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Reduce CRF100 clutch pull (spring force is too much!)

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Hi, Just got a 2008 CRF 100.  The clutch pull is at least twice as hard as my 2007 CRF 250X.  The cable is well lubed, and smooth.  It is the spring pressure that's too much.  I need to teach a new rider to use a clutch and I don't think she can pull it more than a few times in a whole day.  Why in the world is the pull so hard on a beginner bike?

 

I know what worn cables pull like, you can tell it's cable friction when the pull is not the same going in and out.  But a new cable will has to help some, will do that if need more.

 

Does anybody have any tricks to reduce the pull?  Are there mods you can do to the actuator inside the clutch case?  It looks like the external lever arm can be extended about 20% but that's not much help.

 

Someone must have solved this.  I can't be the first dad who noticed this.

 

edit----- Found THIS Thumpertalk thread with some answers but no responses.

Edited by WA_trail_rider

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Two ideas that I have used:

The MSR Raptor lever/perch has three cable attach points, one is stock and one is easy pull.

Add an extension to the engine clutch arm. I have bolted/riveted a 3/4" extension onto XR200s that reduce lever pull by 40%, and easy to convert back to stock.  

 

I have a modded engine in one XR and needed stiffer clutch springs to handle the extra torque which increased lever pull so I used both of the above.

 

My mod: http://www.thumpertalk.com/topic/953284-clutch-is-too-hard-for-my-8yr-old/#entry9967426

 

Towlieee's mod with pictures: http://www.thumpertalk.com/topic/690722-150f-easy-pull-clutch-mod-works-on-most-bikes/

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Thanks Chuck!  I think I will do as you did, extend the clutch arm.


An engine mount bolt (the nut) is in the way of extending it much.  I will switch it around to put the nut on the other side, then grind down the bolt head for more space.

 

The CRF 100 Clutch arm is 2.2".  I can extend it to about 2.7", that's a 22% reduction in pull.  And then can try a new cable if it needs more.

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OK thx for the replies.  I decided to extend the clutch arm 1/2 inch similar to Chuck's mod.

Then it touched the engine bolt.  So I ground off the offending part of the engine bolt.

Then the clutch cable angle was wrong, so I cut the strengthening ribs on the clutch cable bracket (to make it easier to bend).  Then bent it so the cable aligns with the new clutch arm.  It was so hard to bend the cable bracket, that I didn't bother to re-weld it.

CRF100clutch.jpg

Edited by WA_trail_rider

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The stock 100 perch/lever is horrible.  No matter what you do, you need to replace that.  I use a CR85 perch/lever. It's a must for kids and people with smaller hands.  Most people use the MSR setup.  It probably works just as good if not better. 

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I wonder if anyone makes a hydraulic clutch conversion for it? I did a little searching, but didn't find anything. They would probably be expensive if you did find one, but smooth and easy to pull.

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I remember back in the day, I re-drilled the pivot point on the perch (drilled it in front of original hole) and it made the pull easier. This was on an rm125 and was a "tech tip" in Dirt Bike magazine. I dont remember if i had to reshape the perch end of the lever though.

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my sons xr100 stock clutch perch was horribly stiff , bought a cr85 clutch perch with cable for $15.00 on fleabay and it is light night and day for him.

thought it was the cable but trust me it is the perch.

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Thats interesting, thought about ordering a CR85 perch but decided to go DIY to get'er done today.

 

I re-drilled the hole for the cable for more leverage.

IMG_0996.jpg

 

I removed the (OEM) plastic bushing and used a 1/4" drill.  The cable is at 21mm from the pivot instead of orig 28mm so this mod added another 25% reduction in pull.  Added to the 22% reduction (from extending the clutch arm see post#5 above) results in 42% less pull.  Note that cable angles are no longer optimal, might wear cable sooner, but by then I'll be buying a bigger bike (or replace the cable).

 

Note that for this to work the cable end has to be the small type with the (removed) plastic bushing.  This cable is HONDA original.

IMG_0980.jpg

 

I used an angle grinder with .060 cutoff wheel to cut the cable slots.
IMG_0987.jpg
 
It would be ideal to use a worn-out wheel (for a smaller radius). You have to set the cable adjuster so the cable slot (in the adjuster) allows more angle to let the cable aim at the new hole.  

 

The result is FINALLY the pull seems appropriate for a beginner - and a motorcycle that has a whopping 8 horsepower.

 

Seems like an aftermarket company focusing on XR100/CRF100 could locate a set of 4 lighter springs that could handle this whopping 8 horsepower. The kit would fit a 20 years span of Hondas, there's got to be a few out there in need of this.  If the CR85 perch works, a kit of china CR85 perch and lighter springs set could do it nicely.  I don't like that EZ-pull cable unit because it would extend the cable on this little bike, and it also adds friction.  Plus I'm DIY…..; :ride:

IMG_0988.jpg

IMG_0989.jpg

Edited by WA_trail_rider

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