Schooled On Throttle Control

[Hotfoot]

I recently got a nice reminder of the importance of good throttle control.

 

I had a race practice day last weekend, and although my bike SEEMED to run fine, when I got out on the track I discovered a problem. I'd lean the bike over into a corner, then when I tried to roll on the gas the bike would sputter and surge - presumably due to a problem in the carb. Since I was hoping it would resolve itself after running a session or two with fresh gas (getting to the carb not easy on this machine), and it wasn't doing it in every corner, I decided to keep riding, and of course I was trying to run a pace close to my normal race pace.

 

In 3 or 4 of the corners, I'd get to my turn point, enter at my normal speed (which often meant passing a larger heavier bike on the inside) then start my roll-on. The bike would hesitate, which was overloading the front and making it want to run wide, then surge forward, overloading the back tire, then sputter and hestitate again and overload the front. Holy cow! I was sliding the tires, rocking the suspension back and forth, and just generally trying to manage a very upset and unstable machine! I had to slow down significantly, and stop passing the big bikes in those corners, because at my normal pace I was really concerned I'd fall down or run off!

 

I came to CSS as a student with very little riding experience (and no track experience) so I learned about good throttle control on day one, and never did a lot of rolling on-off the throttle mid-corner. Boy, was this a lesson for me! My bike had its own poor throttle control that day and I learned quite a bit about the bad effects of going on and off the gas in a turn. My suspension, which is nicely set up for me, suddenly seemed like an enemy and my super grippy race tires were sliding unexpectedly - front AND back - and ALL of my $10 of attention was abruptly shifted to the bike itself, and trying to manage the instability of it. I got a whole new perspective on throttle control!

 

The carb is getting cleaned and checked this week - going to give it another try this weekend.

[ktk_ace]

Its good to have a nice , smooth and reliable carburator imho.

 

I saw the effects of a not so smooth throttle application in the exit radius of a downhill hairpin turn just 2 days ago too :

 

the result was new rider scrapped his bike's centerstand (chopping the throttle due to SR kicking in) and lowsided right in front of me; i righted my bike and stopped 2 feet away from him ...

[Lnewqban]

..........I came to CSS as a student with very little riding experience (and no track experience) so I learned about good throttle control on day one, and never did a lot of rolling on-off the throttle mid-corner. Boy, was this a lesson for me! ...........and ALL of my $10 of attention was abruptly shifted to the bike itself, and trying to manage the instability of it. I got a whole new perspective on throttle control!

 

Priceless post!

[Aufzynder]

Yeah, as I read your post I rembered a Situation that happend to me some years ago.

 

A Buddy had a new bike an we made a tour. Right after the tour I rode his bike. It was a Kawasake GPZ 600, power reduced to 34 horsepower (due to local law) by a reduction in the carb. At 6-7k rpm there was a great performance-hole... Awful riding... and dangerous.

 

In mid corner at full lean I ran right into this performance hole, the engine stuttered (I know no better word in english) like as I ran into the limiter and I lost both the front and rear tyre. Only god knows how I managed to stay on that sliding bike...

[ktk_ace]

Yeah, as I read your post I rembered a Situation that happend to me some years ago.

 

A Buddy had a new bike an we made a tour. Right after the tour I rode his bike. It was a Kawasake GPZ 600, power reduced to 34 horsepower (due to local law) by a reduction in the carb. At 6-7k rpm there was a great performance-hole... Awful riding... and dangerous.

 

In mid corner at full lean I ran right into this performance hole, the engine stuttered (I know no better word in english) like as I ran into the limiter and I lost both the front and rear tyre. Only god knows how I managed to stay on that sliding bike...

 

Im guesstimating you hit the CDI rev limit and it started to retard the ignition to bring the engine revs down...

 

I know of 2 systems, one is skipping 1 ignition per 2 ignition cycles and the other , which you described... skipping all ignition until the revs go down.

 

As you are in the corner, the smaller radius of the outer tire coupled with the chain pulling the engine and skipped ignition cycles ... it makes for a nasty combo

 

Its like engine braking right in the middle of the turn

[ScrmnDuc]

I'm glad you came out unscathed.

What is the value of the lesson learned?

How can you apply this in your coaching?

[Hotfoot]

Hm, good questions.

 

Lessons learned:

1) You can't go very fast without good throttle control

2) I realized it is a lot easier to slide the tires with abrupt throttle actions than I thought - BOTH front and back.

