Lightswitch Clutch?

[bikedude987]

I trail rode my new to me '06 yz450f last weekend.  The motor was a hoot, and the suspension was great for mx valving...but the clutch was either on, or off...  NO modulation, and a rather hard pull.

The bike is set up with a full Hinson clutch (basket, hub, pressure plate, plates) in excellent shape.  The pushrod is not mushroomed, the cable slides freely, and the lever is ok (not great, an fairly worn but working MSR, iirc) and the oil is new. 

It seems as if the leverage ratio is wrong in that I have to pull very hard but for almost no distance to engage/disengage the clutch. 

I'm going to see if new oem style plates will fix it, but barring that, where should I start looking?  Will a Magura HYMEC change the leverage ratio?  should I go back to an OEM lever/perch?

[turbo dan]

If the bike had been sitting for a long time the plates will only soak on the bottom.  You could replace them but with some regular use the clutch should work itself out.

It took a few hours on my 03 125 to get the clutch to smooth out.  I figured the basket had to be shot but it looked great.  After a few rides it began working properly, no more grabbing or chattering.

[ScwhettyNuttz]

Sounds like it has very stiff pressure plate springs.  May want to try the OEM springs if they will work with the hinson setup. 

[bikedude987]

Cool, only reason I didn't replace the springs is because Hinson says their springs are "to oem specs".  But there are a bunch of assumptions going on there as well...

Any feedback on the HYMEC?

[SteveThe Snakes]

Yz springs are very stiff I believe the Hinson are stiffer. WR450 springs are softer. I used stock springs in my built WR’s that put out way more hp than a stock yz. Never had a clutch slip. 

[ScwhettyNuttz]

My buds yz250f smoked his clutch plates.  He ordered tusk brand kit that included springs.  They seemed much softer by just compressing them by hand.  We used them anyways, and clutch pull was way better, and they dont slip at all so far. 

[toten]

if the pull is stiff, springs and perch assembly are the only real way to fix it (I'm assuming your cable is in good shape, lubed, etc)

[shredmasterz]

My 2007 yx450f  clutch is all stock.  The clutch pull is not heavy and I can modulate the clutch with ease.  For comparison my other bikes are GasGas with hydraulic clutches and they have a light clutch lever pull.

[bikedude987]

UPDATE:  I put the OEM clutch perch from my yz250 (same part numbers as the 450) on the 450 and it made all the issues disappear!  the clutch is butter now with a wide friction zone and a relatively easy pull.

PO must have bought the wrong Works Connection perch/lever because the leverage ratio was all wrong.  

Ordered a used OEM yz450 perch and hot start and can ditch the 'chitty but pretty WC clutch.

Might still go for wr450 springs if I decide I want to reduce clutch pull further.