Gas Gas adjustable clutch advice

[ksv]

I've been riding my 2020 300 GP for a while now and love it but I am struggling to adapt to the clutch. It's very light but the lever throw is quite long compared to previous bikes I've owned. 

I'm aware they have a 3 stage adjustable clutch but I can't seem to find much information on them or if adjusting it will have the desired effect. Basically I want a shorter lever throw and the bite point to be more instant.

Can anyone shed some light on this and what the 3 different positions do?

Cheers

Kirk

[arnoux]

The 3 different positions adjust the amount of preload on the Bellville spring. You want to be in the greatest pre-load position, so clamping down on the plates firmer.

The 2020 has a 1.2mm Bellville. Earlier bikes had 1.5mm and even 1.7mm on the first years of the Pro motor. So clamped harder, and released harder, but at the slight expense of a stiffer lever. The 2020 is very light.

Check you combined plate height. You want the 5 plates to be up around 9.98 - 10mm, this gives you the maximum pre-load on the spring.

See how you go with that, and if you want it more aggressive get a 1.5mm Bellville to try.

[ksv]

Thanks arnoux, much appreciated!

I presume I will need some very accurate digital calipers to get that level of accuracy on the plate height. 

This might be a stupid question but what do I do if the plate height is not in that range? New clutch plates? The bike has only been ridden a handful of times so I am guessing it will be fine for a while. But is this something I should be measuring periodically to maintain the proper clutch tolerances? If they are out of tolerance after say a years riding would it be new clutch plates to sort?

Cheers

[d2w]

This is likely equivalent to the OEM unit in your GG: https://www.splatshop.co.uk/xiu-rdi-adjustable-spring-clutch-support-plate.html

[the dabster]

So how do you adjust the ring with three numbered options and what effect does it have overall?

[ksv]

So I took the clutch cover off yesterday and the clutch was in position 2 from standard. So I've moved it to position 3 to see if that helps. I'll report back once I've tried it on a ride.

[lineaway]

The oil also makes a difference on a quick bite or not. That was why most of us used atf on the pro clutch. I sold a 2004 pro to a guy. He had me resell it as he bought a new Montesa. I could hardly ride the thing, the clutch was so slow. I called him and asked what he had done to the bike. All he did was change to Amsoil.

[ossa68]

Sostituisci olio con elf htx 740 75w olio di serie non è nulla di speciale          https://www.splatshop.co.uk/elf-htx-740-gear-box-oil-75w-1ltr-montesa-315-4rt.html

Replace oil with elf htx 740 75w stock oil is nothing special

[peterb]

The 3 position belville spring compression ring are likely made by the same company, for GG and Vertigo. The softest position is on 1, then 2 and 3 are progressively harder by 0.10mm in each position, such that position 2 is machined by 0.10mm, then position 3 machined deeper by 0.20mm to allow more compression on the spring. Position 3 would give a stronger spring tension and a shorter travel from clutch biting point. Bye, Peter B.

[smarty156]

Quick question re the Xiu-RDI adjustable clutch ring. I have one for my 2014 TXT Pro Racing which I've not yet fitted (just has the original standard non-adjustable one) but it does have Xiu-RDI kevlar clutch plates.

The clutch has been working great (light lever, good control, never need to adjust the bite point etc) but I've now noticed it's slipping when in 5th or 6th (possibly in lower gears but not so easy to tell).

Presumably this is due to the plates wearing and the clutch pack now being too thin. On the description of the Xiu-RDI adjustable clutch it says position 1 is the same as standard (for new clutch plates). As the plates wear you can then move to position 2 then position 3. This is the quote:

"Recommended use:
A.-With new pads you can start with position num.1 or 2, depending your preferences.
B.-After some working time, pads will be adapted and will be thinner. Then you can choose a higher number, until position num.3."

Now, I can understand that if the clutch pack is too thin then the pressure exerted on it by the belville spring will be less and it will start slipping. Presumably (I need to take it apart still) the finger height will now also be too high. What I don't understand is how the position 2 or 3 will impact finger height, if at all. I get that it will exert more force onto the spring, hopefully bringing it back to the same force as when new but won't the finger height still be too high? and if so will that still cause clutch slip issues? Or does it not matter in this case?

What I don't want to do is go to position 2 then find at the next trial (this Sunday) that it's still the same.

Cheers.

[lineaway]

 Either buy new plates or you could get the original spring, but the pull would be much heavier.  From our online distibutor down under. Earlier bikes had 1.5mm and even 1.7mm on the first years of the Pro motor.

[smarty156]

For anyone that may be interested I fitted the adjustable ring and moved it to position 2. Clutch slip has completely gone and clutch is as light as it was originally.

Edited May 16, 2022 by smarty156

[drca]

I usually play with the clutch pack thickness until I get the feel I want at the lever and engagement speed that works for me.  Best way to adjust clutch pack thickness is to swap steel plates with different thickness.  you can get them from Splat Shop: https://www.splatshop.co.uk/dp-gasgas-pro-clutch-steel-plates.html

Their page even shows the recommended thickness range for each model year.