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Shifting without the clutch?

By EvanNaculum,
in DRZ400/E/S/SM

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youghrider

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Someone told me years ago that you could not shift without using the clutch. I up shift, down shift without using the clutch, not all the time and never under full power or max rpm's. My 2007 drz s has 11,000 miles on it and shifts perfect and have never had transmission problems.

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EvanNaculum

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Someone told me years ago that you could not shift without using the clutch. I up shift, down shift without using the clutch, not all the time and never under full power or max rpm's. My 2007 drz s has 11,000 miles on it and shifts perfect and have never had transmission problems.

What's the point of not using the clutch if you are riding slow? I use the clutch when I'm riding slow and don't want to piss off the neighbors but when I want to get to 60 in 2 seconds, it's time for no clutch/throttle wide open between shifting. Just put a little pressure on the shifter and when you back off the throttle, it's goes right into the next gear like butter.

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yellowdatsun

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Whoever "taught" you, didn't teach you well. Can you do it, sure. Is it great for the bike, probably not. There's a lot of things that you "can" do, that aren't necessarily good ideas. You're putting a lot of stress on the entire drive train when you do that. The entire engine, transmission, and driveline, are jolted when they "chunk" and the engine and tranny instantaneously change speed to mesh together. Not a great idea. Shifting up is better than shifting down when not using the clutch though. But still....I've been riding for many years now, and the only time I don't use the clutch is when I don't time it right, or don't pull the lever in far enough.

Edited by yellowdatsun
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EvanNaculum

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Yes it's all up shifting without the clutch. Whenever I down shift, I always use the clutch...I mean the whole point of shifting without the clutch is to accelerate quickly. If I need to brake quickly, I usually am not too concerned about shifting and more interested in not hitting whatever is in front of me :ride:

Edited by EvanNaculum
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bin

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2 years back I was invited to joint a friend at a race track for racing lessons, there was 4 people per group and 3 groups. Every one was riding a cbr600 what year I have no clue. Anyways, this one rider was always faster then me and I couldn't get my head around it, always like 2 second faster. After a few breaks between groups, we started talking about exiting a corner. Me being me I was talking with my hands and made a clutch movement with my hand, and the guy stopped me right there and said it's a good way to save time on the track. Next few sessions I ran about 1 sec faster on average.

I normally use my clutch on my drz but I ride for fun, if I raced I wouldnt even consider it up shifting.

Edited by bin
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EvanNaculum

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These are not my words, so I will quote:

"no you don't. motorcycles have constant mesh sequential transmissions. no synchros. you can upshift or downshift at any rpm without the clutch. won't even damage the trans. the clutch is there to get you out of first, and allow you to control how much power gets to the wheels, and how smoothly it's applied--in the case of downshifting, you're using it to reduce the driveline shock so you don't lock up the rear or overload it midcorner."

Read this on motorcycle forum.com

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yellowdatsun

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These are not my words, so I will quote:

"no you don't. motorcycles have constant mesh sequential transmissions. no synchros. you can upshift or downshift at any rpm without the clutch. won't even damage the trans. the clutch is there to get you out of first, and allow you to control how much power gets to the wheels, and how smoothly it's applied--in the case of downshifting, you're using it to reduce the driveline shock so you don't lock up the rear or overload it midcorner."

Read this on motorcycle forum.com

I've been riding dirt and street bikes for 20 years, and never heard this. Doesn't matter whether they're sequential, syncros, or whatever. It's bad.

Let's say you're riding a bike and the engine is at 5000 rpm. When you shift the engine without the clutch the rpm drops to, say 3500 rpm *instantly*. That inertia of the instantaneous change of 1500 rpm has to be absorbed somewhere. That force is transferred to the gears, sprockets, chain, and even through the engine piston, rod, timing chain and crank. You can't have a change in that kind of force without the energy going somewhere. It doesn't just magically disappear. It's the old saying, a force in motion wants to stay in motion. When you stop of slow it down, the energy needs to go somewhere. Using the clutch allows the gear change to happen slow enough so that the engine and transmission forces against each other are basically zero.

Edited by yellowdatsun
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Noble

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OK. Quote (me) "there is more to it then that". All transmissions, synchromesh or not, have to match the gear speeds. Automotive transmissions have relatively heavy gears and not much backlash in the egnagement dogs. Synchromesh is a system of blocker rings and cone brakes that slow the faster spinning gear for engagement on up shift. On down shift the synchromesh speeds up the slower turning gear for smooth engagement. Motorcycle transmissions have smaller lighter gears and get away without the syncho rings. They just use a lot of slop in the engagement dogs and use the dog clutch to slow (or speed) the gears at engagement. When using the clutch, the mismatched spinning inertia is absorbed by the gears and the inertia is only the gears and shafts an parts of the clutch. Without the clutch, the spinning inertia includes the motor, the weight of the bike and available traction.

Both motorcycle and automotive transmissions can be shifted without the clutch. Because of the blocker rings, automotive transmission gear speeds have to be closely matched by the driver to engage. A fairly slow tedious process. Auto transmissions that will be shifted clutchless on a regular basis have the syncho rings removed and more clearance added to the engagement dogs. Motorcycle transmissions are much more accommodating. Without too much practice they can be shifted smoothly without the clutch and without damage to the transmission. However done poorly, transmission damage is certainly possible and likely. It is a skill and technique that takes some practice. You can't just simply say a motorcycle can be shifted without using the clutch and no damage will ever occur. It is not as simple as that.

Dirt bikes are a bit different. Generally the transmissions are smaller and lighter than a street bike and the motor is also smaller and lighter (less inertia), traction on dirt is less than traction on pavement, gear ratios are likely to be closer and nobody expects them to last forever. What this means is it is even easier to shift dirt bike with no clutch and less concern on matching gear speeds. Just bang gears up and down.

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EvanNaculum

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Thanks noble...any tips on how to shift without the clutch properly? And I will quote you, "Without too much practice they can be shifted smoothly without the clutch and without damage to the transmission"

This style of riding might be reserved for racing, but everyday riding feels like the race track to me :devil:

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Craigo

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Ok, fine...you guys finally talked me out of it...I have put about 2,000 miles on the bike riding this way...no signs of trouble yet, but I will shift with the clutch from now on. Should I do any inspections to see if I damaged anything?

For what's required to inspect I personally wouldn't bother...The transmission will let you know through normal riding if there is a problem...

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