Weight of fly wheel different manufactures.

[section swept]

1 hour ago, cascao said:

Power (torque) come from engine. It is'nt altered by flywheel.

Flywheel is a rotating mass that can store momentum. It has two effects:

1) when engine is comming from a lower RPM to a higer RPM: Engine will increase rpm slower since it has an added mass to accelerate. It can increase traction due a less agressive behavior and it will decrease power burst you have using throttle.

2) When engine is comming from a higer RPM to lower RPM: Flywheel will give energy to system. Rotating momentum can be used to drive the motorcycle.

An side efferct is the engine runnig in a more steady way when travelling during a rough terrain like over a bunch of loose rocks or loose terrain. On malleability deppartment, it can increase the "heavy feeling" on motorcycle just like we feel on a big bore engine.

Had played with flywhhel a lot and my feeling is: It only good in specific conditions (mud, senior rider, MX bikes on enduro). https://youtu.be/16d-ewfc8lU For average Joe, most of time, better stick with what come from factory.

Manufacturer’s engine designer knows best! 

[section swept]

£Mean effective gas pressure acting through the con rod on the crankshaft big end journal (crank pin/ big end) when the crank gets to 90 degrees passed TDC the effective gas pressure disipates rapidly. 

Power is work done ....more revs means more work being done until the constraints of engine breathing, gas flow and combustion efficiency etc prevent any more effective work, so the engine may rev to say 9,000 rpm but produces max power (work done) at 7,500 rpm after this the effective work done tails off due to the aforementioned. Bigger valves, improved bresthing in the inlet, combustion chamber design and engine management controls such as ignition mapping and fuel delivery can improve and raise power at higher rpms.

Torque is the maximum leverage any engine can produce and this is usually lower down the rev range, a short stroke engine would be 2-3000rpm (example) lower than the max power rpm. Therefore torque is a moment of force in the rotational equivalent to linear force.

When engine revs were not so high in the years gone by it was sometimes the done thing to drill large holes into the flywheel(s) and pack with lead to increase flywheel weight and therefore create more inertia but the engines were slower to rev because the piston now had a heavier mass to turn. This mass took longer to slow down hence big old four stroke singles were able to lug up hills and through sections without much throttle input once underway. Some early strokers were also modded in this way by adding mass weight. 

Either way the original post asked for weights, irrespective of this and all previous valid and interesting replies, it really comes down to the space factor. The crankcases can only accept so much inside them as space is already tight. A larger diameter flywheel might be possible by adding an outside band to the original flywheel...welded in place, screwed in place or both...shrunk on would also work but secured again by additional devices or methods. Thats assuming it was achieveable and assuming the engine could deal with this increased mass....you may even suffer crankshaft windage or even shearing off due to the mass. One thing would be very real though and that is your engine will not respond to throttle inputs as readily as before. 

Rather than mess about why dont you go the more power route with a bigger bore or engine porting and ignition and fuelling modifications. The first starting point is rider weight, stamina and concentration. The next step is bike set up and maintenance, attention being to the brakes and smooth operation, suspension pivots etc and wheel free running, chain maintenance, cooling system, everything as the manufacturer intended.....then go for more power!??Dont forget to use the best quality fuel as well, no use us investing time with you if you skimp in important areas.

 

[feetupfun]

An interesting change was made by Beta during the 2000s in their two stroke Rev 3 range. They wanted to reduce the overall mass of the bike and one change they did was to change the shape of the crank wheels. They made them thinner and increased their diameter. The mass moment of inertia of the crank wheels remained the same but the mass of the crank wheels was reduced.

[leosantanalg]

16 hours ago, cascao said:

Power (torque) come from engine. It is'nt altered by flywheel.

Flywheel is a rotating mass that can store momentum. It has two effects:

1) when engine is comming from a lower RPM to a higer RPM: Engine will increase rpm slower since it has an added mass to accelerate. It can increase traction due a less agressive behavior and it will decrease power burst you have using throttle.

