How I eliminated the twitchy throttle

[Joaoduarte]

7 hours ago, Dennis.Halmstad said:

Maybe its still to expensive to make it right on production bikes?

If twitchiness was thing on MotoGP bikes they would probably crash a lot more.

I don't think the technicians tell the worlds best riders "If you never completely close the throttle...." 

Thats true, but mt07 is for masses not for motogp riders.

[Triple Jim]

The way the fuel injection reacts to a twist of the grip is completely configurable without adding cost, so I suspect Yamaha made it the way it is to make it respond the way they think will sell the most motorcycles.  "Twitchy" makes the engine seem very powerful.  A small twist and you get big power.  Imagine if they had made it so that it took a lot of twisting for a normal takeoff.  All the reviews would have said something like "the engine response at low throttle settings is sluggish".

It's similar to the way guitar amplifier manufacturers often make the volume control so that it's loud at "1" or "2" on the dial.  If there were two amplifiers side by side and one was that way and the other one had to be set at "6" to start to be loud, many users would think the first amp was much more powerful.  I've even seen guys with two similar amps compare them by what the dial is pointed to for a given loudness, rather than how loud they get before they get into distortion.

Edited April 9, 2021 by Triple Jim

[Nealsmo]

That's why my amp was custom built to go to 11.

[Loch]

On 4/7/2021 at 11:08 PM, D.A. said:

••• Modified R6 tube •••

Is this the final iteration? I want to try this mod with mine, I got the Motion Pro throttle tube that’s between the R6 tube and stock tube sizing. I went back to the stock tube because the larger pulley just magnified the twitchy on/off fueling at low rpm/speeds. Do you have instructions or measurements of where you drilled the hole and cut the eccentric into the cam? If not I’ll just go by your photo if that’s what you’ve been running and if you think it smooths out the 0-10% throttle 

[Pursuvant]

5 hours ago, Loch said:

Do you have instructions 

Do yourself a favor, don't mod the R6 tube first. Mod your stock tube for practice, and test your tools for the job.

Here is step by step, on the stock tube here

Don't cut far around the tube. Cut only the closed to small throttle opening. Your only trying to smooth first 3% of twist, then go hot. Especially when you are ready to do R6, I did a different grind, it's smoothed about 3% then I went nearly instantly to full hot R6, so I'm smooth at walking in parking lot but still loft the wheel with just some twist.

PM me b4 u do R6, I'll help

[Loch]

On 4/9/2021 at 7:46 PM, Pursuvant said:

Do yourself a favor, don't mod the R6 tube first. Mod your stock tube for practice, and test your tools for the job.

As it sits right now, I prefer the stock tube to the aftermarket one. So if I mess up one of the tubes attempting this I would rather it was the r6 tube because I would go back to running the stock tube. Perception of how much I’m twisting my wrist doesn’t make the bike feel faster or slower, and after riding my bike with the r6 tube back to back with my friends stock machine I actually prefer his foot throttle control. I think if I did it correctly and smooth out the first 3%, I’d probably take the r6 tube, but I kind of like the fine tuning adjustment of the oem one now. Maybe an ecu flash is what I really need more than a throttle tamer, maybe both

[D.A.]

On 4/9/2021 at 4:44 PM, Loch said:

Is this the final iteration?

On 12/4/2020 at 6:41 AM, robbo10 said:

As you taking it apart, I wonder whether you might: cut a piece of card to show the profile you have cut; and some references like the profile of the ouside of the flange, and positions of the holes.

In response to @Loch and @robbo10:

Below is a link to a template of the latest version of the customized R6 cam profile. It's a PDF file. It's formatted as a standard 8-1/2"  x  11" document. Print it out and it will be to scale.

This forum doesn't allow the upload of PDF files so the file is on GoogleDrive:

https://drive.google.com/file/d/1IEazqG4YaP7WcdEu30VceCA_Feuqo8nf/view?usp=drivesdk

Here's a JPG of it for reference and so the image will display on this site. Don't use the following image for printing or as a template, though, because it won’t be to scale. Use the PDF linked above.

