Quick turn throttle cable / shorter clutch pull

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#1
How's that for a convoluted title? Sheesh!

Anywho, a LONG time ago (I'm guessing 2000-ish) I was able to locate a product through a member on this website that was a throttle cable with a little box in the middle of it. Inside the box was a pulley system (I think...it was sealed) that produced a one to two effect - pulling the cable 1/2 inch on the throttle tube side produced a one inch movement on the carb side. I never used the cable and ended up giving it to a friend of mine.

My wife currently races a 2003 YZ125 and since we bought the bike last year we have been fighting with the clutch set up. I run an Applied perch and lever that allows adjustable end point, and with my wife having small hands and short fingers she has to run the lever in pretty close. This of course makes the window of acceptable clutch free play VERY limited. This wasn't an issue on her '00 KX125 or '01 YZ125, but for some reason on this bike when the clutch heats up the free play changes and she has an issue with stalling.

So, how are these two items connected? I would like to find the manufacturer of the 1:2 throttle cable and see if it can be customized to a clutch application. That way she can run the lever further in where she is really comfortable with it and still allow proper engagement and disengagement. The issue is I have no clue who made the cable originally, nor can my friend remember that I gave it to (he eventually pitched it). If anyone has a lead I would GREATLY appreciate it.

Other than that if anyone has any ideas on how to deal with this issue or another product that would help that would be appreciated as well. About the only other idea I had was to take off the clutch actuator arm (down on the case) and take off about 1/4" (cut and re-weld) to decrease the radius is must travel and allow more actuation with less lever movement. My only concern there is increasing the effort required to pull the clutch.
 

truespode

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#2
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#3
sounds like a cool device but if you're worried about increasing the effort needed to pull in the clutch, that 2 to 1 thing you're talking about will make it twice as hard to pull in the clutch, and maybe even make it harder to keep the bike from stalling since you will have half as much travel between engaged and disengaged. but if you still want to try it you could always look on e bay. I swear you can find anything on that site.
 
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#5
Truespode! I'm down with some OBC...I'll even kick your butt at go-karts again, my treat. Just let me know if/when you're coming up.

dpaxson - thanks for the tips, something to consider for sure. I don't know if it would increase pull that much or not since there was kind of a mechanical advantage with the pulleys. I'll definitely scan **** though, thanks!
 
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#6
Patman - that Moose set up is interesting, but does it actually change the amount of travel or just the leverage? Leverage wise she's good - unless the shortened actuator arm changes that. If it changes travel that would be perfect for this application. I'll have to shoot Moose an email and see.

Thanks for the lead.
 
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#7
Well, the leverage and the travel are directly related. the more leverage you have on the clutch, the more pull it will take to disengage it. this is the opposite of what you want.
I think the moose device simply gives you more leverage, making for easier clutch pull, but also longer clutch pull.

no matter which method you choose, if you make the clutch pull to be shorter, its going to be more difficult.
 

truespode

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#8
Tiddlerracer said:
Truespode! I'm down with some OBC...I'll even kick your butt at go-karts again, my treat. Just let me know if/when you're coming up.
I wanted to come up this year but wasted a week of vacation and am using 2 more days for the 10 hour Harescramble.

I *might* be up around turkey day but that is doubtful. I am going to try and be up there next summer (I know, I say that every year).

And this time you play terminator with the out of control kids on the go-carts :)

Ivan
 
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#9
CHR!S said:
no matter which method you choose, if you make the clutch pull to be shorter, its going to be more difficult.
That is fine though. Again, it's not a matter of strength, it's a matter of little hands and short fingers. She can deal with a stiffer clutch if it means easier to grab (lever distance from the bar) and will full engage and disengage with the shorter travel.
 

Patman

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#10
I'm suprised the lever really needs that much travel to do it's thing. Most bikes I've been on don't require much distance to evgage/disengage. My son had the small hands problem when we got him on his CR85 and I put a set of ASV F3 levers on it and brought them in a bit. He had plenty of throw as well as having the levers closre to the grips. Maybe just a simple change of levers? (even though it sounds like you have sort of gone that route).
 
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#11
You're asking a lot of your 2-stroke if you expect it to idle in gear. Just teach your wife to keep the bike revved up when she comes to a stop. After an extended stop, she'll just have to let it stall out. She can start the bike in gear, right? If you can't start it in gear, then you have a clutch drag issue or a worn out top end.
 

High Lord Gomer

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#12
76GMC1500 said:
You're asking a lot of your 2-stroke if you expect it to idle in gear. Just teach your wife to keep the bike revved up when she comes to a stop. After an extended stop, she'll just have to let it stall out. She can start the bike in gear, right? If you can't start it in gear, then you have a clutch drag issue or a worn out top end.
Where did he say anyhting about having it idle in gear? She does hare scramble type races and the clutch does heat up and change in tight sections. Believe me, she doesn't need any help in the "how to ride" department!

I think the hydraulic unit (shuddup, Ivan) is the way to go. You can adjust how far the lever rests from the bar and have a consistent engagement point even as the clutch heats up (though it does pain me to agree with the guy without pants).
 

truespode

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#13
High Lord Gomer said:
You can adjust how far the lever rests from the bar and have a consistent engagement point even as the clutch heats up (though it does pain me to agree with the guy without pants).
Only problem there is the lever still will rest outside her reach.

I think an adjustable unit that brings the reach in is more important than the engagement point.

And I agree... she does not need any help in the "how to ride" department. She can roost most guys on here.

Ivan
 

jeffd

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#14
The hydraulic set up will allow for adjustment of the lever position much like you can adjust your front bake lever's relative position to the grip/bars.

The cool thing about the hydraulic set up is that it is easy to pull, smooth, and consistent.
 
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#15
Thanks for the input guys, I appreciate all the suggestions. If I can't get it sorted out this season maybe Santa will bring her a juice clutch for Christmas.