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clutch actuator arm extension

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for those who extended the clutch actuator deal at the motor end, is it as simple and cutting it and extending it? how far did you extend it? any before/after pics? hopefully the new clutch cable will solve most of my problems. thanks

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You can lengthen the clutch arm for an easier pull. I got the idea from a post by Towlieee on TT and it worked very well. The poster welded a 3/4" splice into the clutch arm but for me it was easier to bolt on an extension to the arm, that way I could easily go back to stock. Here is a link to Towliee’s thread: http://www.thumpertalk.com/forum/showthread.php?t=784686&highlight=clutch+mod

Sorry I don't have a pic but here is a description that you can use with the pics in the above link, I hope is understandable:

I chose a bolt on extension so I could easily return to stock if I didn’t like the results. Also I was able to do the bolt on without removing the clutch arm/shaft from the side case, which is a PITA. I drilled out the rivet holding the cable clip to the arm and took it to ACE hardware and purchased two metric bolts and lock nuts to suit, I think 5mm). I then used a 3/4" x 2" piece of flat stock (Home Depot) to replicate the end of the the clutch arm with a 3/4" extension, this fit to the underside of the arm and extended 3/4" beyond the end of the clutch arm. I contoured the outer end to duplicate the radius on the end of the clutch arm, and the inner end to fit the joggle in the stock clutch arm. I then clamped it to the under side of the clutch arm and used the existing clip hole to drill the extension, fastened it with a 5mm bolt. I then drilled a hole thru both for a 1/8" SS rivet between the existing cable clip hole and the dogleg bend in the lever (not enough room for another bolt hole). Next I installed the cable clip to the hole in the end of the flat stock that was 3/4" away from the original cable clip hole. And then used a tapered drift bar to re align cable bracket to the new hole. 40% reduction in clutch pull!!

Cable - Honda #22870-KT0-670 $20.78 MotionPro #02-0055 $14.70

Since I've added extensions to other engines and also put an ASV lever on one bike with the cable in the easy pull position for more reduction, almost one finger pull but I use two.

My benchmark for clutch action and pull is my Montessa 315R which has a hydraulic clutch with easy pull and a long smooth range of engagement. One finger pull with usable disengagement with the lever against my other fingers, when stopped I use two fingers and pull the lever to the bars.

My XR200 with shimmed clutch springs is now an easy two finger pull for usable disengagement with the lever against my other fingers, a big improvement compared to stock.

Last item; move the lever in on the handlebar as far as you can so you grip the end of the lever for a lighter pull (also reduces risk of lever damage).

Hope this helps

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howdy-

for those who extended the clutch actuator deal at the motor end, is it as simple and cutting it and extending it?

nope- it's simpler! Like Chuck, I wanted to be able to go back to stock- but on my XR4 I did not want to modify the stock arm, not even to drill a hole. Making this extension doesn't require anything but a small chunk of "U" steel (kinda like C-channel iron but has rolled edges), a file, a drill, and an angle grinder. I also realigned the bottom cable holder, similar to what Chuck did. If you had everything together, you could do it in half an hour.

But get a new cable first, otherwise you're just treating the symptom.

A picture is worth a 1000 words (and about a thousand words below it)...

clutcharmmod.jpg

Clutch feel- I'm kinda weird about this. I do not like “floppy” levers but I demand a very smooth clutch with a progressive feel (hydraulic clutches fall somewhat short here, in my opinion). To meet both of these opposing conditions, I keep my cable well lubricated and routed correctly (no big surprise there) but I also put HDPE bearings on my clutch lever pivot bolt. I make these low tech bearings from milk jugs (uh, empty) using a hole punch (6mm on the bolt bottom and 8mm for the top, IIRC). Actually, most of the time I just use one on the bottom of the lever (6mm) unless I have a mismatch of perch-versus-lever brands. Anyway, its nice to have a lever with no up-and-down play and also be buttery-smooth. To further my “butter” clutch research, I have built, but have yet to install, an add-on extension to my actuating arm to increase the leverage about 25-30%. My clutch is so good right now I don't wanna screw with it. BTW, I consider myself to be very easy on clutches- my XR400 one is 11 years old, and it is due for new plates, but the action and hookup are still good. If I need a new basket, I'm considering Barnett- I like the idea of stainless steel inserts on the aluminum hub (Anybody have any real-life experience?). In my two-stroke days I was a member of the clutch-of-the-month club. But the power delivery is milder now too on the XR- because, although Hp and weight are close to my '75 MX250 Yamaha, the power is more linear. [Later: hell, my friction plates were still in spec (~2.97mm) but my springs were close (~41.84mm which is too close to the 41.6mm minimum; 43mm when new)]

