Specs for replacing clutch plates and springs?

[wirehairs]

I haven't found the minimum specs for the clutch spring length or clutch plate thickness for my 82 Maxim (XS400J). Could someone share that with me?

This is my first time changing a clutch. The clutch was slipping; I could be in 1st gear with the clutch handle out, and the bike wasn't moving. I need to look at the plates closer, but I didn't see any obvious warping of the disks or burn marks. I understand to place the metal plates on a flat surface to look for warping. I admit to being unsure when a clutch cable adjust will fix a particular issue over replacing the plates.

The bike has 15K miles on it, and I assume the clutch has never been replaced.

Thanks for the input!

 

[buschkj24]

First adjust the clutch properly to see if that fixes your problem. To do this, look at the left side of the bike and you'll see a black plug that will pop out on the cover that says yamaha yikes. Pop that black cover off and loosen the nut, then go to your clutch lever and screw in the adjustment knob (this will put slack into the cable) then go back to the side of the motor and screw the adjuster in until you feel resistance. When you feel it, back the screw off about 1/4 to 1/2 turn. After that screw that lock nut back down and replace the black cap then adjust your clutch lever to allow 2-3mm of slack. Then fire her up and see if that fixed the problem, if not then refer to the owners manual on how to replace the clutch. It's a fairly easy component to repair or replace but take your time and make sure it's done right the foray time otherwise you'll be taking it apart again soon. The manuals are found on the sticky and you can use the ones on thread #3 for the DOHC.

 

[wirehairs]

The oils is already drained out, so at this point, I'd like to measure my plates and spring. So, I still need those specifications, and I don't see them in the manuals I've downloaded online.

 

[xschris]

here is what it is for the sohc model. I know yours is a dohc bike but it may give you an idea what to look for.

 

[wirehairs]

Thanks Chris. Wow, so only 0.3mm leeway on those friction plates. I'm guessing those specs are probably the same from the DOHC, but it would be nice if someone can confirm that.

 

[xschris]

Remember these pads are soaked in oil all the time so wear is very minimal. I have pulled plates out with 20k miles on them and they where still in the limits of use.

 

[wirehairs]

Yeah, I get that. But the plates were slipping - I was able to be in 1st gear, with the clutch handle completely out, and not be moving. The oil I drained out looked awful, but still figured I need to check the plates.

 

[xschris]

If it's doing that with a properly adjusted clutch then there may be issues.

 

[buschkj24]

Best bet to replace fiber and steel, dump some quality oil made for wet clutches, then adjust the clutch to proper operation.

 

[xschris]

New springs also

 

[wirehairs]

So I finally took a close look at the steel and friction plates, and they really do look good to me. I don't see any wear, discoloring, etc. In measuring them, the metal ones are all at 2.00mm, and the friction ones at 3.00mm. The variance is tiny. The springs seem to vary more: 34.74, 34.74, 34.87, 34.85, 34.88, so still within 0.14 of each other.

My metal plates are 1.6mm, so I'm guessing the Maxim's are beefier, unless someone installed the wrong plates in here??

 

[buschkj24]

Yes the maxim should be a little more "beefier" since the DOHC make more power than the SOHC 400's. Even if the fiber is within spec they still may be shot... The fiber would have been oil soaked for sometime when the bike was new then it sat for a period of time and dried out. The fiber then becomes like linoleum and will slip like it's trying to grab a wet ice cube. Still replace the fiber, it's not too expensive and your bike will run/shift much better.

 

[XSLeo]

There are a few other things you can do to improve your clutch.
On the steel plates, they are stamped out. Look close and you will see that one edge is slightly rounded, the other slightly sharp.
Use 150 grit sand paper to just break this sharp edge. Make it match the rounded edge. This lets the plates slide in the basket and on the hub easier. Also sand the entire surface, this will rough it up and increase the grip.
On the fiber plates they have the same sharp edge.
Replace the springs. I think they are the same size as most clutch springs. Stock were around 45-50 lb. springs when new. After 30+ years they might be more like 35-40.
I would find some in the 60-70 lb. range.
I think Yamaha still sells new fiber plates.
Your fiber plates are #4H7-16321-01-00, springs, #90501-26148-00
Searching these numbers and you should find something.
Boats.net says the fibers are not available, spring are.
Other parts places may have them.
Leo

 

[XSLeo]

Oh yea, a well lubed cable and actuator improve the clutch too. Lube the actuator with general purpose grease, the cable use the funnel and oil method. Not the cable clamp on thing that uses spray lube, won't last long or work well.
Leo