Motobene
Well-known member
I recently got past yet another prejudice: that auto clutches and trials bikes don't mix. I am now intrigued with the idea of converting my trials competition bike to the way all my other bikes have evolved: auto clutch, no clutch lever, no rear foot brake lever. Only throttle, one-finger hand brakes, and of course shifting. Very simple, easy, and I have found - for me anyway - superior in capability and the confidence that keep this old man going and competing well.
For top-level trials riders a manual clutch is a necessary, even as a big handful of throttle, spinning up the flywheels and releasing the clutch for big thrust impulses is necessary. Big jap-zaps, splatters, and even the 'yeeeuhhh! pulse-thrusting style many use. The French are especially strong in this clutch-slip culture and their event favor that culture:
The VAST majority of trials riders do not ride that way. My jap zaps and splatters are now small and don't need the big throttle mass clutch dumps. I'm not getting any younger and there is zero chance of me wanting to do the really big stuff again. It dawned on my at my last practice ride that the way I set up my off road bikes would definitely be an ADVANTAGE for me in trials. That is: The hydraulic clutch becomes the rear brake, there is no clutch lever or manual clutch of any kind, and gone is the entire foot brake. The only job for a foot is shifting, and feet are for dabbing without worry of loss of rear brake. My present battle is to stay calm and controlled and not fragment into spastic movements when too many situations and control movements overload old (or odd) brain. That's true even when on simple slopes:
But also true with logs, steps, drop-offs, etc.
My other bikes have:
I don't have a lot of videos to show every characteristic, but here's one that shows getting up a steep boondock trail. I'd never ridden it before, but knew that if I could not stand up all the way up that my Rekluse Radius CX EXP 3.0 would handle butt-weighted clutch slipping very well. Listen to the consistency.
Back in 2019, before I went auto clutch and changed my controls, I was happy with the Beta's manual clutch after modifying it:
But I was having issues stalling the bike, and bikes like it, in compromising places, and hurting myself. So I humbled myself and went auto clutch and had this day of discovery the summer of 2019:
From then on this system proved itself over and over and is now three of my bikes, including the latest big beast 701.
I currently know of two approaches to attaining an auto clutch on a trials bike. One is to send EFM a whole clutch assembly and have him make a ball-ramp-style auto clutch. I have never ridden a bike with an EFM clutch so it's a blank. I spoke to the owner and he states he can make an auto clutch for ANY bike. That's a pretty bold promise, all things considered.
The major trials brands except Beta and Hontesa have gone away from the conventional helical compression springs clutches. My TRS, like GasGas, Sherco, and Veritigo all have the diaphragm style and are typically physically smaller. Fitting in the centrifugal hardware and still having enough fiber and metal plates might be an issue?
A well known product to me are the older ball-ramp Rekluse auto clutches and their newer EXP (expansion pack) versions. I have three 3.0 version clutches. Their latest 4.0 version has refinements and looks quite good.
I know Rekluse don't make a clutch kit for any trials bike, but any trials bike that uses the same clutch plates as other bikes Rekluse does have kits for would make it possible for me to custom my own kit, as Rekluse would have the critical EXP and plates to fit the basket and the hub. I wonder if the Beta trials bike might share plates geometry with the RR and RR-S? If so, and with normal slave cylinder, the Beta trials bike might also be a candidate.
At present, I know the Montesa Cota could be a fit to existing Rekluse parts. The reason is the Cota clutch uses legacy clutch plates, a 22201- fiber plates and a 22321- steel plate. Rekluse makes an auto clutch for the CRF250F (22201-), so same EXP and fiber plates fit to the clutch basket, and they make one for the CRF450L and R (22321-), so same fit of the steel clutch plates to the hub. I was wrong about which models applied (see later post).
The most important requirement is the shape of the drive and driven plates and that determines the shape of the Rekluse expansion pack and their own thinner clutch plates.
The Cota is unfortunately weird in the use of a clutch-cover-based slave cylinder. That makes the clutch format 'bassackwards' at the pressure plate. Would that be an issue? Maybe not:
The CRFs have the clutch slave aspect (cam or hydraulic cylinder) on the left center case, thus 'forward-ackwards'
The CRF clutches are cable operated, which is strangely antique these days. Cable clutches make setting and holding Rekluse clutch-pack clearance at idle a bit more problematic.
I typically remove the cable and use only a threaded adjuster just upstream of the cam lever down at the engine. That gets rid of having the long elastic band (the cable) under constant tension,
from varying the clutch-pack clearance with steering degrees (which affects cable tension), and cable temperature, which also affects cable tension.
The Cota's clutch is hydraulic, which is good.
...so the clearance could be set by machining in a setscrew in the center of the cover to push on the slave cylinder piston backside.
That's how the Rekluse slave cylinder works:
Given I don't need anything hydraulic a simple setscrew would work in a Cota as I don't have to seal brake fluid or mineral oil.
I will talk to EFM about braving their auto clutch for my TRS.
Buy a cheap used Beta to try that angle with Rekluse?