2) When engine is comming from a higer RPM to lower RPM: Flywheel will give energy to system. Rotating momentum can be used to drive the motorcycle.

An side efferct is the engine runnig in a more steady way when travelling during a rough terrain like over a bunch of loose rocks or loose terrain. On malleability deppartment, it can increase the "heavy feeling" on motorcycle just like we feel on a big bore engine.

Had played with flywhhel a lot and my feeling is: It only good in specific conditions (mud, senior rider, MX bikes on enduro). https://youtu.be/16d-ewfc8lU For average Joe, most of time, better stick with what come from factory.

Seems that you just backed up my point on number 2! Bazinga!

[faussy]

3 hours ago, feetupfun said:

An interesting change was made by Beta during the 2000s in their two stroke Rev 3 range. They wanted to reduce the overall mass of the bike and one change they did was to change the shape of the crank wheels. They made them thinner and increased their diameter. The mass moment of inertia of the crank wheels remained the same but the mass of the crank wheels was reduced.

Moto Guzzi were on to this in the 1920s

On 12/17/2018 at 3:46 PM, leosantanalg said:

I have to completely agree and disagree with you. The heavier fly wheel can not generate torque indeed! torque is only generated by the engine.. The heavier flywheel will do is have more inertia. and that inertia means punch power when you let your clutch out with a full Throtle that has been wide open for 1.5 full second.  imagine that:  put your bike on a stand with the rear in the air in 3rd gear and clutch on wide open so the wheel will spin as fast as you can then suddenly press the clutch and jam the rear brake! that's replicating what happens in the flywheel/clutch.  Then do the same experiment but this time pack the rear rim with some lead weight distributed evenly. when you jam that brake, you better be holding the bike!!!   

Why dont you just get a beta 80, install a 10kg flywheel weight on it, wait your 1.5 seconds with the clutch in while its accelerated to speed, drop the clutch in front of your biggest hill, and then let us know how much more torque it has than my 300 gg

Edited December 18, 2018 by faussy

[leosantanalg]

2 hours ago, faussy said:

Moto Guzzi were on to this in the 1920s

Why dont you just get a beta 80, install a 10kg flywheel weight on it, wait your 1.5 seconds with the clutch in while its accelerated to speed, drop the clutch in front of your biggest hill, and then let us know how much more torque it has than my 300 gg

why don't You and I just park the bike side by side , put in neutral and hold the throttle wide open to see what bike quits first??? #%^$&^*

I m not the smartest and most knowledgeable in Trials but my point has some sort of validity. I don't think it should be taken as a joke. It all started from a friend of mine that is a professional drifter and he was explaining why drifters put lighter fly wheels on their rides. When they enter a turn they "kick the clutch" to increase the RPMs so they can start drifting by spinning and loosing traction. the reason for a lighter Fly wheel in that case (acording to him)  is to allow a fast pick up in RPM since you can only kick that clutch for a split sec... in trials we have plenty of time to raise RPMs ( in which point the Torque is gone for both 2 and 4 strokes) so adding weight to the fly wheel would technically have the reverse effect. your engine will take longer to reach the high RPM but when you dump the clutch, inertia of rotation should favor the initial "punch". from there on, I cant really testify but if Physics still works correctly, please en-light me what I am missing.  if the Beta 80 could accelerate a 10kg fly wheel fast enough, all I can say is that the beta front wheel would leave the ground before your gg300. after that, of course that engine cant carry on the rotation... just saying... my original question is all about a "Splatter" and the "punch" the split sec when goes from disengaged to engaged.   Enjoy the GG300. when starts is a great bike LMAO

[oni nou]

On ‎12‎/‎17‎/‎2018 at 1:52 AM, lineaway said:

  That is why they came out with a 300 instead of a 250. Do you really think a 300 4 stroke makes as much power as even a 250 two stroke? No , not even close.

