French Bikes - Clutchless setup - why?

For you French Gurus out there, can you explain a bit why people run mobys and maybe Pugs clutchless (talking no front or rear clutch) and what advantages and disadvantages it has over either a front or rear clutch? how the launch is, how long the belt lasts, etc.

Re: French Bikes - Clutchless setup - why?

NEMA Victor (3 Knees Down) /

Clutchless means no idle and you have to tune it well since there is no clutch to compensate for sloppy low speed tuning.

Advantages include less rotating mass which means more top end and faster acceleration in some situations.

Belt wear is the same unless you are using a launch lever to slip the belt, in which case idk, more wear over time I guess?

Re: French Bikes - Clutchless setup - why?

> NEMA Victor (3 Knees Down) Wrote:

> -------------------------------------------------------

> Clutchless means no idle and you have to tune it well since there is no

> clutch to compensate for sloppy low speed tuning.

>

> Advantages include less rotating mass which means more top end and

> faster acceleration in some situations.

>

> Belt wear is the same unless you are using a launch lever to slip the

> belt, in which case idk, more wear over time I guess?

Less rotating mass does not effect mph

Re: French Bikes - Clutchless setup - why?

Dirty30 Dillon /

> Rocco Taco Wrote:

> -------------------------------------------------------

> > NEMA Victor (3 Knees Down) Wrote:

>

> > -------------------------------------------------------

>

> > Clutchless means no idle and you have to tune it well since there is

> no

>

> > clutch to compensate for sloppy low speed tuning.

>

> >

>

> > Advantages include less rotating mass which means more top end and

>

> > faster acceleration in some situations.

>

> >

>

> > Belt wear is the same unless you are using a launch lever to slip the

>

> > belt, in which case idk, more wear over time I guess?

>

> Less rotating mass does not effect mph

Simply not true.

Re: French Bikes - Clutchless setup - why?

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> > Rocco Taco Wrote:

>

> > -------------------------------------------------------

>

> > > NEMA Victor (3 Knees Down) Wrote:

>

> >

>

> > > -------------------------------------------------------

>

> >

>

> > > Clutchless means no idle and you have to tune it well since there is

>

> > no

>

> >

>

> > > clutch to compensate for sloppy low speed tuning.

>

> >

>

> > >

>

> >

>

> > > Advantages include less rotating mass which means more top end and

>

> >

>

> > > faster acceleration in some situations.

>

> >

>

> > >

>

> >

>

> > > Belt wear is the same unless you are using a launch lever to slip

> the

>

> >

>

> > > belt, in which case idk, more wear over time I guess?

>

> >

>

> > Less rotating mass does not effect mph

>

> Simply not true.

Please explain!

I thought rotating mass was more of a torque thing. I can’t see it directly effecting mph and if so its not really noticeable unlike the torque gains.

Okay maybe if lighting the part made it more efficient with less friction build up.

Re: French Bikes - Clutchless setup - why?

Please don’t make definitive statements if you don’t understand something.

Re: French Bikes - Clutchless setup - why?

> Ben Whittle Wrote:

> -------------------------------------------------------

> Please don’t make definitive statements if you don’t understand

> something.

Hence the words “please explain” “I thought” & “maybe

Dont just say not true and back it up with no explanation....teach me (edited)

Re: French Bikes - Clutchless setup - why?

Dirty30 Dillon /

If you remove rotational mass from an assembly, it can accelerate to peak RPM faster, which obviously increases acceleration. But, having less rotating mass also allows your entire assembly to spin faster overall, increasing top end power gains and overall speed.

It's never bad to remove weight from your rotating assembly, but it can be bad to remove weight solely from one end. (edited)

Re: French Bikes - Clutchless setup - why?

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> If you remove rotational mass from an assembly, it can accelerate to

> peak RPM faster, which obviously increases acceleration. But, having

> less rotating mass also allows your entire assembly to spin faster

> overall, increasing top end power gains and overall speed.

>

> It's never bad to remove weight from your rotating assembly, but it can

> be bad to remove weight solely from one end.

I wanna see this! I really have a difficult time picturing and engines internal parts spin at a faster top speed just because the part is lighter.

Whatever: If dirt Dillion said it, it must be true.

So I’m actually gaining mph without even noticing it or caring, wow! Best tuner ever

I not saying lighting parts makes you gain mph, because Im not making any false statements lol

Re: French Bikes - Clutchless setup - why?

this sounds complex

Re: French Bikes - Clutchless setup - why?

