1973 Penton Hare Scrambler clutch

[brian kirby]

The 400 friction plates were bronze, the bronze plates are better IMO, they basically never wear out.

Did you try to pry that side of the clutch up while the lever was pulled in to see if it was stuck?

Brian

[Andreas Piepke]

That's a good idea. No unfortunately I didn't do that and now the clutch is apart. I'll try smoothen all surfaces over which the plates move and if that doesn't work I'll try your suggestion.

Cheers

Andreas

[JP Morgen]

In my experience, the clutch springs need to be individually adjusted to get the pressure plate to move straight and equally outward. If you pull in the clutch lever and then operate the kick starter you can see the wobble, tighten the springs near the high spots and loosen the ones near the low spots. Good luck.

[Andreas Piepke]

Hi All,

Today I put the clutch back together and did a number of things. I found that the bolts holding the clutch springs had slightly different lengths, see:



I replaced 3 of them with correct length bolts I took from a 1976 scrap engine I have. I filed the outer cage again to smoothen the marks in it. I lubricated the clutch cable and used a pressure plate recovered from the 1976 scrap engine (part number #51 32 006 599 instead of #51 32 006 099 I found installed in the clutch). The clearance of the lever is OK. I tightened all springs uniformly so 1. 7 mm thread shows on all of them. This is the minimum needed to get the safety pins in. I re-tightened to achieve uniform lift-off. I hope the clutch won't slip. Now the clutch lifts off uniformly and operates with much lower hand force than before. I can't pinpoint the issue as I changed several things at once.

Thanks for you input

Andreas

[Daniel P. McEntee]

I haven't worked on a KTM clutch yet, but have been following this thread just for the information presented in case it's needed in the future. I think the lesson to be learned here is pay attention to details, all the details. It's easy to get in a hurry,or caught up in the excitement of finishing up a project and get a case of tunnel and miss a detail that we sometimes take for granted. Judging from what I have read here and the description of the problem, the bolt length differences may have been at the heart of the problem. Great thread, though and I really liked the detailed photos. Glad you got it squared away.
  Type at you later,
   Dan McEntee

[Andreas Piepke]

I observed another issue, not mentioned in my previous post. One of the holes in the original pressure plate was deeper than the others. The corresponding screw was probably not tight, allowing it to rotate and work its way into the metal of the pressure plate. This in turn allowed the screw to go in deeper and get in contact with the metal of the outer basket. This is the reason why for on one of the bolts the head seems ground short. This is actually the reason why I replaced the pressure plate.

Cheers

Andreas

P.S.: Here a picture describing this problem.