When people discuss things on here ; as in  discussions about things in life in general the basics get forgotten and the argument drifts onto some other angle ........for all of  those who liked this or say thanks are applauding the fact that a 4 stroke motor of 300cc does not even make the power of a 250 2 stroke motor ....If we relate that to what we are actually talking about  it is irrelevant. The geezer who posted started riding trials a couple of years ago on a GasGas txt contact 250 [the new model] then he changed to a Sherco 300 factory .......given that he has been only riding for a few years my guess is that he is not capable of riding sections of the standard that Pat Smage can ride.... if he could we would know about it no doubt. If he rides as an Expert in club trials in the USA  why would any one in their right mind pay the price of a Honda 300RR for a bike that did not  have the power output of a 250 2 stroke if that was a limiting factor. As all this relates to Trials riding which is more technique related than power for example British rider Nigel Birkett as a factory Montesa rider used the 348 motor and had  poor results but when he was asked to try the new 200 he started to win [riding the same elite class ]Then you have the Fantic 156cc motor that at club level sees many beating larger cc bikes that can be modern 300 cc mono shocks .......In the UK there is a rider that uses a 175 Majesty and regularly wins the clubman route against modern monoshocks including the latest models that are rip snorting 300cc machines .To make the Honda 300RR world class it takes the addition of approximately 11 to 20cc's with a specially tuned exhaust ..special  mapping, valves etc etc and the loss of approx. 6KG in weight with this difference between the production 300rr Bou has Beaten all 300cc 2 stokes with  their huge amounts of power over the severe sections that they ride since 2007.........in the amateur world; sections are NOWHERE near the same severity so bikes do not need to have the same power........taking that difference in severity into account  a 250cc 2 stoke motor should be adequate and in truth is all that is needed to get through the sections at club level or if you ride a 4 stroke then a 300cc....If Bou, Raga, Cabestany ,Fajardo and Busto turned up to ride the Expert route in a USA club trial in the Masters/Expert class all of them on Standard 2 STROKE  250cc machines against others including  Smage on a 300cc bikes I think everyone knows what the outcome would be [it would be very interesting to see what would happen with them on 200cc bikes ,,,the results would probably be the same] Anyway back to the fact that the OP owner rider of the 300rr is a relatively new amateur rider I think that the power produced by the 300RR is in all probability more than adequate for a rider of his ability if he uses the right techniques.....If he was at Pat Smages level then it would appear that the 300RR would be an absolute waste of time as its power output is so feeble .....it cannot even muster up enough GO as a 250cc 2 stroke....not without the addition of 11cc's and some very expensive tuning and 6kg of weight loss.

What people actually need power wise is one thing and then the need and search for 'POWER' as a manly hobbyists  obsession with power speed acceleration and After market power parts manufacturers dream is another.

I mean who in their right mind would buy a 300rr at that price  it makes a lot less power than a 250cc 2 stroke[The OP does not think so and he owns one and is comparing it to a  2018 300 Factory Sherco That he owned]  then you have the 4RT its basically a 125 2t powerwise Ha Ha

To all the Honda Montesa  riders I feel sorry for you with your pathetic amounts of power ................but you know different, you know the reality.

https://youtu.be/ljOPPvcxb2Y  Takumi Narita [Yes AGAIN] Scorpa TYS-F fart machine ......some one forgot to tell him he would need a 500cc motor to climb a hill like that.

Four stroke 300cc does not even make the power of a 250cc 2 stroke... no where near ......but if you add 20cc it makes more than a 300cc 2 stroke. https://youtu.be/JPnjtttrCfM?t=5m27s

Edited December 19, 2018 by oni nou

[lineaway]

You are more correct in that than most people would like to admit. I had a cota 200 stuck in the corner of my garage for 17 years until I was old enough to ride vintage events. It was like cheating as it had just enough power and handled well. Actually the stock Montesa makes it`s power in the wrong places for mere mortals and that is why it sucks in mud. And speaking of Pat vs a guy named Frexia, the bike Marc rode was not even close to a stock bike. It was quite exciting to get to watch both riders those two years. It really did push Pat, and he worked for the win the second year.

