Improper Downshift?

Discussion in 'Gen II Busa Information' started by busanewb, Dec 11, 2016.


  1. busanewb

    busanewb Registered

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    Today I riding with some buddies and one of them I noticed was rev matching to downshift. I understand what it and how to do it but I'm wondering if that's the correct way? my buddy was explaining it's much better to rev match than to pull in the clutch, down shift, then to let out the clutch fast like I have been doing. he said it's harder on the motor, shift forks, and could lock up the rear tire. I personally have not had these issues but I do notice sometimes when I shift fast like that in traffic the shifts sound extremely harsh. I always thought it was fine since I was under the impression the bikes had a slipper clutch and it's suppose to help with that .
     
  2. nosbig

    nosbig Registered

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    You are both correct. With the slipper clutch it is hard to slide the back tire , but it can be done. Rev matching will not harm anything either.
     
  3. Rivercop UK

    Rivercop UK Registered

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    Its a doddle once you get the hang of it ... Just a very quick blip of the throttle as you slot it down a gear ... Doesn't have to be 8000rpm, just a little flick of the wrist. Makes the gears engage a lot smoother.
     
  4. busanewb

    busanewb Registered

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    Its mainly between 6th downshifting to 5th that i shift where i quickly release the clutch without blimping the throttle and it feels like a harsher downshift. Its the damn traffic of big cities that kill me so i dont really think about blimping the throttle before downshifting. Thinking im doing any major damage shifting like this?
     
  5. sixpack577

    sixpack577 Top Gun Registered

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    Just let the clutch out smoothly.
    To where it doesn't Jerk.
    No need to even rev it up.
    You can even shift up or down without the clutch. Just let off the gas, and apply light pressure on the shifter, and it'll slip into gear at the appropriate rpms.
    Thats even less stress on the transmission/clutch, as there is no abrupt stop/start on spinning parts.
     
  6. busanewb

    busanewb Registered

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    I often do the clutchless upshifting. Never tried it for downshifting. Mainly worried about damage. Definitely trying to work on my actual riding skills and not just worrying about going the fastest.
     
  7. sixpack577

    sixpack577 Top Gun Registered

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    As long as you don't force it in gear you're fine.
     
  8. busanewb

    busanewb Registered

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    Nah ive never forced it into any gear except during those false neutrals between 5th and 6th and the bike decides on its own if its going into 5th or 6th gear...
     
  9. Mythos

    Mythos Registered

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    I'm no expert but I always rev match AND use the clutch. It's just intuitive now to hit the right rpm and it snicks right in. Also, for more extreme sport riding on the street or track, slow clutch modulation can be just what you need entering a corner at high rpm. The slipper clutch is pretty harsh and I have never felt it come on except in first gear, maybe second----letting the clutch out fast. No sir, I say the clutch lever is one of your controls just like the brake and the throttle. Might as well use it. If you're smooth, I don't see how it could cause more engine wear. Maybe more clutch ware but I'd rather replace a clutch than an engine.

    Yeah, If you're not revving and just jamming it in fast, it's a little rough. As a rule of thumb, for normal street/highway rpm, pull clutch and rev up about 400~500 rpm just before you kick it down...it's almost simultaneous. The idea is to make the downshift as soon as you hit that extra 500 rpm. the engine spins up 500 rpm in a flash at almost any throttle position. If you are off by one or two hundred rpm, that is not the end of the world. You'll get it. Let the clutch out as slow as you need to. You can be your own slipper clutch. For high rpm downshifts, you will need to rev up more than 500. When you are just crawling along, you can just give it a quick snort for a smooth downshift.

    When you get the hang of it, you might leave the throttle steady, squeeze the clutch really quick (like a fraction of a second while tapping it into the next lower gear and release the clutch quick...it's swift gear change totally smooth as long as you never let off the throttle. Sounds totally badass. Use the clutch and even a little throttle to soften into the backtorque. You'll get the hang of this by sound but peeking at the tach might be the best way to start out. More rev for high rpm, less rev for low. You'll get the feel of what the bike wants.

