Yz450 for a woods bike

Not to change the subject, but I have a different question on the clutch on this bike.  Bike is a 2011, 90% woods bike with all stock components, "Woods Map", running Rotella T 15W-40, non-rekluse clutch.   The problem that I'm having is that in extremely tight stuff, or if I get stuck on a hill and have to slip the clutch to get going the clutch/bike tends to heat up and start engaging different.  It will dis-engage fine, and will not drag, but when I go to release the clutch to take off I have little to no, what I'm going to call "slip zone".  Basically when I let the clutch out it just wants to lurch and take off which makes it really hard to really control the bike in the super tight stuff.  If I get out of the tight stuff and get on some open to get the bike cooled off some, the clutch will go back to working better, until I get into the tight stuff again.

 

My question is, could there be something wrong with my plates that when they heat up they are causing this?  It does gain some freeplay in the lever, but I can adjust this out when I stop and it will still do the lurching thing until it cools off.  I've pulled the clutch out and the friction plates are all still right in the middle of the spec range, but I did notice that the steels do have some slight bluing on them but appear to be flat when placed on a flat surface.  I'm wondering if these steels heat up and start warping causing the clutch to act up.  

Plates that warp out of flat would cause the exact opposite of an abrupt, grabby clutch; the clutch would drag at idle and the engagement would be long and mushy rather than sudden. 

 

It's probably your plates or your oil, or something with both that affects how they work together hot.  Just for fun, you might try Mobil1 Racing 4T on your next oil change and see if anything changes.  If not, figure a new set of OEM or better clutch plates. 

I was thinking of going the oil route first, being since I'm due for one, and its cheapest.  I've always ran Rotella in all my bikes and never have had an issue, but they are both 250's and this is the first 450.  

Greyracer, can u pls look at my prev post and give opinion.

Weighted flywheels do make a considerable improvement in the whole way that the engine operates at low speeds.  It's not going to "solve" your problems, but it will help.  Easy mod to do or to undo. 

Thanks grayracer, if all I feel I need is lower speed at idle and less wheel spin down low what weight you suggest ?

Or do I change rear sprocket too, if so to what tooth, I'm currently 13/49

Or do I change rear sprocket too, if so to what tooth, I'm currently 13/49

12/49 or 13/52 etc. Some say 12t sprocket prematurely wears chains and sprockets but I haven't noticed. Obviously your top speed will decline and you'll shift more too.

Thanks grayracer, if all I feel I need is lower speed at idle and less wheel spin down low what weight you suggest ?

 

What year is your bike?

2006 and I Don't really want to change front sprocket as it makes engine work harder and yes more shifts, I feel as if flywheel is my answer just want to hear what the expert says before changing anything. And I do run Mobil 1 4t and have no clutch issues ever.

For an '06-'09, get the GYT-R 8 or 9 ounce "off-road" flywheel, or another with a welded-on weight ring in the 8-12 ounce range.  It's not a cure-all, but it does help. 

Will it help slow my rear spin issue and slow me down at idle , they're my only concerns

2006 and I Don't really want to change front sprocket as it makes engine work harder.

Who told you that rubbish?

Put 13-51/52 gearing on it, run quality terrain correct tires at the correct pressures, learn how to ride the clutch and ride a gear higher, make sure the suspension oil and linkage bearings are fresh, flywheel weight to slow the engine response down and help stop flame outs.

The flywheel will hep with wheel spin, but you shouldn't run the idle much under 2000.

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