Dirty30 Dillon /

To be fair, Victor never mentioned mph's, he said more top-end. Which is a colloquialism way of saying top-end power, a.k.a. power at rev.

Re: French Bikes - Clutchless setup - why?

It is my current understanding/belief that standardized testing would show *negligible* differences in HP (Power) and RPM between two engines with differences in mass being the only variable.

That being said, I choose to interpret Victor's: "more top end... in some situations," as a real world practical consideration. MORE, not HIGHER.

With the same Power, you would need less time to get things up to speed. and because you usually brake to stop instead of coast, that means MORE time using power for propulsion instead of mass investment.

and the bike's weight will be marginally lighter, which again increases acceleration. which is more TIME going fast. which can be interpreted as MORE top speed, not necessarily HIGHER. (obviously not the primary point here, but still valid).

Also if you have no clutch, (in a perfect world with no belt slip) then you aren't wasting power making heat trying to get it to the wheel. Like trying to drink from a firehose.

consider trials bikes modifications on the other end of the spectrum. people often add rotating mass/flywheel weight to help with "more low end" power. If tuned with the other systems of the engine, it will help keep the bike in the low powerband longer, and with positive clutch engagement. so you are investing all of the power you can in the inertia bank to make things more tractable. (insert water drinking analogy here).

as far as french mopeds go, I think the "clutchless" setups I have seen were for simplicity. they still have a clutch, just in the form of belt slip.

I would consider racing without a clutch if the track was appropriate - which I am assuming would be higher corner speeds and longer straights. I've never ridden with one, but i'm certain you could tune/gear it for short stuff. typically geared for top speed, using clutch to get off the line. but ideally the variator has such a range that you spend as little time possible slipping the clutch to get out of corners, but still has full range to achieve top speed.

just my 3¢

Re: French Bikes - Clutchless setup - why?

> Rocco Taco Wrote:

> -------------------------------------------------------

> > NEMA Victor (3 Knees Down) Wrote:

>

> > -------------------------------------------------------

>

> > Clutchless means no idle and you have to tune it well since there is

> no

>

> > clutch to compensate for sloppy low speed tuning.

>

> >

>

> > Advantages include less rotating mass which means more top end and

>

> > faster acceleration in some situations.

>

> >

>

> > Belt wear is the same unless you are using a launch lever to slip the

>

> > belt, in which case idk, more wear over time I guess?

>

> Less rotating mass does not effect mph

855EE4A6-18C6-4807-8637-8A99D9D89A9F.jpeg

Since Victor is the moped gp champion I’d like to think he knows more than you rocco.

Why don’t you get back to modifying pipes to make them slower now.

Re: French Bikes - Clutchless setup - why?

Cool, so the main advantage is simplicity.

All the weight shit is blah blah blah. Got it

Re: French Bikes - Clutchless setup - why?

> ian c Wrote:

> -------------------------------------------------------

> Since Victor is a moped gp champion I’d like to think he knows more

> than you rocco.

>

fixed it for you

Re: French Bikes - Clutchless setup - why?

> ian c Wrote:

> -------------------------------------------------------

> > Rocco Taco Wrote:

>

> > -------------------------------------------------------

>

> > > NEMA Victor (3 Knees Down) Wrote:

>

> >

>

> > > -------------------------------------------------------

>

> >

>

> > > Clutchless means no idle and you have to tune it well since there is

>

> > no

>

> >

>

> > > clutch to compensate for sloppy low speed tuning.

>

> >

>

> > >

>

> >

>

> > > Advantages include less rotating mass which means more top end and

>

> >

>

> > > faster acceleration in some situations.

>

> >

>

> > >

>

> >

>

> > > Belt wear is the same unless you are using a launch lever to slip

> the

>

> >

>

> > > belt, in which case idk, more wear over time I guess?

>

> >

>

> > Less rotating mass does not effect mph

>

> Since Victor is the moped gp champion I’d like to think he knows more

> than you rocco.

>

> Why don’t you get back to modifying pipes to make them slower now.

I really hope he’s smarter then me too! I will get back to modifying my slow pipe if I want to. I gotta get to one of these moped gps, My mopeds all run like shit so it will be really funny to compete with someone that takes this stuff so seriously.