 Last Sunday was quite fun when we had about ten guys of all levels try a very hard corner which included many issues. First it was a very fine line, it dropped down and then suddenly had an up. all the while being a hard left turn and ended in a floater off a small wall. Not large or dangerous, just very hard to put it all together. (And just a little slick) The results were interesting. A 250 and a 260 4RT always spun too much, but a 300 4RT did it ok. A TRS always spun. A Beta 300 4T always spun out and a couple other bikes struggled. My Beta 250 did the best, between the lower power and 9cs and 44t gearing made it work the best. So yes, it is not always about power. The Montesa riders were quite different levels, clubman, expert and Champ.   

  To get back to the OP real thoughts. He thought the Montesa had more inertia than the Sherco. Reality very good riders on a stock Montesa always hit lower on a splatter than on a similiar two stroke. That is coming from riders that have been there done that. Not from my opinion. I have witnessed this watching our top riders through the years. So yes, a stock bikes needs help if you are pushing your limits. (Not everyone is super human.)

 I also have seen Bou, Busto, Fuji, Frexia, and the most interesting Karlson make the Factory bikes just fly. Not on video, in sections that I have scored. Those bikes flat out run really well. Truly amazing riders. But I still believe the two stroke is better.   

[faussy]

19 hours ago, leosantanalg said:

why don't You and I just park the bike side by side , put in neutral and hold the throttle wide open to see what bike quits first??? #%^$&^*

What does that prove?

19 hours ago, leosantanalg said:

I m not the smartest and most knowledgeable in Trials 

My mistake, I guess it proves this

[leosantanalg]

sorry for all the trouble caused!! I bought the 300RR and was going to keep the sheco factory 300 to have a 2 stroke and 4 stroke simultaneously.

I ride a man made track and am not an expert but I m capable of basic techniques such zaps and splatters. 

it didn't take 1 month before I decided to get rid of the Sherco! Why?

I took both bikes to track few times and made sure to ride them back to back in the same obstacle... sometimes i had both running at the same time and one bike would idle while I did 5 zaps or splatters with the other one and kept taking turns...

my biggest obstacles in which I m comfortable for my skills is a 4feet 1inch high straight wooden wire spool and a 4 feet skidder tire buried half way which I aproack from the side (flat and undercut).

want to know the only reason I sold the Sherco?? I can get more lift, more height and more control on the 300 RR... It literally puzzles me when I hear that the bike is gutless and power delivery is not smooth! what am I missing?? how can you blame on technique and skill when I m riding them back to back? same rider! to be fully honest the Sherco had an advantage cuz is the one I was ridding the longest...

So, the list of advantages of the 4 stroke (personally to me) go on and on... but the straw that broke the camel's back: "engine Brake" after I started to get use to it, the 2 stroke served no purpose and I m heading for a pair of Montesas in 2019. I m not sure If I will build my own eventually or buy something already built. having 2 bikes is a must for me. always ready to go... if you riding and something breaks, the day is not over yet!  Thanks everyone for the input

 

 

[nhuskys]

53 minutes ago, leosantanalg said:

sorry for all the trouble caused!! I bought the 300RR and was going to keep the sheco factory 300 to have a 2 stroke and 4 stroke simultaneously.

I ride a man made track and am not an expert but I m capable of basic techniques such zaps and splatters. 

it didn't take 1 month before I decided to get rid of the Sherco! Why?

I took both bikes to track few times and made sure to ride them back to back in the same obstacle... sometimes i had both running at the same time and one bike would idle while I did 5 zaps or splatters with the other one and kept taking turns...

my biggest obstacles in which I m comfortable for my skills is a 4feet 1inch high straight wooden wire spool and a 4 feet skidder tire buried half way which I aproack from the side (flat and undercut).

want to know the only reason I sold the Sherco?? I can get more lift, more height and more control on the 300 RR... It literally puzzles me when I hear that the bike is gutless and power delivery is not smooth! what am I missing?? how can you blame on technique and skill when I m riding them back to back? same rider! to be fully honest the Sherco had an advantage cuz is the one I was ridding the longest...