    If you watch this video from about 1:35 maybe you will sort of get the idea of what I'm saying. Sorry about the noobish second half of the vid. this was 4 years ago. ..and I was still on and off the throttle like I was down shifting a dump truck but that old habit is gone now. You don't really need to close the throttle at all before doing the blip.

     
  10. Mythos

    Mythos Registered

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    What you want to do is AVOID doing the downshift if you revved way too high...x10 if downshifting to first gear. If you screamed it, just accept you blew that one and do a slow downshift with the clutch and no blip. The gears will synchronize without a blip if you you just pull the clutch and ease it in slow. Don't let the engine spin down and then try to decide what rpm you think you should rev to. or you probably get a big SLAM! uochy. did it once or twice on the busa, never found steel from shift dogs in the oil ever. I have found plenty on the 14 though...still shifting good.
     
  11. busanewb

    busanewb Registered

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    So I guess I'm a bit confused...

    Should I of definitely been rev matching while down shifting? I've never done this till my buddy even mentioned it, and that's when I noticed it feeling a bit harsh when just clutching down shifting and releasing the clutch quickly.

    Kind of worried about shift forks now. It's a low mileage bike only 2k miles...
     
  12. caspernz

    caspernz Registered

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    Rev matching on downshifts is a fairly basic riding skill, watch a few youtube videos to get the gist of it. Then try it at mild rpms (4-7k) and work your way up. Infinitely smoother and it soon becomes second nature.
     
  13. Rivercop UK

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    As you are braking the revs obviously drop ... You only need to add 1500 - 2000 revs from where you start the downshift. So as you pull in the clutch, 'blip' the throttle then snick down a gear .. Release clutch and your away again. You can see how little of the throttle you can turn if you are braking while downshifting ... So you don't need a big handful of gas.

    Its really easy once you get the timings right ... Everything should happen in about a second / second and a half. Clutch, blip, snick, release !!
     
  14. sixpack577

    sixpack577 Top Gun Registered

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    Just ease the clutch lever out.
    That's all you have to do.
    If you just let the lever go, it defeats the purpose.
     
  15. Mythos

    Mythos Registered

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    Not really. If you pull your clutch lever and press down on the shift pedal nice and easy and it goes in, that's ok. Ordinarily, the rpm will drop to idle when you do this. It's slower than rev matching. It's bound to feel a little more clunky or resistant in the shift pedal too. If you're just cruising around town, I think no rev is fine. I don't even know how it would work for higher rpm. That is probably where rev matching is the most important for speed and health of your gear box. Start practicing at low engine speeds. The higher rpms will require a higher rev but most times, it's just about 500 rpm for me. Just a quick snort (or no rev) if you are at very low rpm. I can't say I've ever looked at the tach but 1500 rpm sounds like a very big rev ....maybe if you are shifting down at 9000 rpm.

    The concept is: What rpm would I be at with my current MPH if I WAS in that gear I plan to shift down to. Rev to that rpm and tap the pedal down at the same time. You're just getting the engine to run at the normal rpm for the gear you are shifting down to. Highway speed, gears are about 500 rpm apart. So you're running say 3500 rpm at 60 mph and need to drop a gear, close the throttle, pull the clutch, rev to 4000 and stab the pedal down at 4000rpm. release clutch and ease into the throttle again. <<<This is the old Ford dump truck way to do it. Your busa's transmission is a lot slicker than that but I think it's a good way to start. When you get the feel of that, you will be able to do this without ever letting off on the throttle at all. Just pull clutch quick with throttle open and stab down. Now you are ready for racing!
     
  16. kml

    kml Donating Member Registered

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    With practice you can clutchless downshift with no harm to the bike.
    70thou kilometers on my 03 with clutchless downshifts from day one. Gearbox is still rock solid.



    Flame suit on... LOL

    cheers
    ken
     
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  17. sixpack577

    sixpack577 Top Gun Registered

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    100% agree
     

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