Clutch slipping

[Redlined50]

Ok when my bike gets really warmed up like a ride over 20 miles my clutch will start to slip if i give it too much gas in the upper gears and i can feel it slipping when i shift.

I have bled it lots of times, I have used a whole bottle of DOT 4 brake fluid and it still does it but only when its really warmed up, i have zero problems driving to and from work everyday 10 miles each way.

Any ideas?  Its a 2001 monster 600 (wet clutch) with about 11k miles 

[ScottRNelson]

If the clutch is slipping, it either means the clutch plates are worn out or your springs are weak.

Bleeding the clutch and changing clutch fluid will do nothing whatsoever to improve a slipping clutch.

Whether it's the clutch plates or springs, you'll need to open it up.

One other possible cause would be the wrong type of oil.  If you used oil not designed for motorcycles, it could make the clutch slip.

[Redlined50]

i use mobil 1 v-twin 20-50

[ScottRNelson]

i use mobil 1 v-twin 20-50

Looks like you'll need to open it up, then.

[Howie]

Check the free play in your clutch lever too.  You need 1 - 1.5 mm play.

[Redlined50]

if the clutch is actually shot why does it not slip when its cool 

[ScottRNelson]

if the clutch is actually shot why does it not slip when its cool 

I don't know why, but the only bike I ever had where the clutch slipped was a DR-350S and it only slipped when hot.  It might have something to do with how oil works when hot compared with cold.

[He Man]

There could be two different metals in contact with each other, and one may expand more than the other which causes it to slip more noticeably. However, may I ask, do you ride your clutch alot? or use it in traffic often? Wet clutches usually last a really long time.

[Hedgehog]

Check the free play in your clutch lever too.  You need 1 - 1.5 mm play.

Just to reinforce this a bit; people used to think that the araldited screw in the handle was to adjust lever height.  It's not, and if you chip the araldite off and adjust it, you may cover the vent port in the cylinder.  When that's covered, the hot expanding fluid can't make it back up to the reservoir, and it's like riding with the clutch (or brake) lever partially squeezed.  Even when it's hot you should have enough free play in the lever that you can tell when the pin makes contact with the piston in the master cylinder.

[Redlined50]

Just to reinforce this a bit; people used to think that the araldited screw in the handle was to adjust lever height.  It's not, and if you chip the araldite off and adjust it, you may cover the vent port in the cylinder.  When that's covered, the hot expanding fluid can't make it back up to the reservoir, and it's like riding with the clutch (or brake) lever partially squeezed.  Even when it's hot you should have enough free play in the lever that you can tell when the pin makes contact with the piston in the master cylinder.

when i bleed and pull the lever too quickly i get a spray of fluid out of the reservoir, doesn't that show that the screw is not in too far? or is that something totally different?

[ScottRNelson]

when i bleed and pull the lever too quickly i get a spray of fluid out of the reservoir, doesn't that show that the screw is not in too far? or is that something totally different?

That means that you forgot to put the cover on before bleeding it.  The spray is normal.  I did the same thing on my ST2 and sprayed a small amount of brake fluid on the speedometer face without realizing it (everything else was covered with rags).  The plastic cracked in multiple places because of that.  I'll be more careful in the future and keep the reservoir covered when bleeding the clutch or brakes.

[Redlined50]

i always leave the cover off to easily watch the fluid level and add fluid when needed, if you pull the lever slowly the first couple inches its fine

[Redlined50]

im also noticing a little sticking of the lever right at the friction point