I like air leaks, I tune around the air leaks!

I feel like it would be way worse if I said “ rotational weight effects mph” but ether way you would of said something in reply.

It could happen but I’m not making and promises because I don’t know

Kid wants more mph, I can’t promise that, he gains mph and is still pissed at me :) (edited)

Re: French Bikes - Clutchless setup - why?

Rotational mass does directly effect mphs (edited)

Re: French Bikes - Clutchless setup - why?

since things seem a bit contentious, let me add more.

Rocco is correct in that reducing rotating mass does NOT affect steady state power output.

in other words, prolonged WOT runs will net the same ultimate top speed. a load bearing (NOT inertial) dynamometer will show the same HP.

however, these types of situations are not often encountered in real world scenarios. the vast majority of riding time is either speeding up or slowing down, and in those cases reducing rotational inertia offers benefits in that delta rpm/time (and therefore rate of accel/decel) can be increased.

bottom line: no delta rpm, no benefit. more delta rpm, more benefit.

the same holds true for ALL rotating parts on ALL vehicles.

Re: French Bikes - Clutchless setup - why?

This is the same as saying 20 pound wheels reach the same top speed as 1 pound wheels right? But the 1 pound wheels accelerates quicker?

Re: French Bikes - Clutchless setup - why?

> Dickie Thompson Wrote:

> -------------------------------------------------------

> This is the same as saying 20 pound wheels reach the same top speed as 1

> pound wheels right? But the 1 pound wheels accelerates quicker?

I believe you have it right , provided the same amount of energy is equally applied , start to finish .

Ever pick something up that you thought was heavy and it turned out to be very lightweight ? That lightweight piece probably almost flew out of your hand as you nearly slapped yourself in the face . ;)

Re: French Bikes - Clutchless setup - why?

> P D Wrote:

> -------------------------------------------------------

> > Dickie Thompson Wrote:

>

> > -------------------------------------------------------

>

> > This is the same as saying 20 pound wheels reach the same top speed as

> 1

>

> > pound wheels right? But the 1 pound wheels accelerates quicker?

>

> I believe you have it right , provided the same amount of energy is

> equally applied , start to finish .

technically, no: the rotating mass has the same effect as static mass on the vehicle. it is intuitive that a heavier vehicle actually takes more *energy* to accelerate to a given speed (and has to dump more energy to slow back down again). the same is true for rotating mass.

the key difference between the two is a measure of magnitude... in the flywheel mass scenario remember that the engine is going from let's say 2k to 10k rpm. now add 1lb to the circumference of a 6" flywheel. at 2k rpm it's moving 37inches*2000 or 74k inches/ minute. at 10k it's 370k inches/ minute, a difference of 296k in/min.

take that same 1lb and just add it to your luggage and it only has to accelerate as much as the vehicle.. 5 mph = 5280 in/min, 40 mph = 42240 in/min, a difference of 37k in/min.

in this hypothetical situation the rotating mass carries an ~8x penalty vs static. in other words, that 1lb on the flywheel is the same as 8lbs in the backpack. both will eventually reach the same top speed on level ground, but the 8lb backpack will require more gas (energy), more distance, and more time to get there.

Re: French Bikes - Clutchless setup - why?

So , technically , yes . ;)

Re: French Bikes - Clutchless setup - why?

NEMA Victor (3 Knees Down) /

Man, MopedArmy never changes.

Yes more top end refers to more top end power. Let me rephrase what has already been said: clutchless = less rotating mass = quicker acceleration = more available energy (power) at given rpms (at pretty much the whole range given a vacuum).

I will qualify more mph vs more available HP with the reasoning that I'm looking at this in a real world scenario, i.e. the track.

On the track, we are concerned with getting to our theoretical top speed as quickly as possible (this is a generalization). For example at Grange in CA I can reach 58mph before the end of the straight on the uphill. My moped's top speed is almost 70mph on the same gearing given a quarter to half mile of distance. So I can do a bunch of things that can increase my speed before the end of the straight: shorten gearing since I'm not using that extra 12mphs at all, eat less potatoes, or remove the clutch.

If I remove the clutch it could realistically get me past 58mph before the end of the straight because I'm accelerating faster than with the clutch. My theoretical top speed is still the same, however, unlike if I just did a gearing change.

