Auto-Clutch Wars

[woodsripper]

I have been looking into an auto-clutch for my 400 EXC. There are three on the market that I am aware of; RevLoc at $995, EFM-Billet at $500, and Z-Start at $359. I think the Z-Start is only for the Honda CRF 450.

I called both RevLoc (talked to Dave) and EFM-Billet (talked to Garry) and both guys claim their clutch is better. Here are the facts from my conversions with these guys:

1. RevLoc send you ready to use clutch, charges a $400 core exchange, and then credits your $400 when you send them your basket and inner hub. They will also upgrade '00 and '01 bikes to the '02 style inner hub. EFM-Billet requires that you send them your clutch parts and they modify the inner hub and send you back the autoclutch in about a week.

2. Both clutches require a new inner hub if you want to restore the clutch back to original. I am not sure of the price, but both thought they were about $150 from KTM.

3. RevLoc has made a total of 700 clutches, about 70 were for KTMs. EFM has made about 350 clutches, about 50 were for KTMs.

4. RevLoc is made of 7071 Al and uses Tungsten carbide balls. According to Dave, this is an advantage and the reason why their clutch is better.

5. EFM uses 6061 Al and uses relatively common hardened steel ball bearings. Garry says that his design works with these materials and does not need the hard materials that RevLoc and Z-start use. According to Garry, the other manufacture's designs are prone to galling and deformation and require the hard materials to provide reasonable life. (RevLoc has slots or pockets for balls to ride in, EFM has flat ramps that the balls ride in). I have not seen any design details of either clutch, so I have to take this info at face value until I know differently.

6. RevLoc states that they have engineered their product from scratch. EFM says that they simply copied the proven design used in ATV autoclutches and applied it to the dirt bike clutch. EFM believes their ATV-copy design, which lasts forever on ATVs (which weigh 2x of a dirt bike), will last for years.

7. EFM clutch has 0.140" of travel and should not need any adjustment throughout the life of the clutch plates. The RevLoc has approximately 0.040" of travel and will require adjustment as the clutch plates wear according to Garry.

8. Garry of EFM has been making autoclutches for his own use and for go-karts since 1993. He decided to get into the autoclutch business after he saw that RevLoc was being successful with their design.

9. Both designs allow the use of the clutch lever to "fan" the clutch and to do motocross starts. There is a limit at which you cannot overcome the force of the balls. According to both, you can use the clutch to get the bike back into the meat of the power.


I like the general idea of the autoclutch because I tend to wear myself-out during a tight harescramble with my 400. I have read nothing but positive reviews of any autoclutch (Revloc, EFM, Z-Start) although I do not know anyone who personally has one.


At this point, I am leaning towards the EFM for two reasons:

1) It is half the price. I can live with $500 experiment but I am not sure if I can live with losing $1000 (actually the costs are $650 and $1150, including a new inner hub to get my OEM clutch back).

and

2) I like the idea that EFM is an ATV clutch copy.


Has anyone tried an autoclutch? What are your experiences?

 

[KDXfile]

I thinking about the EMF also. What I understood, from talking with Garry, is that you can use the same basket if you want to go back the stock.

 

[DirtRydin]

Why would you want one?

 

[DirtRydin]

I had an automatic quad and hated it!

 

[KDXfile]

The main reason for me is for tight enduros. When you're having to pull the clutch in every 10-20' to navigate a turn or to keep from stalling the engine.

 

[jaliveto]

Does EMF have a websight. How about z-start. Do you guys know how to contact them?

 

[KDXfile]

EFM has a web site at www.efm-billet.com

 

[flynbryan]

I just maybe one of those people that doesnt like progress,but I dont like the thought of an auto clutch. I've been reading various posts about the auto clutches and I fully agree with the obvious advantages of the auto clutches. I just feel almost like its "cheating" (funny as it sounds) Mastering a manual clutch has aways been part of motorcycle riding in my opinion. Also i have yet to hear anyone say anything about if you need to loft the front end in a hurry. How responsive is the auto clutches? Just my two cents and I'm sure that they are plenty that will disagree. :)

 

[steven lewis]

I have a REVLOC clutch for sale ,fits 2001 KTM RFS 400 or 520 ,will make someone a good deal. Only has about 250 mile on it.The clutches work very well,with very little time to adjust.I'f interested I can be reached a LLEWIS3066@AOL.COM

 

[woodsguy2000]

I agree with flynbryan, part of the riding experience is learning and trying to master all aspects of riding. Mastering a clutch takes time.
But I know there are people who love them.
I have ridden one and it was on a YZF and it had no problem lifting the front tire. Did not try it in a panic situation, got to lift now type thing but it would come up on demand. Thought the bike felt like a quad in that it was just a little sluggish at first. Could be me, but I will stick with a regular clutch.

Rob

 

[tiller]

I disagree. It is just making your bike the best it can be for the conditions you ride in. Guess some people could look at the suspension systems that we now have as being like cheating compared to the 4" travel forks and shocks of the sixties. How about electric starters? Stall on a hill next to some guy on a YZF and hit the button and take off. While he sits there kicking until he is exhausted. I don't call it cheating, I call it progress!

