How do you check the clutch friction plates for wear?


17 replies to this topic
  • Family Man

Posted June 08, 2008 - 08:11 PM

#1

I've noticed my bikes, 07 450, power seem to slip occassionally in 4 and 5th gear. When I pin it on a strech on the paved road, around 2/3 of the way threw the power. Today, I went to give it gas to roost out of a mud pit section on a track and the bike didnt even spin the rear tire, I was a gear to high 3rd, clicked it down to 2 and it took off. Ussually it would just bog a little if that happend. Im not sure if my clutch plates are toast or not as it doesnt slip all the time. Should I just go buy new friction plates? What are some good ways to tell if your clutch needs new fibers?

  • Racer24

Posted June 08, 2008 - 09:23 PM

#2

its usually the steel plates that you check to see if it needs replacing. as you go deeper through the stack you might see some purple or brown tan colored steel plates. if u should consider getting new plates. But dnt rely on the first two steel plates you have to look at all of them

  • Family Man

Posted June 08, 2008 - 09:46 PM

#3

So, basically if the steel plates look burned it time for new fiber plates?

  • SXP

Posted June 08, 2008 - 09:52 PM

#4

So, basically if the steel plates look burned it time for new fiber plates?


Both the steel and friction plates have a thickness range they have to be within. This can easily be measured with a caliper and the specs are in your manual. If they are nearing the lower limit it's time for a change. Or, as stated above, if the steel plates have started blueing from excessive fanning, and the friction plates look and smell burnt, it's time to change them.

  • Racer24

Posted June 08, 2008 - 10:07 PM

#5

So, basically if the steel plates look burned it time for new fiber plates?


well usually i wouldnt just buy friction plates or steel plates alone, you buy them as a set

  • YZ125 DR650

Posted June 08, 2008 - 11:16 PM

#6

on the steels dont forget to check warpage.... lay them on a truely flat surface and check with a feeler gauge.
ALSO dont forget the basket... if you're wearing out plates that fast more then likely your basket has taken some abuse also

  • 642MX

Posted June 09, 2008 - 04:23 PM

#7

So, basically if the steel plates look burned it time for new fiber plates?


If they look burned they are also warped which means you need to replace them. Always replace the clutch as a set with new fibers, metals, and springs. Usually the springs give out first, causing a lack of clamping force and then your clutch will slip. When I ran a standard clutch, I would replace the springs every 6 months.

  • William1

Posted June 09, 2008 - 04:34 PM

#8

Two things you have to do. First, measure the thickness of the friction plates, confirm if there are within service limits. Secondly, measure the the clutch spring free length, confirm they are within limits. In some instances, the steel plates get warped (very rare) and they get checks on a machinist flat with a feeler gauge. The service manual has terrific write ups covering this.
If the basket gets notched, it may not cause slippage rather it tends to manifest as a grabby clutch, no engagement to a point then sudden full engagement.

  • Family Man

Posted June 10, 2008 - 01:43 AM

#9

Its not grabby, that I've noticed. It just seems to slip occasionally.I can notice it on the pavement in 4th and 5th gear, its slight at this point but enough to notice. I dont have a caliper yet so I wanted to see if there were other ways to tell if its worn. It still shifts great. I have noticed the bike is easier to kick through, still start first or second kick on top dead center. I havent been thinking to much about it untill the wheel didnt spin under power in the mud. Also, the manual say to torque the bolts to 7 and a half foot pounds, could I torque them to 10. My torque wrench starts at 10flbs and goes to 150flbs.

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  • kawamaha

Posted June 10, 2008 - 02:16 AM

#10

I don't want to return from a track with a worn clutch, otherwise I don't want to buy a spare clutch because I don't ride a bike for more than 2 years. what I do is buying one steel plate. if the clutch is slippery it is because the inner and outer clutch basket are laying against each other so the springs cannot put force on the plates. then I just add one plate to rebuild the gap between the 2 baskets. of course it's time to change your clutch plates soon.

this helps at least to know if your plates are worn or avoid to drive to a track and return frustrated due to a worn clutch :thumbsup:

  • grayracer513

Posted June 10, 2008 - 07:32 AM

#11

... the manual say to torque the bolts to 7 and a half foot pounds, could I torque them to 10. My torque wrench starts at 10flbs and goes to 150flbs.

Do you think that torquing your front axle nut to 100 lbs rather than 70 would work out? No, you can't torque them to 10 ft/lb.

The clutch spring bolts are not critical torque items. They just need to be properly tightened.

  • Family Man

Posted June 10, 2008 - 10:00 AM

#12

sounds like I should probley buy some tools then too.

  • Family Man

Posted June 10, 2008 - 04:26 PM

#13

I bought a new clutch set today,steels and frictions.OEM Yamaha. Im in the process of installing it. I removed the old plates and the steels. The steel plates do look "burned". The friction plates do have some tread left? I dont have a caliper so I dont know if there beyond the limit. There is some notching on the inner hub and basket. How much notching is ok, or is any bad?

  • 642MX

Posted June 10, 2008 - 04:38 PM

#14

I bought a new clutch set today,steels and frictions.OEM Yamaha. Im in the process of installing it. I removed the old plates and the steels. The steel plates do look "burned". The friction plates do have some tread left? I dont have a caliper so I dont know if there beyond the limit. There is some notching on the inner hub and basket. How much notching is ok, or is any bad?


I hope you got some springs too.

Any notching is not good. If the plates stick to the basket when they slide in, then I would replace the basket. Another good sign that they are shot is if the bike wants to creep forward idling in gear with the clutch pulled in.

  • William1

Posted June 11, 2008 - 02:54 AM

#15

You'll notice if the notching is a issue if the clutch seems grabby..... engaging....engaging then sudden grab.

New plates in, give the bike a hour of ride time before you look for this and begin analyzing. Some notch is common, deep notches are bad. LOL, I never measured to determine what was too much.

  • Family Man

Posted June 13, 2008 - 09:41 PM

#16

I replaced the clutch plates, frictions and steels. The old frictions still looked like they had tread on them. Im confused, does tread mean wear? After installing the plates I noticed my clutch lever was super loose. I adjusted it a went for a ride. Wow. I thought that I was just spining my tires on the loose ground alot before. Now I have way more traction, it feels like I do. The bike pulls much harder. I didnt realize the clutch was as beat as it was.

  • William1

Posted June 14, 2008 - 03:23 AM

#17

Yhe pfriction plates can be well past thier useful life and still 'aooear' to be usable. You have to measuer and compare to the service limits. By the book!

  • Family Man

Posted June 14, 2008 - 08:31 PM

#18

Yeah, the manual states that 5 thousandths of an inch is the differance between useable and shot. I dont think I could see a differance, but man can I notice one hell of a differance on the bike.:thumbsup:





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