So, the list of advantages of the 4 stroke (personally to me) go on and on... but the straw that broke the camel's back: "engine Brake" after I started to get use to it, the 2 stroke served no purpose and I m heading for a pair of Montesas in 2019. I m not sure If I will build my own eventually or buy something already built. having 2 bikes is a must for me. always ready to go... if you riding and something breaks, the day is not over yet!  Thanks everyone for the input

 

Quote

It still boils down to personal preference and possibly your technique, in that the 300R 4T just work better with its power delivery, clutch action and suspension.  I know a rider who went from 260RT, to 300RR 4T bikes and then finally a 300 2T bike.  His riding really improved on the 300 2T, with it being  way easier for him to do advanced moves on it. Does this make your experience invalid? No it doesn't, but shows what works for you, doesn't work the for all riders.  Be happy that you found a bike that works really well for you and buy a second one for back up. This doesn't mean that a Sherco 300 is junk though, it just doesn't work as well for you!

 

 

[leosantanalg]

4 hours ago, faussy said:

What does that prove?

My mistake, I guess it proves this

it proves the same point of having the beta 80 against your GG300, or should I say Nothing!!! the fact I was trying to figure why I think the 300rr has more power than my old Sherco 300sft is due to my very personal experience described in the thread!! and I am clueless. No mechanic experience whatsoever. however, I told you guys where the flywheel idea came from (from my friend -drifter) and it all make sense until debunked by a bunch of people here...  enjoy the GasGas.

[lineaway]

4 hours ago, leosantanalg said:

sorry for all the trouble caused!! I bought the 300RR and was going to keep the sheco factory 300 to have a 2 stroke and 4 stroke simultaneously.

I ride a man made track and am not an expert but I m capable of basic techniques such zaps and splatters. 

it didn't take 1 month before I decided to get rid of the Sherco! Why?

I took both bikes to track few times and made sure to ride them back to back in the same obstacle... sometimes i had both running at the same time and one bike would idle while I did 5 zaps or splatters with the other one and kept taking turns...

my biggest obstacles in which I m comfortable for my skills is a 4feet 1inch high straight wooden wire spool and a 4 feet skidder tire buried half way which I aproack from the side (flat and undercut).

want to know the only reason I sold the Sherco?? I can get more lift, more height and more control on the 300 RR... It literally puzzles me when I hear that the bike is gutless and power delivery is not smooth! what am I missing?? how can you blame on technique and skill when I m riding them back to back? same rider! to be fully honest the Sherco had an advantage cuz is the one I was ridding the longest...

So, the list of advantages of the 4 stroke (personally to me) go on and on... but the straw that broke the camel's back: "engine Brake" after I started to get use to it, the 2 stroke served no purpose and I m heading for a pair of Montesas in 2019. I m not sure If I will build my own eventually or buy something already built. having 2 bikes is a must for me. always ready to go... if you riding and something breaks, the day is not over yet!  Thanks everyone for the input

 

 

My son was about the same,went from a Sherco to a 300 Beta 4T. He absolutely loved the four stroke power and the engine braking. We also have 10 4rt’s at work that he rides quite well. Last summer he switched to a TRRS 300 RR. main reason was weight. If you hop all day the 4 strokes are just heavy. Good luck and have fun. The 300 is a great looking bike.

[section swept]

On 12/19/2018 at 7:02 PM, lineaway said:

My son was about the same,went from a Sherco to a 300 Beta 4T. He absolutely loved the four stroke power and the engine braking. We also have 10 4rt’s at work that he rides quite well. Last summer he switched to a TRRS 300 RR. main reason was weight. If you hop all day the 4 strokes are just heavy. Good luck and have fun. The 300 is a great looking bike.

10 4RT’S ar work! What line of work are you in....trials school....forest ranger....??‍♂️??