 

[steven lewis]

I tried a revloc do to problems with my hands ,I found it worked very well,in all situations. It took almost no adjustment time.I fill it would make a novice rider a better rider . But I found it took away an element of fun that makes dirt riding what it is for me. The revloc is a fine piece of equipment and it could be just the ticket for you, I'll clutch it and rail.
Ride Hard
Steve

 

[KTM Pete]

I bought the first Revloc made for a KTM 2-stroke('00300EXC) last spring. Also bought due to carpal tunnel. My left hand doesn't fall asleep anymore and I'm not as tired during an enduro. tried it out at MX and didn't like it as much- starts were poor (my inexperience with the clutch too)and didn't slip the clutch well when I needed it. I notice more flywheel effect from the increased weight- great for enduros and HS. Dave at Revloc says to now take out the inner row of ball bearings- lightens it up and they're not necessary for clutch actuation.
After adjusting the clutch and getting used to it more I can slip the clutch for revs and the bike gives me power whenever I need it. I have not had any wear issues or problems with the clutch. I learn more every time I ride it because the lack of stalling allows for different braking techniques. I am also relearning snotty hills, roots-very differentmethods.
I do think I am faster because of it-no stalling, less tired later in the race, some obstacles are easier.

 

[jaliveto]

woodsripper- have you gotten your auto clutch. What did you buy. How does it work. Did it go in easy?

 

[Doc]

Jeff Ferdette was using an automatic clutch and experienced a transmission failure due to the sudden harsh engagement. However, when he was first using it he thought it was great.

 

[Enduro_Nut]

It sounds like the issue Gary was speaking about regarding hard hook up, his clutch has more slippage so it won't break the tranny. I'm going with the EFM on my GasGas 300 and can't wait!
To some degree Woodsguy 2000 has a point, part of the challenge is proper clutch control - BUT I'm too lazy and want to concentrate on gaining more speed with a "handicap"!! :thumb:

 

[Rick H]

Revlok sent updates to me to modify the clutch to give it more give. It worked great before and I can't really tell the difference after (maybe my tranny can though?)

 

[beer_stud_76]

as for lifting the front wheel, the clutch lever is still there on both the EMF and revloc and can be used as per tradition for extra power.


jeremiah

 

[Scoott]

I installed a rev-loc on my 520 mxc last summer and I'm working on getting a efm clutch for my 03 250 sx. I am " digitally challenged" (missing fingers on both hands) and the rev-loc has been the answer that I've searched for for my whole racing career(25+ years). I tried the air and water cooled Husky auto's, but I hated the coasting and lag in response( unless you drug the brake ALL of the time!).I had a 93 300 that I rigged an extra clutch cable that ran to the rear brake pedal and released the clutch when I applied the brake. That had issues though, no brake dragging, had to remember to pin the gas before releasing the brake, etc. Then I got the 520 mxc with electric start, but it doesn't always fire right back to life when you stall in the heat of the battle.
The rev-loc is a wonderful tool. If you don't need it, you hardly are aware of it's presence,but when things get tight or ugly it shines. Tight trails, mud,even rocks are much easier to negotiate with the rev-loc. Gearing is less critical because of the anti-stall.
The GP races I put on have new sections added that are much tighter then in the past solely because they're more fun for me to ride. I can charge corners harder without fear of stalling and I'm even learning to brake slide.All skill levels can benefit from the auto-clutch if they have any kind of issues with the clutch. I am a 40 expert , but I have let rank beginners to pro's ride the 520 with good results.
Like the happy button on my 520, I can't imagine riding without one. (Yah, I know,the 03 250 doesn't have a button. That's why it's getting a auto-clutch).

01 520mxc
03 250sx
Eddieville motorsports
Starvation Ridge
Goodnoe Hills

 

[BBD]

I just put a Z start on a customers bike, CRF 450 ,03 model. Riding the bike in the woods behind our shop was as easy as can be. the set-up of the Z start was per instuctions and left in stock configuration from Z start. The bike would pull the front up to clear whatever you need to. It felt like the stock bike on slowing down until you reached the stall speed of the system then it would just idle or coast. This bike was very easy to ride for anyone.

 

[RakO]

Originally posted by BBD
I just put a Z start on a customers bike, CRF 450 ,03 model. Riding the bike in the woods behind our shop was as easy as can be. the set-up of the Z start was per instuctions and left in stock configuration from Z start. The bike would pull the front up to clear whatever you need to. It felt like the stock bike on slowing down until you reached the stall speed of the system then it would just idle or coast. This bike was very easy to ride for anyone.

If you still have the "engine braking " effect it si sure that it is a + . Many 4 strokers like this effect,it is sade that the manufacturers are trying to avoid this "wonderfull" effect ..... OK it is my opinion :-)
RakO

 

[KiwiBird]

I've watched this debate with some interest lately, however an incident in the weekend has sold me OFF the idea.

My buddy lightly seized his CR500 with RevLoc. It had lost some compression and could not be started by kicking it but I think it could have started with a bump down the steep hills we were on. Unfortunately you can't bump start a bike with a RevLoc, so that was that - we rode out double and he had to come back the next day and get his bike.

 

[beer_stud_76]

kiwi -

thats sounds like a real good reason to not put one on a CR500


jeremiah

 

[James Dean]

Originally posted by Kiwi Bird
Unfortunately you can't bump start a bike with a RevLoc,

You CAN bump start with the EFM in an emergency situation. The clutch cover needs to be pulled off and 2 set screws inserted into the pressure plate. This will lock the clutch up in an emergency, like broken kick-start or dead battery without a kick-start(DRZ's). It's called the "stranded mode."

James

 

[dpdiehl]

Enduro_nut, I have a GG300XC with one of Garry's clutchs. you will love it!