Lubricate Focomat V35 helicoid

Hi all. I'm wondering if it's possible to access the helicoid on this enlarger without breaking it. The V35 I have doesn't have the original lens, so I've put an El-Nikkor 50mm on but the focus ring, though it turns, is very stiff and I can also feel that there is some dirt in the mechanism. Has anyone tried this? Thanks.