Jerky on/off throttle control?

V

Varrus999

Well-known member
Forum Sponsor
Hi, I have owned an EX500 and Katana 600 in the past. Have lots of riding experience, so I don't think this is a rider issue. Am now on an 03 VFR, my first fuel injected bike. Am having a hard time controlling the throttle smoothly in low gear, low speed scenarios, like hair pins or 90 degree turns. There is a bit of lag in my throttle before it engages, and this causes the problem. Is this a cable adjustment issue? Is it a characteristic of fuel injected bikes? I read about a device called the G2 throttle tamer on the VFR forum I read...considering getting one but first I want to understand what the issue is...

Thanks for your feedback.
 
I spoke to a guy the other day with the same Gen VFR and me mentioned something about getting some mapping for his Power Commander to lesson the jerkiness.
 
This is something that I had issues with on my 1098. While researching this problem, my fix was to swap out the original throttle tube with a smaller diameter tube with less tolerance and it made all the difference.

I had purchased mine at Dan Kyle which is specific for Ducati.
 
Adjust the cables to how you like them.I hate slack in my throttle and find that every bike from the dealer that I've ridden has a good 1/4". It could just be the way the fuel injection is on that bike. My zx10 is the first year first gen and it has caught me off guard a few times and the powercommander helped but didn't completly get rid of it.
 
Varrus999 said:
Hi, I have owned an EX500 and Katana 600 in the past. Have lots of riding experience, so I don't think this is a rider issue. Am now on an 03 VFR, my first fuel injected bike. Am having a hard time controlling the throttle smoothly in low gear, low speed scenarios, like hair pins or 90 degree turns. There is a bit of lag in my throttle before it engages, and this causes the problem. Is this a cable adjustment issue? Is it a characteristic of fuel injected bikes? I read about a device called the G2 throttle tamer on the VFR forum I read...considering getting one but first I want to understand what the issue is..
Thanks for your feedback.
Click to expand...

This is a characteristic of all fuel injected bikes although it varies from bike to bike and is more pronounced on the ss bikes.
When downshifting through tight slower corners (ie at intersections) try staying in second gear rather than dropping to 1st gear.....this may reduce the on/off feeling of the fuel injection.
 
Dino Z said:
This is something that I had issues with on my 1098. While researching this problem, my fix was to swap out the original throttle tube with a smaller diameter tube with less tolerance and it made all the difference.
Click to expand...

What's a throttle tube?
 
Tighten up the cable, it should help with smoothing out the ramp up.
 
Dont know if I read your question right, but I will throw this out there. Maybe tighten your chain?
 
I just picked up my 06 VFR (same gen as yours) and this was really annoying for me at first! After putting 1500km on the bike since I've got it, I can say that my throttle jerkiness is smoooooooooth!

It's a learning curve for sure, this is my first fuel injected bike too! What I really hate though is how far the clutch lever grabs.. I wish it was cable and not hydraulic so I could adjust it where it grabs closer to the handle bar. Ugh.. can't wait for my knock-off adjustable pazzo levers to come in!
 
is this the bike with vtec? could that be kicking in?
 
dricked said:
Adjust the cables to how you like them.I hate slack in my throttle and find that every bike from the dealer that I've ridden has a good 1/4". It could just be the way the fuel injection is on that bike. My zx10 is the first year first gen and it has caught me off guard a few times and the powercommander helped but didn't completly get rid of it.
Click to expand...

That little bit of play in your throttle is so you don't accidentally throttle on, it's a safety thing.
 
cf1340 said:
This is a characteristic of all fuel injected bikes although it varies from bike to bike and is more pronounced on the ss bikes.
Click to expand...

None of the EFI bikes I've owned had issues like what the OP described.
 
Gummiente said:
None of the EFI bikes I've owned had issues like what the OP described.
Click to expand...

As I said it is more pronounced on ss bikes (supersport ) which are high horsepower bikes.
You ride a 55 hp harley-----the throttle action on harleys is mild .
 
cf1340 said:
As I said it is more pronounced on ss bikes (supersport ) which are high horsepower bikes.
You ride a 55 hp harley-----the throttle action on harleys is mild .
Click to expand...

