsure..and won't touch your cable just yet...would say getting use to it been the first thing...an ya's worries will go..and don't roll off completely...enjoy the bigger grunt..

[captain_andrey]

Had the same problem with I first got the 600. But it all went away as I got more precise with the throttle. On a 250 the margin for error was huge so I never learned to roll on the throttle smoothly.
What I do is make sure I am in 2nd, put some pressure on the rear break and slip the clutch when I need to go real slow.
So just go riding, you will pick it up real fast.
After completing the 1000k cruise on saturday, I finally feel at one with the bike. 30k of gravel really helped with the confidence, esp once I got up to 100km/h on the loose stuff.