clutch actuator help for 400

[dirtymartini]

I'm just getting my 400 engine back together and can't get the clutch to disengage...the springs seem close to spec, but there is a lot of play in the actuator arm and the distance of the arm at zero is about 35mm when it should be 42.5 to 43.5 mm.
Any suggestions?

[rob w]

If you are using the older of the two style "Bearing Cover/Clutch Actuators", you may have badly worn clutch "Push Rods". The rounded ends don't have alot of contact area, and commonly wear to a point where you've lost some of the throw travel.

New the (2) push rods (Pt. # 51.32.017.100) are a length of 4.260" or 108.20 mm each. There's also a 6mm ball bearing between the rods.

 I have remanufacturered those parts, they are available through Buehner's Supply and the cost for them is inexpensive.

If you have the newer style Actuator that uses the single long rod, w/cup and small bearing. I have one around here somewhere to measure it's stock length, but it'll take me some time to find it. I have not made any of those yet.

Good luck
Bob

[dirtymartini]

Thanks Bob! I know the end of the one rod is worn, I thought about giving Al a call...I'll defintely call him tomorrow. It's the old style with the two rods and ball bearing in the middle. There is a lot of slop in the actuator but maybe the rods are worn out. I'll measure them tonight. I never ceased to be amazed at the help and knowledge sharing on this forum...thanks again!

Paul

[dirtymartini]

I measured the clutch rods, and the rounded part is worn right down on one of them. Looks to be about 1.5mm shorter than spec and both rods have wear in the flat ends where the ball bearing rides. I'm going to order some new rods today and see if that works.

PC

[Kip Kern]

Once you have the correct 108mm rods (2), and a 6mm ball between them, you can adjust the actuator arm distance by pressure plate thickness on the outer clutch, there are three or four thicknesses to choose from.  This is assuming you have the proper thickness steel and brass clutch plates.  Another item you may wish to check is the hardened bolt that the rod pushes on, it gets worn too. CIAO

[dirtymartini]

Thanks Kip, I'll check that out. Now that I think about it, I remember my other brother trying to get this running about 12 years ago and having some clutch issues. I thought he had taken it to a KTM dealer in Texas where he was living at the time. It does look like the hardened bolt had been adjusted inward to try and take up some of the slack. I have new rods and a pin for the acuator arm on the way. Are those diferent thickness plates available anywhere?

Thanks,
PC

[Kip Kern]

The hardened bolt only serves as a stopping point for the tip of the outer rod.  It can't be adjusted as it seats in the pressure plate and will strip under pressure.  The bolt will sometimes wear in the center from rod spin.  I've seen a hole as deep as 1mm!  A little distance on the clutch side can mean a lot on the actuator arm.  Another place to look is the actuator drum in the casing, it will wear a groove in it and allow rod play at the right side of the engine.  You just have to play with it but it is easy to do especially if you want to get the proper clutch action.  The thinner the pressure plate = greater distance of the actuator arm.  The thicker the pressure plate = less distance of the actuator arm.  Ciao!

[Auto5guy]

I think Kip is talking about hardened pin in the actuator drum that the push rod sets against on the right side of the engine.  On every clutch actuator I've had apart the rod has cut through the chrome and burned a divot into the hardened pins.

To fix it you push out the pin that holds the drum in its housing.  When you pull the drum out you will see the hardened pin with the groove burned into it.  Pull the O-ring off of the drum.  Using a 1/16th drill bit drill from the groove the O-ring sits in to the hidden end of the hardened pin.  Use a 1/16th punch to push the pin out far enough to grab it with pliers.  Once its out just rotate it so a good surface of the pin will contact the push rod and push the pin back in.


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