350 pushrod seal replacement

[ty_tk421]

I'm new to the forum & new to the Ducati single engines. I'm needing some guidance on removing the pushrod seal on a 350 case. To give a little background- my grandfather recently passed away and he left me his two Ducati race bikes, a 350 & 250. The 350 engine had a blown piston so I'm in the process of an engine teardown/rebuild. My engine familiarity is with 70s Honda twins so this is new territory for me. I need a little advice from seasoned Ducati owners to compensate for my lack of knowledge & the lack of info in the manuals. Any help is much appreciated.

I'm wondering which direction I access the seal from- do I remove the staking and access the seal from the outside? Or do I remove the bearing & go from the inside? I want to know what I'm doing before I start prying so as not to damage the castings on the case. Again, any tips are greatly appreciated

[Duccout]

Hi and welcome.

You have to remove the staking and then you can hook out the washer and rubber seal. The new seals are proper lipped oil seals that tap into the housing, but require that the housing is perfectly round, which means removing all of the staking, so you need good eyesight! I use a small tool on a Dremel to gently ease away the staking and a smear of silicone around the housing to make sure it is sealed.

Good luck,

Colin

[Wolf]

Hi Tyler

I assume you have a narrow case motor, am I right? I think I'm in a similar place. I've bought a new seal for my 450 and it came with an instruction to install it to the motor casing. deepl.com translates it to:

Remove the washer and the old rubber grommet without removing the knurling (riveting) Insert the metal disc with the visible part of the oil seal facing inwards into the housing, applying pressure.

If the retention of the old bead is too weak, replace it with a new one. The application can be made easier by using Loctite

Kind regards

Wolf

[Hiya9612]

Hi and welcome!! I bought my first Ducati back in the summer (a late 350). After a couple of hundred miles I decided to do an oil change and take that opportunity to look inside the engine. To my horror I found a bevel drive gear with a tooth missing and subsequent inspection found a multitude of additional bodges perpetrated by the butcher who last worked on the engine. What this is leading up to is; that these engines need to be built with a high level of precision, there are shims everywhere, DON'T MIX 'EM UP, DON'T LOOSE THEM, they need to go back where they came from unless you fit a new component which needs a different shim thickness.
I found this blog which gives step by step photos of a Ducati single renovation: https://moticosroyo.com/ducati-road-desmontar
It's a Spanish blog, so set your browser to translate into English and the builder isn't a Ducati expert, so anything mission critical, check with the guys on here.

[Eldert]

Hi Tyler

narrowcase pushrod seal is not the same as a widecase . a widecase has a seal with a 14 mm o.d . as in the picture
that Wolf posted . a narrowcase seal has a outside diameter of 22 mm . Nigel ( Lacey Ducati ) sells a housing with a seal that fit the narrowcase . or you could find a seal and make a small housing for it on the lathe

Eldert

[ty_tk421]

I was able to get the old seal and washer removed without issue. A few minutes with the Dremel made quick work of the staking (thanks for that suggestion, Duccout). I've got the housing with seal from Lacey Ducati on order along with some other bits and pieces. I should soon be ready to begin reassembly of the bottom end.

Thanks again for all the feedback & guidance.

[Wolf]

I'm fiddling around with the pushrod seal. The boring is something larger than 14 mm, hard to measure. The Vintage Ducati part seal has a diameter of 13.6 mm. Do you think it is a good idea to glue it in with loctite 638 and to bridge the gap with stripes of spring steel?
Thanks and regards
Wolf

[Duccout]

Hi Wolf,

Did you get the Lacey seal? They are the correct size for the housing. You may be OK using silicone to stick the seal in with, it is very tough once it has set. What do others think?

Cheers,

Colin

[Wolf]

Hi Colin,
it is the part from Ducati Vintage, maybe not the best choice in this case....
Wolf

[Jordan]

Do you think it is a good idea to glue it in with loctite 638 and to bridge the gap with stripes of spring steel?

That should work, but it would be nicer to make a new part so no shim strip is needed.
There might be a tame machinist in your area?

Loctite is brilliant stuff as a last resort.
I don't like that it isn't easy to know if it has been used, and there is a different removal process if a part has been installed with it.