 

 

Edited May 28, 2021 by D.A.

[Pursuvant]

12 minutes ago, D.A. said:

In response to @Loch and @robbo10:

Below is a link to a template of the latest version of the customized R6 cam profile. It's a PDF file. It's formatted as a standard 8-1/2"  x  11" document. Print it out and it will be to scale.

This forum doesn't allow the upload of PDF files so the file is on GoogleDrive:

https://drive.google.com/file/d/1IEazqG4YaP7WcdEu30VceCA_Feuqo8nf/view?usp=drivesdk

Here's a JPG of it for reference and so the image will display on this site. Don't use the following image for printing or as a template, though. Use the PDF linked above.

 

 

Brilliant work around ! PDF file is perfect to scale, that is just fantastic, thank you

[D.A.]

 

On 4/9/2021 at 4:44 PM, Loch said:

...Do you have instructions or measurements...

And to go along with the template I posted a few minutes ago, here are some notes regarding the installation process:

You can, of course, remove the entire rubber grip from the tube if you prefer!

To reduce twitchiness to less than what you get with a stock FZ/MT-07 throttle cam (which is 5mm as illustrated below), you need to shave the cam down to less than 5mm. I shaved my R6 cam down to 3mm but then cut a groove that further decreases it to 1.5mm:

 

Use a 1/4" drill bit to make the new hole:

 

But before drilling, flatten the end of the cam to eliminate the ridge. This makes drilling the hole much easier:

 

 

Note that when I started cutting into my R6 cam, I discovered it is partially hollow inside:

 

 

Edited April 16, 2021 by D.A.

[Loch]

31 minutes ago, D.A. said:

Below is a link to a template of the latest version of the customized R6 cam profile. It's a PDF file. It's formatted as a standard 8-1/2"  x  11" document. Print it out and it will be to scale.

This is some quality content, gonna try it out next week! Picking up another toy this weekend so there's a strong possibility of that that taking over my very small attention span for the foreseeable future

[br4nd0n]

Why is the stock second hole oval?

[D.A.]

2 hours ago, br4nd0n said:

Why is the stock second hole oval?

Rather than envisioning it as being oval, think of it as having a shoe-like shape. The opening where the deceleration cable slides in is biased toward the heel of the shoe while the cylinder on the end of that cable crams into the toe. 


 

All of the grips I’ve examined have the same configuration:

• Acceleration cable hole = round

• Deceleration cable hole = oblong

Why do they make it that way? Because when you’re at full throttle, the extra-long “fangs” keep the decel cable from detaching from the cam.

The visuals below illustrate the way the path of the decel cable changes when the throttle is twisted. When closed, the cable hugs the cam wheel and no fangs are needed but when at full throttle the cable pulls away from the cam and needs the fangs to stop it from detaching:

The hole for the acceleration cable doesn’t need extra-long fangs because it never gets pulled away from the cam. It starts out wrapped on the cam and wraps around it even more when you twist the throttle.

Edited May 8, 2021 by D.A.

[br4nd0n]

Thanks for that visual description. I still think it's odd to have it larger than the size it needs to be. It seems like it gives more of a chance to fall out and requires the "fangs" to be more prominent instead of just making the hole diameter wide enough to slip in from the side only.

 

Question:

Everyone seems to be talking about taming the twitchy throttle on the acceleration side, but what about that slow speed 15mph and below where you want to be able to let off the throttle without it suddenly giving you all of that engine braking?

I find my self tank slapping my nuts more often on the slow speed decel than having issues on accel. It's caused me to slip the clutch a ton when I'm in those slows situations.

Edited May 8, 2021 by br4nd0n

[Loch]

1 hour ago, br4nd0n said:

but what about that slow speed 15mph and below where you want to be able to let off the throttle without it suddenly giving you all of that engine braking?

Ecu flash to disable injector cutoff on deceleration. Will help smooth out the acceleration twitch as well, this mod is in addition to or adjacent to that