I think I'd be more inclined to buy a NEW Cota just to do something new and work getting an EXP 4.0 to fit the HRC motor's clutch. Been gaining some interest in these heavy sleds anyway
For top-level trials riders a manual clutch is a necessary, even as a big handful of throttle, spinning up the flywheels and releasing the clutch for big thrust impulses is necessary. Big jap-zaps, splatters, and even the 'yeeeuhhh! pulse-thrusting style many use. The French are especially strong in this clutch-slip culture and their event favor that culture:
The VAST majority of trials riders do not ride that way. My jap zaps and splatters are now small and don't need the big throttle mass clutch dumps. I'm not getting any younger and there is zero chance of me wanting to do the really big stuff again. It dawned on my at my last practice ride that the way I set up my off road bikes would definitely be an ADVANTAGE for me in trials. That is: The hydraulic clutch becomes the rear brake, there is no clutch lever or manual clutch of any kind, and gone is the entire foot brake. The only job for a foot is shifting, and feet are for dabbing without worry of loss of rear brake. My present battle is to stay calm and controlled and not fragment into spastic movements when too many situations and control movements overload old (or odd) brain. That's true even when on simple slopes:
TEMP - buffalodream
This video hosted by SmugMug; your photos and videos look better here.
buffalodream.smugmug.com
But also true with logs, steps, drop-offs, etc.
My other bikes have:
- Brakes always available, instantly, all the time, no matter where the brake foot is (reduction in sphincter puckering)
- Clutch control that is steadier and easier to meter by throttle/rpm than I can with the combo of manual clutch and throttle
- A rear brake that works like a clutch and in the same timing as a clutch hop and pop up on things from a standstill
I don't have a lot of videos to show every characteristic, but here's one that shows getting up a steep boondock trail. I'd never ridden it before, but knew that if I could not stand up all the way up that my Rekluse Radius CX EXP 3.0 would handle butt-weighted clutch slipping very well. Listen to the consistency.
240116 West Mesa 390 + Rusty 300 - buffalodream
This video hosted by SmugMug; your photos and videos look better here.
buffalodream.smugmug.com
Back in 2019, before I went auto clutch and changed my controls, I was happy with the Beta's manual clutch after modifying it:
2019 Beta 390 RR-S - buffalodream
This video hosted by SmugMug; your photos and videos look better here.
buffalodream.smugmug.com
But I was having issues stalling the bike, and bikes like it, in compromising places, and hurting myself. So I humbled myself and went auto clutch and had this day of discovery the summer of 2019:
2019 Beta 390 RR-S - buffalodream
This video hosted by SmugMug; your photos and videos look better here.
buffalodream.smugmug.com
From then on this system proved itself over and over and is now three of my bikes, including the latest big beast 701.
I currently know of two approaches to attaining an auto clutch on a trials bike. One is to send EFM a whole clutch assembly and have him make a ball-ramp-style auto clutch. I have never ridden a bike with an EFM clutch so it's a blank. I spoke to the owner and he states he can make an auto clutch for ANY bike. That's a pretty bold promise, all things considered.
The major trials brands except Beta and Hontesa have gone away from the conventional helical compression springs clutches. My TRS, like GasGas, Sherco, and Veritigo all have the diaphragm style and are typically physically smaller. Fitting in the centrifugal hardware and still having enough fiber and metal plates might be an issue?
Dirt Bike Clutches for Major Brands: Honda, Kawasaki, KTM, Suzuki, Yamaha
Find dirt bike clutches for all major models at $745. Call for details on older models and custom brake systems. Fast, expert support available!
efmautoclutch.com
A well known product to me are the older ball-ramp Rekluse auto clutches and their newer EXP (expansion pack) versions. I have three 3.0 version clutches. Their latest 4.0 version has refinements and looks quite good.
I know Rekluse don't make a clutch kit for any trials bike, but any trials bike that uses the same clutch plates as other bikes Rekluse does have kits for would make it possible for me to custom my own kit, as Rekluse would have the critical EXP and plates to fit the basket and the hub. I wonder if the Beta trials bike might share plates geometry with the RR and RR-S? If so, and with normal slave cylinder, the Beta trials bike might also be a candidate.
At present, I know the Montesa Cota could be a fit to existing Rekluse parts. The reason is the Cota clutch uses legacy clutch plates, a 22201- fiber plates and a 22321- steel plate. Rekluse makes an auto clutch for the CRF250F (22201-), so same EXP and fiber plates fit to the clutch basket, and they make one for the CRF450L and R (22321-), so same fit of the steel clutch plates to the hub. I was wrong about which models applied (see later post).
The most important requirement is the shape of the drive and driven plates and that determines the shape of the Rekluse expansion pack and their own thinner clutch plates.
The Cota is unfortunately weird in the use of a clutch-cover-based slave cylinder. That makes the clutch format 'bassackwards' at the pressure plate. Would that be an issue? Maybe not:
The CRFs have the clutch slave aspect (cam or hydraulic cylinder) on the left center case, thus 'forward-ackwards'
The CRF clutches are cable operated, which is strangely antique these days. Cable clutches make setting and holding Rekluse clutch-pack clearance at idle a bit more problematic.
I typically remove the cable and use only a threaded adjuster just upstream of the cam lever down at the engine. That gets rid of having the long elastic band (the cable) under constant tension,
from varying the clutch-pack clearance with steering degrees (which affects cable tension), and cable temperature, which also affects cable tension.
The Cota's clutch is hydraulic, which is good.
...so the clearance could be set by machining in a setscrew in the center of the cover to push on the slave cylinder piston backside.
That's how the Rekluse slave cylinder works:
Given I don't need anything hydraulic a simple setscrew would work in a Cota as I don't have to seal brake fluid or mineral oil.
I will talk to EFM about braving their auto clutch for my TRS.
Buy a cheap used Beta to try that angle with Rekluse?
I think I'd be more inclined to buy a NEW Cota just to do something new and work getting an EXP 4.0 to fit the HRC motor's clutch. Been gaining some interest in these heavy sleds anyway
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