Clutchless downshifting | Page 2 | GTAMotorcycle.com

Clutchless downshifting

gsxr guy said:
I use my clutch on every shift. Up and down. 2 fingers and only enough to disengage. I don't know if you where watching from the wall last time we were both at tmp. But it is just as fast to upshift using the clutch as it is to not. And I have never had to do tranny work. I don't have a quick shifter.
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This is incorrect.
 
Not sure why anyone would use the clutch on an upshift really. Aside from 1-2. It's just unnecessary and wastes a few tenths every lap
 
gsxr guy said:
Lol. To each his own.
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Your shifts might not be as fast as clutchless, but with careful and calculating action it is possible to accelerate quicker while shifting using the clutch...... transmission has to be unloaded to shift.... If you use the clutch to do so, and can develop more inertia in the engine while using the clutch.... That inertia can be converted into forward motion......just don't loop.... and count on accelerated clutch plate wear.
 
casacrow said:
Your shifts might not be as fast as clutchless, but with careful and calculating action it is possible to accelerate quicker while shifting using the clutch...... transmission has to be unloaded to shift.... If you use the clutch to do so, and can develop more inertia in the engine while using the clutch.... That inertia can be converted into forward motion......just don't loop.... and count on accelerated clutch plate wear.
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Like power shifting in a car..... It's different in the bike world.

I always clutch on the way down, never on the way up.

Just my 2 cents


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reciprocity said:
If it wasn't faster without the clutch,, why would it be done??..

there are also safety issues that arise from using the clutch when your pace increases.
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My pace used to be fast enough that I had to run pro class at the national level. Now I am old and slow. :)
 
casacrow said:
Your shifts might not be as fast as clutchless, but with careful and calculating action it is possible to accelerate quicker while shifting using the clutch...... transmission has to be unloaded to shift.... If you use the clutch to do so, and can develop more inertia in the engine while using the clutch.... That inertia can be converted into forward motion......just don't loop.... and count on accelerated clutch plate wear.
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You explained this far better than I could. Thank you.
 
gsxr guy said:
My pace used to be fast enough that I had to run pro class at the national level. Now I am old and slow. :)
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If that's your definition of slow, I'd say you used to be retarted fast
 
nikiter said:
I always use clutch/rev matching (no slipper clutch here). What damage could be caused by not using clutch when downshifting?
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skapan said:
I always use the clutch to downshift at the track. The thought of a false neutral at the wrong time makes me want to make sure the lower gear engages. On the street not so much.
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casacrow said:
Can be hard on the dogs, Dawg.
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I'll just leave this here. I've broken THREE of these over the years, and the part is no longer available (I got the last one in Yamaha's worldwide distribution chain).



Obviously this is a weak point in the design of this particular transmission but the concept is the same on all of them. I had the gearbox that is now in my race bike cryo-treated. On the engine/transmission that I am working on now, I have also re-shimmed the output shaft so that there is less wobble, for lack of a better term, on the gear that this engages with and I am going to have it cryo-treated. I am modifying the cush drive in the (aftermarket) rear wheel of the race bike to soften its action. All shifting on this bike from this point forward, up or down, will be using the clutch. Even if you are unloading the transmission by closing the throttle ... having the clutch pulled in reduces the total amount of inertia of stuff that has to change speed instantaneously when those dogs engage.
 
Great post. Love the pic. I'm going to have to disagree with ya about using the clutch to better match speeds of moving parts. Would certainly help in a non sequential transmission where double clutching would help, but it's just not the case in our sequential trannys. If we could pass through neutral in all gears, it would be a different story.

The clutch will certainly make things smoother as you bring all the parts up to the same speed, but disengaging the clutch actually makes the moving bits start turning at seperate speeds faster.

Edit- nope yer right. Clutch will help reduce how quickly those parts have to match speed. Started thinking of my post before completely reading yours.

Brian P said:
I'll just leave this here. I've broken THREE of these over the years, and the part is no longer available (I got the last one in Yamaha's worldwide distribution chain).



Obviously this is a weak point in the design of this particular transmission but the concept is the same on all of them. I had the gearbox that is now in my race bike cryo-treated. On the engine/transmission that I am working on now, I have also re-shimmed the output shaft so that there is less wobble, for lack of a better term, on the gear that this engages with and I am going to have it cryo-treated. I am modifying the cush drive in the (aftermarket) rear wheel of the race bike to soften its action. All shifting on this bike from this point forward, up or down, will be using the clutch. Even if you are unloading the transmission by closing the throttle ... having the clutch pulled in reduces the total amount of inertia of stuff that has to change speed instantaneously when those dogs engage.
Click to expand...
 
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Correct me if I'm wrong but isn't the point of clutchless shifting to be faster? Therefore it seems unnecessary (lazy?) to clutchless downshift since you are slowing down anyway giving you time to engage the clutch? Seems like unnecessary wear on the gearbox to clutchless downshift. Fwiw I only clutchless upshift and use the clutch going down.


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You got it. When downshifting, you are slowing down anyhow. Might as well make life easier on all the mechanical bits, by using the clutch.
 
How else are you suppose to take advantage of your fancy slipper clutch if you don't use a clutch to downshift?
 
dricked said:
How else are you suppose to take advantage of your fancy slipper clutch if you don't use a clutch to downshift?
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Pfffff... autoblipper yoo
 
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