valve collet types

[Timmy250]

Here is a pic as Bob suggested, not shimmed type of adjustment, I replaced the stock lash adjusters (floating ball and socket) because they were failing. Hard to see in pic, but one collet is damaged, it came free and rode up, where it was hammered by the rocker. The rest look well worn, I should have replaced before, I think.

It may come down to getting new valves that work with collets available.

This head is apparently an oddball, from an early 250, it has a small diameter intake port, 25 mm, and subject of an earlier discussion.

IMG_20140602_110751.jpg

[DewCatTea-Bob]

[quote= graeme ...
" How much clearance from the collet groove,
to the lower edge of the opening shim? "

____ The skirt-depth on the opening shim-caps varies by about 1mm, so Kev's DESMO-valve with the shallower tip-end may be less able to accommodate shim-caps with the deepest skirts.
However I believe the most acute combo with the greatest extremes matched-together, ends-up with the bottom-edge of the cap-skirt nearly flush with the top-edge of the groove-slot. _ Otherwise there's normally about 1mm of clearance between those two specified points.

____ I've compiled a combo-pic which attempts to directly-compare any notable difference between Kev's DESMO-valves & Tim's valve in question,, but the results aren't exactly fair due-to pic.shot angles, etc. _ And when I used angle-adjusting software to separately reset the oddly arranged angles of Kev's two displayed valve-stems (which were 7.5-degrees off-axis from each-other), that software unfortunately didn't also maintain the exact-same scale for them both,, so I then had to adjust their relative scale back towards equal, by-eye alone, (which I believe got re-matched back, within a 2% tolerance). _ And of-course I also had to do another similar scale match-up, in order to get the stem of the valve-in-question properly included within the same combo-pic (with the same scale-tolerance). _ Kind-of a fun challenge, in a way.
__ Although I had intended to display an obvious difference between the DESMO-valves & the valve in question, it seems that I've rather actually shown how very similar the stems of both valve-types really appear to be.
__ If ya pride your perception,, then without first reading the File-comment, ya might want-to try quizzing yourself on which valve-stem is of which valve-type, before-hand.


Dukaddy-DUKEs,
DCT-Bob

[DewCatTea-Bob]

[quote= Timmy250 ...
" Here is a pic as Bob suggested, "

____ Thanks for the pic (even though it's not much of a "close-up" on the odd valve-keepers).
____ Well anyway, those collet-halves sort-of appear to be the same uncommon type of v.keepers which I've encountered a couple of times in the distant-past !
But your posted-pic is-not concentrated closely enough on them for me to clearly tell whether they have a rib-ridge as I had expected,, or if instead, they ALSO have groove-slots like the valve-stems (which would then require C-clips inserted in-between).
I don't believe I've ever encountered such odd v.keepers which also made use of C-clips,, but as well as I can see within zoomed-in views of your posted-pic, it sure seems to appear as if your collet-halves have groove-slots instead of rib-ridges.
Can you please explain that (which your picture fails to make clearly obvious) ?



" one collet is damaged, it came free and rode up, "

____ I'm thinking that rather than working-free, it may've not been carefully fully fitted (groove-ridge into grove-slot), when last assembled.



" The rest look well worn, "

____ I've never seen brand-new examples of these type of valve-keepers, so I don't really know exactly what they're supposed to look like,, but all the used collect-halves I've seen, seemed to exhibit peculiar signs of questionable wear.


Hopeful-Cheers,
-Bob

[Eldert]

old Moto Guzzi split valve keepers will fit . and i think Ducati parr twin valve spring keepers to but i am not sure . never seen one apart .

Eldert

[Timmy250]

Bob, cell phone has a cheap camera. But the collets do have a rib ridge, that mates into the groove in the valve.

The older parts catalogue in the tech section of this site shows two different part numbers for the collets, ending at a motor number, and note that indicates the valves changed to match. Eurotrash Jambalaya stocks a collet with part number that matches the later, common collet, and confirms it is for the more common valve. Maybe that's a clue.

I will search for an old moto guzzi, maybe save need to replace valves. Thanks,

Tim

[DewCatTea-Bob]

[quote= Timmy250 ...
" the collets do have a rib ridge, that mates into the groove in the valve. "

____ Alright-then, then there's no doubt that they're the same type as those I've dealt-with before.



" The older parts catalogue
shows two different part numbers for the collets, ending at a motor number, and note that indicates the valves changed to match. "

____ It should also be checked to determine if the spring-ties were also changed to suit, as I think I recall that the newer-type collet-halves were somewhat thicker with a wider taper.


Hopeful-Cheers,
-Bob

[machten]

I've compiled a combo-pic which attempts to directly-compare any notable difference between Kev's DESMO-valves & the valve in question,, but the results aren't exactly fair due-to pic.shot angles, etc. _ And when I used angle-adjusting software to reset the oddly arranged angles of Kev's two valve-stems, that software didn't also maintain the exact-same scale for them both,, so I then had to adjust their relative scale back towards equal by-eye alone, (which I believe got re-matched within a 2% tolerance). _ And of-course I also had to do a similar scale match-up to get the valve-in-question properly included within the same combo-pic (with the same scale-tolerance). _ Kind-of a fun challenge, actually.

Nice job, DCT-Bob! Very impressive manipulation and useful for purposes of comparison.

I've never seen nor heard of such a collet arrangement...always nice to learn something new!

Kev

[Timmy250]

The MG collets are an exact match, thanks Eldert!

[DewCatTea-Bob]

[quote= Timmy250 ...
" The MG collets are an exact match, "

____ How have you become able to confirm that the MotoGuzzi v.keepers are exactly the very-same, have you somehow already personally acquired a couple new or used pairs ??
If so, then how about letting us know where you got them, and perhaps also post a close-up picture of them (taken from an angle which allows viewing of the top-edge of at-least one of the half-collets).
__ Have you measured the diameter at the top of the taper within the spring-tie (where the v.keeper/collet-halves fit into) ?


Hopeful-Cheers,
-Bob

[DewCatTea-Bob]

[quote= machten ...
" Very impressive manipulation and useful for purposes of comparison. "

____ The welcomed praise from you alone Kev, is sufficient reward for the time & effort spent on that endeavor ! _ And in fact has inspired me to go-onward further forth with it to the full degree which I had originally envisioned. - (See latest combo-pic version below.)


Cheers,
-Bob