Twitchy Throttle Response Hindering My Roll-On and My Confidence

[trueblue550]

I typically ride a bike with an inline four that I would descibe as buttery-smooth when rolling on the throttle mid-corner. However, recently I've been spending a lot of time on a V-twin with strong engine braking and a very lurchy throttle, especially in the lower gears. When cracking open the throttle in a turn, the transition from engine braking to acceleration is sudden and noticeably destabilizes the (relatively soft) suspension. I have been trying to be delicate with the initial opening but so far I haven't been able to eliminate the jerk completely. Often this causes me to hesitate opening the throttle until way to late in the turn. There is a lot of advice online and elsewhere on how others think one can remedy this, such as using an aftermarket tune or getting on the thottle at turn entry and using "maintenance throttle" until the normal roll on point. I don't buy that because it's contradictory to what I've learned so far. So my question is, is this just a characteristic of some bikes that I should live with, or should I be doing something differently to stabilize the bike during roll-on?

[Hotfoot]

I have almost no experience with V twins, but there are some things that can help with that problem in general, that might apply to your bike.

Have you tried turning up the idle? This is a common thing to do on a track/race bike so the rpms don't fall as much when off the gas and it can really help make the roll on smoother. It does have the effect of taking you into the corner a little quicker so be cautious when you first start riding it that way.  On an inline 4 I believe typical advice is to turn it up 500 - 1,000 RPM, but you should Google recommendations for your bike.

What gear are you using entering the turns, are you a gear lower than you need to be? Sometimes just entering a corner in a higher gear makes enough difference in smoothness to be worth it, especially on a bike with a lot of torque that can handle coming out at a lower RPM.

I assume you have checked for play in the throttle and cable, to eliminate any jerk or effort from just taking out the slack.

An aftermarket tune is, in my opinion, a great idea. The other suggestions above don't cost anything, and this does, but you can get a really nice improvement in throttle response from working with a tuner and a dyno. Tunes that I have done on my bikes have yielded performance in power but MUCH more benefit in the area of getting better throttle response. (Better meaning, working how I wanted it to work!)

[Lnewqban]

If your in-line four is carbureted and your V-tween is fuel injected, you should feel the difference.

Besides the above recommendations, you could remove any current rotational slack between rear wheel and sprocket.

If everything fails, I would experiment by carefully using a little bit of clutch or rear brake simultaneously at the begining of rolling the throttle on (not by the book or desirable, but better that upsetting the chassis).

[trueblue550]

Thanks for the input. I'm hesitant to play with the clutch mid-corner because I could do a lot more harm than good if I mess it up. Cornering in a higher gear does help some and I'd take lugging the engine a bit over destabilizing the suspension. I think an ecu tune might be my next step. I've heard mixed reviews; some people say they gained 15hp and some say no change. If I can get smoother throttle response and a higher idle speed out of it, that'd be great. Any recommendations for where to go for a tune?

[JohnCBoukis]

Is there a vacuum synchronization on this bike and has it been performed regularly? An imbalance in vacuum between the two cylinders will exaggerate the V-engine's poor off-idle response.

[trueblue550]

A throttle body sync was done when the bike was new at 600 miles, and another one is due in about 1000 miles. I think I'll do it this weekend, thanks for the input.

[rmjr7@msn.com]

Just a thought from my experience and opinion: Try not to limit yourself to one particular view of teaching and open your mind beyond the constraints of your schooling. Store what you've learned to your skill toolbox and make a judgement for every given situation (every turn). Then you can exploit what you've learned to find what works best to inspire confidence in your riding. Then you become your own coach.

I have four bikes that behave completely differently when it comes to throttle control. Between riding my 17' S1KRR, 14' Monster 796, 15' Panigale 899, and 94' ninja EX500 (track only) they all require different timing and "finesse" for all varying types of turns. The ducs are "L-twins" which makes them even more touchy than v-twins. The panigale is even MORE difficult to ride smoothly than the monster as ducati switched to drive-by-wire and their throttle control is "touchy" to say the least. Both L-twins require significantly more finesse with throttle inputs for a smooth ride and more "attention" than my BMW and Kawasaki. They also require you to stay in an appropriate power band which makes inputs much smoother and less choppy. 

That being said,  you've already mentioned applying throttle early on which can settle the bike and make your throttle roll on smoother. This partially comes from loading the suspension and chain (feel it out and experiment). However, rolling on too early prevents your ability to load the front tire into the turn (if you trail break), can widen your line, and you often have to lean more than you normally would to make the turn (unless you tighten it with the rear brake). This technique may inspire confidence for some turns but definitely not for all. If you can afford the lean angle, go for it but don't make it a habit as it reduces available options on the street.

For the monster on the street, I typically make an effort to be in the appropriate RPMs and very finely roll-on until I feel everything get tight. Then I maintain that until I roll on continuously throughout remainder of the turn-typically as soon as I know I'll make the exit. Remember than when you lean the bike, your rpms will increase as well and if you're in a gear too low you can run out of revs quickly in a low revving v-twin engine.

The panigale 899 is notorious for its touchy throttle and engine braking. For this bike I use even more finesse with similar technique as the monster above and it makes me a better rider on the monster.

The most important thing you can do is remain relaxed in your hands. It's difficult to make 1mm throttle inputs when you have a death grip or you are weighting your arms. Be conscious of your body position and what you are doing with your legs. Perfecting your riding on a difficult bike with a touchy throttle will make riding a smoother bike that much easier-trust me. Hope this helps!

 

-JR