[June '09] Well, I finally added the extension to my clutch actuating arm. It ended up being 19mm long, giving it about a 45% increase in leverage (the stock arm is about 42-43mm) and of course, the same percentage loss in motion range. I did this because I figured I could always make it shorter (with certain limitations) if things did not work out. With that in mind, I did not rivet the extension to the actuating arm yet, but instead I used a button head allen screw with a nut to hold it on. This way I can easily remove and modify it without taking the clutch cover off. I'll probably rivet it once I'm satisfied with the performance. Also the 19mm extension was just a bit long- when installing the clutch cover, it caused a little interference when passing under the header before the cable was connected. But once the clutch cover was wiggled on, whoo-boy! Is this thing smooth or what! I'll give a more detailed report when I've got enough hours with it to make good observations. At the moment: A+ .

[september '09- this mod is great; I ain't never going back! Swear-to-god, the KTM guys are jealous.]

And I learned a new clutch maintenance trick from a friend: put all your steel clutch plates in a stack and look for light coming from between any one of them- this will tell you if you got a warped plate(s). I've always used the plate-on-the-sheet-of-glass trick.

Your XR400 throttle cables may be wearing on your oil cooler. The stock routing of these cables brings them to the left side of the frame- and sometimes they can rub on the oil cooler fittings, wearing the sheaths. If so, take a vinyl hose, 4 inches long, cut it in a spiral and then thread it on to the affected

good luck.

later,

Jack

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Hey-

I was cleaning up my computer's file system and I found a couple more images that might help the clutch arm extension design:

this chunk was first cut down the middle...

extensionraw2.jpg

end view

extensionraw.jpg

final product after drilling and shaping (and paint)- ready to install.

clutcharmextension.jpg

later,

Jack

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My XL185S I Rebuilt the engine and have it back in the frame and I cannot get the clutch cable to reach the clutch actuator arm. It's almost as if the actuator has some kind of interference. The only way I can get the cable to link with the actuator arm is if I loosen the cable at the clutch lever. What am I doing wrong? See photos below. Thanks

ImageUploadedByThumper Talk1435904627.114456.jpgImageUploadedByThumper Talk1435904750.742617.jpg

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You need to loosen the lower adjustment just above the actuator arm by loosening the lock nut, then the main adjuster.

It could be easier to remove the clutch lever pivot bolt, fit cable to arm and lever then twist the lever into place and fit pivot bolt.

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My XL185S I Rebuilt the engine and have it back in the frame and I cannot get the clutch cable to reach the clutch actuator arm. It's almost as if the actuator has some kind of interference. The only way I can get the cable to link with the actuator arm is if I loosen the cable at the clutch lever. What am I doing wrong? See photos below. Thanks

attachicon.gifImageUploadedByThumper Talk1435904627.114456.jpgattachicon.gifImageUploadedByThumper Talk1435904750.742617.jpg

 

Put it back like in picture #1. Then grab the lever at the engine with a pair of vise grips and turn it back far enough to engage the cable. Then adjust cable so you have slight freeplay travel at the lever on the handlebars.

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Thanks for the advice. I don't think I'm going to force the lever with vice grips just yet, but I will let you know what happens tonight when I try adjusting the lower nuts.

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Glad to see you got it reconnected, but FYI, you're not forcing the lever by using vise grips, you're turning it in the normal direction. Any resistance felt is just the clutch pack being slightly disengaged as you turn the lever enough to engage with the cable end.

 

I couldn't tell in the video if you had any clutch lever freeplay. If you didn't adjust it to have a little play, then your clutch may be constantly slipping, creating more heat, wearing out the fiber discs prematurely and contaminating your oil faster. As the clutch and engine heat up, clutch parts expand, so you need a little free play in the lever to allow for that.

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Thanks trailryder. I didn't want to mar up the lever with vice grips. I have since adjusted it. My buddy lets know I need to do that also. I am grateful for thumper talk. Everyone is able to help me and keep this build from stalling out. Video below shows free play

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Mar up the lever? I guess you're not understanding. Grab the lever like in the pics. You could even use an open end wrench or Cresent wrench.

Lever 1.jpg

lever 2.jpg

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