Yeah, why did I know you'd assume all I've ever owned were Harleys... although my current ride is an HD with EFI, so was my '01 Triumph Tiger 955i and '99 Kawasaki Drifter 1500. Which, like the Harley, neither had EFI issues like what the OP described. And the Tiger was not a low horsepower bike by any stretch of the imagination.
 
fastar1 said:
What's a throttle tube?
Click to expand...

Well, the throttle tube is what controls your throttle on/off. The cables are attached to it and wrapped with your throttle grip.

In many cases, the the throttle tube is so sloppy that you can move it up and down with a 1/8" difference,that's alot.

The closer your tube is to your clip on the less jerky the response.
 
espro said:
That little bit of play in your throttle is so you don't accidentally throttle on, it's a safety thing.
Click to expand...

I put a 1/5 throttle in and have almost 0 slack (idle doesn't change when the bars are turned from lock to lock). If I fart hard enough the front wheel comes up.....just the way I like it. It's a personal prefrence but too much slack sucks when your trying to rev match.

Some bikes just have rough fuel injection, my buddys 09 r1 not jerkey, my 07gsxr 600 also not jerkey.
 
Last edited:
Varrus999 said:
Hi, I have owned an EX500 and Katana 600 in the past. Have lots of riding experience, so I don't think this is a rider issue. Am now on an 03 VFR, my first fuel injected bike. Am having a hard time controlling the throttle smoothly in low gear, low speed scenarios, like hair pins or 90 degree turns. There is a bit of lag in my throttle before it engages, and this causes the problem. Is this a cable adjustment issue? Is it a characteristic of fuel injected bikes? I read about a device called the G2 throttle tamer on the VFR forum I read...considering getting one but first I want to understand what the issue is...

Thanks for your feedback.
Click to expand...

Multiple things possibly at work here.

1. As others noted, make sure there is not excessive slack in the throttle cables. It should have a couple millimeters, no more.

2. Also as noted, make sure there is not excessive slack in the drive chain. Set it to specifications.

3. If the bike is a hi-miler, make sure the rubber cushions inside the rear wheel (between the sprocket hub and the wheel itself) are in good shape, because if they are chewed up, this could cause some extra driveline lash. Note that this should be filed under "extremely unlikely but possible".

4. That bike has a lot more power than your old ones did. There's a lot more power on tap. The throttle is gonna be more touchy, that's just the way it is. A good chunk of what you are feeling is highly likely to be "nature of the beast". If you think the VFR is touchy, don't try a '04 ZX10R with shortened gearing on it ...

5 and probably the real issue. Fuel-injected engines all have a feature called "deceleration fuel cut". It does exactly what it says. When you are coasting i.e. decelerating (throttle is open less than a certain very small amount, and the revs are above a certain amount) they cut off fuel delivery completely, largely for emission-control reasons. At some point ... i.e. you are starting to open the throttle, the fuel needs to come back on. When it does, the engine abruptly starts making power again. You feel that as a lurch, a step in power delivery. Different bikes do this to varying degrees. I haven't tried the VFR, but I have experienced that feeling on a '03 R6 and I found it to be extremely annoying, much more so than that of my ZX10R despite the ZX10R having a lot more power.

What to do about it ... also depends on the bike, because it depends on the specific fuel injection programming on each bike.

I have no idea what that "G2 throttle tamer" does, but it is likely a gizmo to change the decel fuel cut behaviour in some way.

Very careful mapping with a Power Commander can sometimes help, the idea is to drastically lean out the fuel delivery right at the point where the injectors come back on - involves a lot of trial and error to get it right! you have to set it up finely at each and every plausible engine speed - so that WHEN the injectors come back on, they inject very little fuel so that the engine makes less power at that point in time ...
 
I really appreciate all the feedback guys. Brian P, I especially like your post. I'm going to look at all these things from the simplest things first. I agree the bike is more powerful and I am very careful to 'feather' the clutch and throttle, with some success...but it really feels like an on/off thing. I don't like the slack in the cable and will try to tighen that up first - even if this is a more complex problem with fuel cutoff as Brian described I think I would prefer less slack in the cable...
Forum Sponsor
 
You must log in or register to reply here.
Back
Top Bottom