As a racer, I'm looking for power everywhere, not just overall speed. I want to make sure I am "on the pipe" and going down that straight away and if I can make a little more HP at 13k rpms which is what my pipe/cylinder/vario is tuned for, then yea I'm going to look at removing some rotating mass (which will also increase overall RPM but again it may or may not translate to more speed outside of a vacuum).

Either way, we've all gone off topic. Clutchless bikes have won championships in France. They are viable but personally I prefer my clutch until someone beats me without one.

Re: French Bikes - Clutchless setup - why?

Slipping the clutch generates a lot of drag and loss of inertia in the turns. There is also the problem of over revs, this where you are trying to decel, but the bike keeps pushing you forward until the clutch disengages. I’m not sure how to explain it any better, having a good rear disc or large drum will make it manageable, but having no clutch you get straight engine braking.

Re: French Bikes - Clutchless setup - why?

Perfect! This is good info.

Also something I didn’t realize. The moby clutchless setups have a needle bearing for the belt at idle. I always thought they just slipped a loose belt.

Thank you!

Re: French Bikes - Clutchless setup - why?

> NEMA Victor (3 Knees Down) Wrote:

> -------------------------------------------------------

> Man, MopedArmy never changes.

>

> Yes more top end refers to more top end power. Let me rephrase what has

> already been said: clutchless = less rotating mass = quicker

> acceleration = more available energy (power) at given rpms (at pretty

> much the whole range given a vacuum).

>

> I will qualify more mph vs more available HP with the reasoning that I'm

> looking at this in a real world scenario, i.e. the track.

>

> On the track, we are concerned with getting to our theoretical top speed

> as quickly as possible (this is a generalization). For example at Grange

> in CA I can reach 58mph before the end of the straight on the uphill. My

> moped's top speed is almost 70mph on the same gearing given a quarter to

> half mile of distance. So I can do a bunch of things that can increase

> my speed before the end of the straight: shorten gearing since I'm not

> using that extra 12mphs at all, eat less potatoes, or remove the clutch.

>

> If I remove the clutch it could realistically get me past 58mph before

> the end of the straight because I'm accelerating faster than with the

> clutch. My theoretical top speed is still the same, however, unlike if I

> just did a gearing change.

>

> As a racer, I'm looking for power everywhere, not just overall speed. I

> want to make sure I am "on the pipe" and going down that straight away

> and if I can make a little more HP at 13k rpms which is what my

> pipe/cylinder/vario is tuned for, then yea I'm going to look at removing

> some rotating mass (which will also increase overall RPM but again it

> may or may not translate to more speed outside of a vacuum).

>

> Either way, we've all gone off topic. Clutchless bikes have won

> championships in France. They are viable but personally I prefer my

> clutch until someone beats me without one.

Yea I probably wouldn’t of even commented if I looked at your name first. I know who you are dawg, I’m not going to act like I don’t.

https://www.mopedarmy.com/forums/read.php?7,4333044,4333261#msg-4333261

Can someone just add this info to the fucking wiki

Re: French Bikes - Clutchless setup - why?

> Rocco Taco Wrote:

> -------------------------------------------------------

> Yea I probably wouldn’t of even commented if I looked at your name

> first. I know who you are dawg, I’m not going to act like I don’t.

>

> https://www.mopedarmy.com/forums/read.php?7,4333044,4333261#msg-4333261

>

> Can someone just add this info to the fucking wiki

Why don't you ?

That's how a WIKI works . Anyone can contribute , any time . ;)

Re: French Bikes - Clutchless setup - why?

> P D Wrote:

> -------------------------------------------------------

> > Rocco Taco Wrote:

>

> > -------------------------------------------------------

>

> > Yea I probably wouldn’t of even commented if I looked at your name

>

> > first. I know who you are dawg, I’m not going to act like I don’t.

>

> >

>

> >

> https://www.mopedarmy.com/forums/read.php?7,4333044,4333261#msg-4333261

>

> >

>

> > Can someone just add this info to the fucking wiki

>

> Why don't you ?

>

> That's how a WIKI works . Anyone can contribute , any time . ;)

Cuz I’m Countryboy tuning we need someone with more credibility like dirty Dillion or three knees down.

Il post stuff on the wiki that I literally just copy (like port maps or gaskets).

Shout out to all my haters! Keep your friends close and your enemies closer. I like to be very nice to my enemies and confuse them and make them believe Im at there Mercy.

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