4RT Clutch Actuation?

[mcman56]

18 hours ago, Tr1AL said:

The 4RT 301RR makes  a pathetic 16.3 HP , 1 HP more than a VERTIGO 125   but the 301RR puts out 15.1 ft/lbs torque  , where as the VERTIGO 125 makes 8.8 ft/lbs . With that much torque output of the 301 it may be better leaving it with the stock clutch spring set up.

4RT 260 makes 15.6 HP and 13.4 ft/lbs torque

Are HP and torque numbers available for the standard Beta 300 4t, maybe with rpm numbers?  I have one of those too.  In a tight section, the Montesa feels much more powerful so I need to use very little throttle.  I thought it was overall more powerful.  However, the other day I took it to some open trails with good size hills.  There it feels similar to the Beta.  I wonder if there is a real power difference or if the fuel injection just makes it more responsive.  

[lemur]

The problem you are noting with the Beta 4T throttle response is they fitted the bike with a CV carburetor. Vacuum operated carburetors rob engine intake vacuum pressure to operate the carburetor negatively effecting both the throttle response and the engine performance, in PGM-Fi fuel systems 100% of the engine vacuum pressure is dedicated to intake of air & fuel, Fi does not exhibit the throttle lag and occasional misfires inherent to the CV carbs normal operation.  

[mcman56]

On 11/15/2025 at 5:24 AM, lineaway said:

The plate holds the springs straight. They other wise rub

on the towers. The springs are much lighter. Available from Webike.

Why do they rub?  Do the springs have a smaller inside diameter?  Is the plate just slightly thicker with the groove to center the springs.

[lemur]

Want to know what will happen after you put lighter pressure plate springs then required in your clutch <- it's going to slip in high gear ranges, same as if you leave 2 of the 6 springs out.  

Rhetorical question but dimpled steel clutch plates in a wet clutch leaves more space for oil between the plates, do you believe that scenario will make the clutch grab stronger or slip easier 🤔 and with dimpled plates having more oil between the plates and less surface area contacting the friction plates, will that make your clutch feel any lighter to pull at the lever, I think not.  Throw in some lighter springs and you have a formula for inducing more clutch slip.  

Edited 4 hours ago by lemur

[jrsunt]

I also think it would slip when removing springs.
The 4rt clutch is quite grabby compared to other models, Elf and light gear oils emphasise the issue more so. The early ones with the small master cylinder were particularly bad.

Setting the lever up correctly is quite important and the dimpled plates really do help, much more progressive and will not slip, ever. 
The Mitani clutch pack is awesome, starts in 1st gear and is quite a bit lighter…. expensive too, but a good investment.
I believe there are titanium springs for these, not sure if they give a different feel or are just purely for weight saving