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Opinions from experienced riders

Discussion in 'New Riders and Riding Tips' at netrider.net.au started by malJohann, Oct 17, 2014.

  1. So, I've been back to biking for two months now, after I took a five year break, and I need some opinions from experienced riders. I'm a fairly brisk rider (from what I've heard), and fairly often I find my handlebars going light and wagging a little from standing starts.

    Over the last week, this has happened twice coming out of slow corners, so basically almost a mono while still leaned over slightly. I don't feel like its a problem, apart from not having ever taken any advanced riders courses, and handled both occurrences in my stride.

    This is where I want some experienced riders to weigh in. What do you think? Slow down? As you were? Time for stunt school? :angelic:


     
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  2. wind on the power a bit later so youre not leaned over as much, there is a small risk you could loose the front when it touches the road again
     
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  3. Sounds to me like you are "Greedy with the throttle" that is winding on too much. Try twisting the throttle on earlier but slower, smoother and more progressively. That way you should have the bike more upright by the time you are getting stronger drive out of the corner. As Uncle Greg said, you could lose the front when it touches down again.
     
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  4. Try reducing the rear preload (I think the 390 has it), and/or a touch more rear tyre pressure.
    Mind you, if you're really getting the front off the ground mid-corner on 400cc you don't need my advice.
     
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  5. You guys are saying "could lose the front" and I read people "have lost the front" before. Could you guys elaborate on why one could lose the front? Could it come down too hard and not have enough initial traction for the lean angle? Could it come down misaligned to the direction of travel or lean? Does this all have to do with what your arms are doing with the handlebars to balance the bike on the back wheel?

    I feel my rear preload is a touch too low, bike sags about 10cm when I get on, its on its third lowest setting from a possible twelve, and I'm right at the top recommended weight that the bike was designed for (or so I've read). Tyre pressure at the back is right at 29psi, which is factory recommended for rider only (my bike is a single seater).

    Why do you say this? Inquisitive monkey wants to know!
     
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  6. We've only got 2 contact patches with the road, so if you want to stay safe it's best to keep both in contact with the road most of the time. :)

    Perhaps you could try leaning forward a bit to put a bit more weight over the front? Otherwise, as suggested above, start to throttle on a little bit earlier (ideally well before mid-corner) and make your throttle input more progressive.
     
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  7. Well then, it sounds like you are pressing the bike toward the limit of it's design envelope. Dukes (all of them) are naturally flighty at the front. You may well need to do as Greg, Senetor and Blueflame are saying until you get around to upgrading. (And even then... )

    I think it's the bike as much as your riding.
     
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  8. The front getting light when hamfisting the throttle is due to the weight transfer. You can do a few things to fine tune it, but TBH it sounds like your inputs are fairly course so first recommendation is for you to educate yourself and be more critical in your analysis of your own riding and bike setup. I don't mean to dress you down, but I would almost bet you are you not brisk by any standard and you only took it in your stride as you got lucky and it was over before you realised.
    You need to do something to address the transfer, whether it’s your throttle input or the bike setup. Your preload sounds ridiculous (should be closer to ~30-35mm on a road based sportsbike). Measure it properly, precisely, and get back to us. Use something like http://racetech.com/articles/SuspensionAndSprings.htm and pay attention to doing it absolutely properly measuring stat
    FWIW with 99% certainty a bike is set up for no one – the correct spring rate is based on a number of things, not only sag, including rider preference based on the requirement of their experience, so even 2 riders of the same weight, same tyres, on same road/track may have different spring rates. Another example of complexity, new riders develop their skills, and find due to their maxtreme braking and acceleration they need stiffer springs, as their skills develop their inputs smooth, and they need softer springs. So don’t assume anything is made with you in mind and especially broad statements like the bike was made for someone of your weight, please.
    & nothing wrong with a power wheelie coming out of corner, on a track. On the road it will end in tears eventually, nobody needs to provide examples for that to be self evident.
     
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  9. Is your 390 turbocharged or something?

    Or maybe you are riding it while sitting on the pillion seat? Ha. :p

    Yes you need to lean forward to put a bit more weight on the front wheel. I've noticed this works really well with the 390. There is a sweet spot. More preload was good too.
     
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  10. #10 malJohann, Oct 17, 2014
    Last edited by a moderator: Oct 17, 2014
    Sounds like I need to sit forward, force more weight through the bars, and be a little smoother with throttle input (although I've never thought of my inputs as harsh at all). Also thinking that upping the rear preload may help put the weight bias toward the front, would that be correct (I'll check out that link and go measure it properly)? Do I need to go get my shocks rebuilt/tuned to match my preference/skill/weight?

    No turbo, but something (a piggyback ECU), no pillion seat on it either, been replaced with a cowl. :wacky:

    I'll work on my technique, taking some advice from this thread, and make work of getting a C-spanner.
     
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  11. Another thought about your technique, you could be too stiff on the bars. You can get headshake coming out of corners when your arms are too stiff on the bars and there are small bumps or ripples in the road. This too can make the front seem light and vague. By putting more weight on the front, you will only be stiffer and make it worse. So when you ride next be mindul that you are not stiff on the bars. If you get arm pump when you ride, then you are hanging on too tight and too stiff on the bars.
     
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  12. #12 ibast, Oct 17, 2014
    Last edited by a moderator: Oct 17, 2014
    What's the thought with the preload? that seem almost the opposite of what I'd would be looking at.

    I'd say increase rear compression damping. Maybe decrease front rebound damping also.

    I'd say it's more than a touch too low. Increasing preload will get the front more planted. Some claim that it will make the front too flighty, but that's only if you go too far. You are not near that limit at the moment.

    This could be a significant contributor to your problem.

    In fact, the more I think about it, you are way under on preload there. You must have only 50mm of travel left.

    Also, 29 seems like a comfort setting. Try experimenting with more pressure.
     
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  13. Are you talking about turns of preload or ride height?
    390 only has preload on rear, no other adjustment AFAIK.
     
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  14. Preload and ride height are effectively the same thing (if there is no separate ride height adjustment).

    If there is no other adjustment, then given the riders weight, they may eventually up for a shock rebuild to suite them. I'd be getting the preload right first, however.
     
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  15. Yep agree, you were right, I was wrong.
     
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  16. That could be a Netrider first.
     
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  17. @malJohann@malJohann - never experienced that on my Duke in all my track days.

    I'm a 'light' 92kg. Standard setting gave 52mm of travel at rear. Experimented at track days and ended up with two clicks stiffer from standard to get the back end 'feeling' right. There is a bit of weight transfer between braking and power on from front to back - are you 'on the throttle' before you accelerate or starting from a closed throttle (engine braking) and then start accelerating when the front starts feeling light?
     
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  18. #18 malJohann, Oct 17, 2014
    Last edited by a moderator: Oct 17, 2014
    Not at all, my hands are relaxed on the bars, I picked up the wagging from the grips oscilating back and forth between my fingers and palms.

    This is what I was thinking, that my preload is way too low. Also, I'll bump the pressure up to 31 tomorrow and see how it goes.

    The 390 has only rear preload adjustment, and no compression or rebound adjustment on the front or rear either.

    I'll try what I can with what is adjustable, and if I'm still not happy in the end, I'll look to a rebuild to suit my needs.

    92kg is me kitted up with a backpack LOL! This was coming out of turns, so neutral to slight acceleration and then a fairly quick transition to WOT as the bike gets upright enough.
     
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  19. I find it hard to believe that you could be experiencing these events, without knowing why, and without knowing how to correct them...
     
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  20. Okay.
     
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