There is a ball bearing that is held captive in the actuator plus the ball bearing inside the engine.

A new actuator will have a new ball bearing inside but not the screw and nut.

AHAH!!! That explains it. Also shoots holes in my theory. (At least I have a good imagination.) 1971DT250 - You're my hero! Thanks! ..... By the way, yesterday you asked how my shift lever and splines were. Finally I have something to be proud of. My spline looks great and here's my shift lever:


If my shift lever looked any better it would be illegal to own it.

My order for a new one has been placed and confirmed. Just to think - yesterday morning I knew nothing about these actuators. Thanks everyone.

Guess what came in the mail today? Take a look.


It looks fantastic. Although these things are a little pricey, I've tried to make everything on this bike as good as I reasonably can and I just couldn't bear the thought of riding around with a broken one hoping it would hold up. So.... I spent the money....and as they say: It's MY money. I'm a happy guy. Thanks everyone for your help. (again)

Hello - Can you advise where did you get the new DT1 actuator arm from as shown in the photo - looks really nice. Do you have a link with the contact details so that I can get one, thanks Syd

Hello Syd. These were made a few years ago by 2 different vendors. They are not available anymore. If you have an actuator that has a cracked nylon spiral worm gear but is otherwise in good shape then I suggest this brass replacement from kdirepros.com.

www.kdirepros.com/Clutch-Actuator-Worm-Gear-p/214-16340-00.htm

 

Thanks for the info which is much appreciated. Any idea of where the other type of actuator with the nylon spiral as shown in the photo comes from?

These were made by 2 different vendors about 5 years ago. Both stopped production shortly after they made a few dozen. They said that the production costs were too high and that they were difficult to make.

I stocked up when I had the chance.

 

 

Thanks again for the info. Not sure what to do as things are not helped at present with USPS temporally suspending all mail deliveries to New Zealand and Australia due to transport problems due to Covid. May have to look at trying to fix the existing split nylon spiral