Clutchless gearshifts

[Guest Britcheflee]

So, now I am feeling more comfortable with my new bike I tried a couple of clutchless gearshifts on a ride today - just going up through the gearbox - I was a bit nervous even though I used to do it a lot on my Yamaha years ago as to me relatively speaking the gearbox is a bit more clonky anyway - gears went in smooth as silk - I was wondering though, does this do any harm if they go in smoothly or are you forcing the gears to change when you dont use the clutch?

Thanks,

Lee

PS perfect fall ride - although the sun is getting low in the sky now making it a bit difficult to see sometimes.

[Martin Barrett]

You'll be starting an oil thread next

[Guest ratchethack]

For some of the fun previously aired on this topic, see the discussion here:

 

http://www.v11lemans.com/forums/index.php?showtopic=4104

 

FWIW, as discussed here and elsewhere, I've found that the smoothest, quickest, and *most satisfying* shifts on the Guzzi 6-speed V11 box are made with a light, very quick "fanning" of the clutch lever only an inch or so, just enough to separate the clutch plates slightly, and preloading the shift lever slightly before the shift.

 

BAA TJM, & YMMV

[Martin Barrett]

My take is that, motorcycle gearboxes because of the way that they are designed can clutchless change. The advantage is mainly for racers who gain fractions of seconds. The clutch removes the loading on the gearbox enabling it to change smoother and may well reduce the impact of the dogs etc. The clutchless change may increase the wear. (certainly when you get it wrong)

 

I think if you compare a racer box that might even get ratios changed for different tracks and the life span of the bike any increase wear will be acceptable

To me there is no advatage in clutchless changes in normal riding. I have done it in the past but wouldn't do it in all circumstances so why bother at all.

 

Handy to have a go so if your clutch cable or hyrdraulic seals go you can still ride home. Watch out for finding neutrals when you need to stop

[Guest Britcheflee]

Yikes!!! Guess I went and poked the hornets nest!!! I just did it today to see if I could still do it - went in nice and smooth - however the majority of the time I will probably use the clutch as you mention - However here is another question - do you 'blip' the throttle when you downshift? I actually have found that the gearchanges on my bike are smoother without doing this but on the older bike it seems to improve things going down the gearbox? I guess in the old days they called it double declutching or something - a habit I still have when driving manual cars as my dad used to do it.

 

Lee

[Guest ratchethack]

do you 'blip' the throttle when you downshift?  

Absolutely! It's impossible to have a smooth downshift without a match (or close to it) in RPM between the cogbox mainshaft and the crank.

I guess in the old days they called it double declutching or something - a habit I still have when driving manual cars as my dad used to do it.

To double clutch, you engage the clutch in neutral between gears and use the throttle to match trans RPMs to engine RPMs. This isn't possible on a sequentially shifting constant-mesh box such as on the Guzzi and virtually all other moto's.

 

I also habitually double-clutch synchromesh transmissions. I had a Volvo one time with a 4-speed box that I could pretty effortlessly take upward and downward through the gears without the clutch by matching RPMs and using the throttle. I think it was so easy on that car because the trans and engine were small and had relatively low mass. Synchro rings help immeasurably. I got to the point where theoretically, (as long as I got the RPMs close enough) I only needed the clutch to start it and to stop.

[Murray]

Kinda drifting off topic, doubble clutching a synchromesh box is actully really bad for it. It makes the syncro cones works twice as hard to match the various shaft speeds shortening thier service life dramatically. On a bike gearbox not so much of a problem. However do not get sucked into trying to flat change a Guzzi dirt bike style, probally not so much on the fuel injected ones but on the older ones if you found a false neutral really good way to over rev the motor and bend a valve or two.

[Baldini]

I found clutchless up changes on the Scura felt real good, better than any change using the clutch. Just slots straight in. Felt like this was how the box should be used. Only did it much on trackday (probably only 3/4/5). You gotta be on it to get it right - relaxed don't do it. I'm also worried it may cause wear but it's hard to see how something that feels so slick can do any harm?

 

KB

[Guest Nogbad]

If you get it right, no problem. If you get it wrong you subject the dogs, splines, internal cush drive, u/js and bevel box to a jarring shock load and can break the rear wheel traction in the wet.

 

But, if you think it's cool to do..... (There isn't any other reason)

[Guest ratchethack]

doubble clutching a synchromesh box is actully really bad for it. It makes the syncro cones works twice as hard to match the various shaft speeds shortening thier service life dramatically.

Murray, I've heard this one my entire life and I tend to dismiss it with the understanding that using many things wears them out. I think of synchro rings not as a short-term "consumable" like brake pads, but as a longer-term "consumable" designed to be used up with some to spare over the lifetime of the transmission. I've put literally hundreds of thousands of miles on many manual transmissions downshifting with the double-clutch technique without any evidence of prematurely using up the synchro's - I'm driving one of 'em now.

 

BAA, TJM, & YMMV

[mike wilson]

Murray, I've heard this one my entire life and I tend to dismiss it with the understanding that using many things wears them out.  I think of synchro rings not as a short-term "consumable" like brake pads, but as a longer-term "consumable" that may be comfortably used up over the lifetime of the transmission.  I've put literally hundreds of thousands of miles on many manual transmissions downshifting with the double-clutch technique without any evidence of prematurely using up the synchro's.

 

BAA, TJM, & YMMV

68206[/snapback]

 

The only thing I've known that wore a synchro box early was a friend who had a habit of shoving it into first (keeping clutch depressed) at about 20mph when approaching junctions, ready to move off. By around 60,000miles (owned from new) there was a noticeable whine from first. But it still worked perfectly.

 

m

[Guest ratchethack]

The only thing I've known that wore a synchro box early was a friend who had a habit of shoving it into first (keeping clutch depressed) at about 20mph when approaching junctions, ready to move off.  By around 60,000miles (owned from new) there was a noticeable whine from first.  But it still worked perfectly.

 

m

68209[/snapback]

Now THAT'S transmission abuse without justification.

[Martin Barrett]

Now THAT'S transmission abuse without justification. <_>

68211[/snapback]

 

The other classics are resting foot on clutch and hand on stick shift (there I can speak Yank ) take up the slack and cause thrust bearing wear etc

[Guest ratchethack]

The other classics are resting foot on clutch and hand on stick shift (there I can speak Yank    ) take up the slack and cause thrust bearing wear etc

68213[/snapback]

Eh? How do you say "stick shift" in English, then?

 

Self-limiting behaviors seemingly abound.

 

How about holding the car on an upward slope waiting for the light to change by slipping the clutch in gear at idle? I've seen this one quite a bit too.

[mike wilson]

Eh?  How do you say "stick shift" in English, then?

 

How about holding the car on an upward slope waiting for the light to change by slipping the clutch in gear at idle?  I've seen this one quite a bit too. <_>

 

Self-limiting behaviors seemingly abound.

68215[/snapback]

 

"Gear lever" or "Gear stick". Above behaviour? Darwinism for motor vehicles. 8-)