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1970s 250cc street scrambler valve stem oil seals ?

Posted: Wed Aug 14, 2024 11:05 am
by insanity
Hi All,

Just a poll of sorts, how many different types of valve stem oil seal are there for NON desmo singles ?
I ordered what i thought were the type in the image, but received seals that don't snap into the groove on the valve guide,
but rather just sit on the shaft free to ride up and down with the shaft, thought I would ask before bleating to the vendor.

Thanks
Lozza

Re: 1970s 250cc street scrambler valve stem oil seals ?

Posted: Wed Aug 14, 2024 12:16 pm
by Duccout
Hi,

There are different materials that the seals are made out of, but they should all fit over the lip at the top of the guide. Are yours too big to locate on the guide? The ones in your picture are correct.



Colin

Re: 1970s 250cc street scrambler valve stem oil seals ?

Posted: Wed Aug 14, 2024 1:08 pm
by Jordan
It sounds like the supplied seals are not standard, but of a type once commonly sold at car spares shops.
As said, they grip the stem and move with it, and the large "umbrella" shape tended to keep some oil out of the guide.
Maybe they're not as effective as the standard seal, but a little oil down a bronze guide isn't such a bad thing.
They should last indefinitely as they don't rub on the stems.
They do need space, which I guess is sufficient with hairpin springs.

Re: 1970s 250cc street scrambler valve stem oil seals ?

Posted: Wed Aug 14, 2024 2:25 pm
by Jon Pegler
Some of the Spanish singles do not have a groove on the top of the valve guide for the standard seal to fit into.
They use a car type seal that presses onto the top of a plain shank, ungrooved guide.
This does not move with the valve stem, but fits snugly onto the top of the guide.
As used in Stradas, Forzas, Ventos and some late Scramblers.

Re: 1970s 250cc street scrambler valve stem oil seals ?

Posted: Thu Aug 15, 2024 4:41 am
by insanity
Hi,
Thankyou.
I received the black one in lieu of the white (correct) ones.

Re: 1970s 250cc street scrambler valve stem oil seals ?

Posted: Thu Aug 15, 2024 9:24 am
by themoudie
G'day insanity,

May I suggest that you have a look at the two types of seal offered on this website and note the information given. Personally, I prefer the Viton type for their robustness.

Lacey_valve_stem seals_page1

Good health, Bill

Re: 1970s 250cc street scrambler valve stem oil seals ?

Posted: Fri Aug 16, 2024 3:33 am
by insanity
Hi Fellows,
I Thankyou Gentlmen, They do fit with a little persuasion !
I was being a little cautious in case i had to return them, I bought locally (Australia) because a 10 cent part from overseas usually incurs a $50.00 shipping charge, though I hold Mr Lacey and others in high regard, postage is generally outrageous and the Oz Dollar is frightful at times.

I appreciate your knowledge sharing as I belatedly learn things Ducati Singles.

Cheers Blokes.