3) You can break the rear tire loose with a lot less throttle than I thought - IF you slam it on very suddenly

4) Lack of control over the bike immediately captures ALL of your attention

 

I knew all the reasons why good throttle control is important and all the ways poor throttle control can cause problems, but being forced to experience those poor results made it more real to me how easily you can crash if you are choppy with the throttle at high speeds.

 

Regarding coaching - I have always been very watchful for riders rolling on and off the throttle in corners, but I think this will make me more aware of the importance of a smooth gentle roll-on for faster riders and /or riders that are using a lot of lean angle, because I am more aware of how easily the tire can be made to slide with a rough roll-on- even on low-horsepower bikes. (The BMW electronics do a lot to smooth out rough throttle input, but I'll be more watchful for it on other types of bikes.)

[ktk_ace]

Hm, good questions.

 

Lessons learned:

1) You can't go very fast without good throttle control

2) I realized it is a lot easier to slide the tires with abrupt throttle actions than I thought - BOTH front and back.

3) You can break the rear tire loose with a lot less throttle than I thought - IF you slam it on very suddenly

4) Lack of control over the bike immediately captures ALL of your attention

 

I knew all the reasons why good throttle control is important and all the ways poor throttle control can cause problems, but being forced to experience those poor results made it more real to me how easily you can crash if you are choppy with the throttle at high speeds.

 

Regarding coaching - I have always been very watchful for riders rolling on and off the throttle in corners, but I think this will make me more aware of the importance of a smooth gentle roll-on for faster riders and /or riders that are using a lot of lean angle, because I am more aware of how easily the tire can be made to slide with a rough roll-on- even on low-horsepower bikes. (The BMW electronics do a lot to smooth out rough throttle input, but I'll be more watchful for it on other types of bikes.)

 

Given how advance the S1000rr is , Im thinking of adding a device to capture throttle positioning on the track to aid in coaching... good idea?

[Hotfoot]

 

Given how advance the S1000rr is , Im thinking of adding a device to capture throttle positioning on the track to aid in coaching... good idea?

 

Sure, that would be helpful - for one thing you could see how EARLY in the turn the throttle comes on.

 

There are other ways to observe this, though, that might cost less - for example we use a camera bike at CSS, and on the video review with the student you can SEE the throttle hand, and of course you can hear the engine, so it is easy to see/hear when and where the throttle comes on, how smooth the roll on is, and whether there are any hesitations or on/offs during the corner. Some gloves have white bits on the knuckles, that makes it REALLY easy to see, so a white strip of tape across the knuckles might make the throttle action easier to observe with a camera - actually, I think one of the Twist DVDs uses that technique.

 

Another interesting piece of data is an accelerometer, to show when the bike is slowing and when it is speeding up - GPS laptimers can do this too. This can be enlightening because sometimes you can be rolling on but still slowing down. In some turns or in high wind drag situations that is not always obvious - you FEEL like you are rolling on and the engine SOUNDS like it is revving up but that doesn't always mean you are gaining speed.

[ktk_ace]

Given how advance the S1000rr is , Im thinking of adding a device to capture throttle positioning on the track to aid in coaching... good idea?

 

Sure, that would be helpful - for one thing you could see how EARLY in the turn the throttle comes on.

 

There are other ways to observe this, though, that might cost less - for example we use a camera bike at CSS, and on the video review with the student you can SEE the throttle hand, and of course you can hear the engine, so it is easy to see/hear when and where the throttle comes on, how smooth the roll on is, and whether there are any hesitations or on/offs during the corner. Some gloves have white bits on the knuckles, that makes it REALLY easy to see, so a white strip of tape across the knuckles might make the throttle action easier to observe with a camera - actually, I think one of the Twist DVDs uses that technique.

 

Another interesting piece of data is an accelerometer, to show when the bike is slowing and when it is speeding up - GPS laptimers can do this too. This can be enlightening because sometimes you can be rolling on but still slowing down. In some turns or in high wind drag situations that is not always obvious - you FEEL like you are rolling on and the engine SOUNDS like it is revving up but that doesn't always mean you are gaining speed.

 

Got it! and noted too!

[YellowDuck]

The pipe on my bike is so loud (and the tone of the bike so different, being an aircooled twin), that my coach told me he could tell exactly what I was doing with the throttle any time he was following me. See, loud pipes may not save lives, but they make coaching easier!

 

BWWWAAAAAAAA.....brrrrrrrrrrrhhhhh....bwaaaaAAAAaaaaaAAAAAAAAAAAAAAAAAA....brrrrrrrrhhhhh...........

[gogogusgus]

Just curious, Hotfoot. Which bike were you racing?

[Hotfoot]

The MD250H (the Moriwaki)