Does anyone have the above data? How much weigh the fly wheels of 2rt and 4rt it by brand? 

Can't compare on weight alone as diameter is a major factor. 

How about diameter then? Who has it bigger? 

Depends on other things such as crankshaft weight etc.

Ross is correct, it's not just weight.

Actually, it's not just diameter either, it's actually 'moment of inertia' that matters, see here clicky thing

How do you imagine this influences how you keep your feet up?

4 minutes ago, gii said:

Ross is correct, it's not just weight.

Actually, it's not just diameter either, it's actually 'moment of inertia' that matters, see here clicky thing

How do you imagine this influences how you keep your feet up?

It doesn’t.  But it’s know that more torque will come from more inertia. So, whichever bike can generate such with have a bigger punch correct? When you go for a splatter and accelerate the fly wheel clutch fully Off and then pop it, more inertia = more launch! Correct? 

Sort of, but in addition to my Mont 4RT, I have 2 x Matchless rigid trials bikes, both have the same bore and stroke and similar frame dimensions, the 1941 bike has much lighter flywheels than the 1952 bike and is the one I prefer for modern 'pre65' trials, it revs quicker and feels 'punchier'. the later bike with the heavy flywheels is really, really great for hill climbs though.

I guess you must be riding different types of sections to us if it matter so much

 You need to spend some dollars if you want a stock 4rt to have some punch. https://www.termignoni.it/en/product-category/montesa-en/

None of the good riders on Montesa have stock machines.

 Also most of the top riders have a stronger clutch to create a quicker inertia.

Edited December 17, 20187 yr by lineaway

I did not realise that the 300rr was that gutless that an amateur rider would need to to tune it up.........are we talking about the same bike as this one  https://youtu.be/Jr3w9J_qRGU

 

 

Edit https://youtu.be/qRdFWumITQw?t=7m56s   sounds pretty much the same to me.

 

 

Edited December 17, 20187 yr by oni nou

 Yep. The stock one does not sound like that one. That is why the sound is covered up!

So the stock 300rr  has less punch than an amateur rider needs then?  sounds preposterous to me.

Edited December 17, 20187 yr by oni nou

Unless of course he weighs 40 stone.

 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.

11 minutes ago, 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.

Yes of course I am aware of the disparity between the 2T power unit and the 4T power unit as is shown in the junior champs where kids  can ride the 4rt against 125 2t's  but really I mean seriously he does not need  more punch as an amateur and this could be easily proven if we got Toni Bou to come and ride his standard 300rr bike in the expert class in a USA national against Pat Smage on a 300 2t Sherco .......my moneys on Bou winning on his gutless 300rr.

Edited December 17, 20187 yr by oni nou

43 minutes ago, oni nou said:

I did not realise that the 300rr was that gutless that an amateur rider would need to to tune it up.........are we talking about the same bike as this one  https://youtu.be/Jr3w9J_qRGU

That’s what I think!! In the USA everyone seems to believe that this bike has no guts. I think it has much more than my previous bike: a 2018 300sherco factory.